How to format a string as a telephone number in C

Question

I have a string  1112224444  it is a telephone number  I want to format as 111-222-4444 before I store it in a file  It is on a datarecord and I would prefer to be able to do this without assigning a new variable   I was thinking   String Format   0    -   -        i  MyPhone   ToString        but that does not seem to do the trick      UPDATE     Ok  I went with this solution  Convert ToInt64 i  Customer Phone    ToString     -   -              Now its gets messed up when the extension is less than 4 digits  It will fill in the numbers from the right  so  1112224444 333  becomes  11-221-244 3334   Any ideas

User · Answer

As far as I know you can t do this with string Format     you would have to handle this yourself   You could just strip out all non-numeric characters and then do something like   string Format    0    1 - 2         phoneNumber Substring 0  3        phoneNumber Substring 3  3        phoneNumber Substring 6      This assumes the data has been entered correctly  which you could use regular expressions to validate

User · Answer

string phoneNum          string phoneFormat    0 -   -   -               phoneNum   Convert ToInt64  011234567891   ToString phoneFormat

User · Answer

The following will work with out use of regular expression  string primaryContactNumber    string IsNullOrEmpty formData Profile Phone    String Format   0    -   -        long Parse formData Profile Phone           If we dont use long Parse    the string format will not work

User · Answer

You ll need to break it into substrings  While you could do that without any extra variables  it wouldn t be particularly nice  Here s one potential solution   string phone   i  MyPhone   ToString    string area   phone Substring 0  3   string major   phone Substring 3  3   string minor   phone Substring 6   string formatted   string Format   0 - 1 - 2    area  major  minor

User · Answer

static string FormatPhoneNumber  string phoneNumber         if   String IsNullOrEmpty phoneNumber          return phoneNumber      Regex phoneParser   null     string format               switch  phoneNumber Length            case 5            phoneParser   new Regex     d 3    d 2               format          1  2          break         case 6            phoneParser   new Regex     d 2    d 2    d 2               format          1  2  3          break         case 7            phoneParser   new Regex     d 3    d 2    d 2               format          1  2  3          break         case 8            phoneParser   new Regex     d 4    d 2    d 2               format          1  2  3          break         case 9            phoneParser   new Regex     d 4    d 3    d 2    d 2               format          1  2  3  4          break         case 10            phoneParser   new Regex     d 3    d 3    d 2    d 2               format          1  2  3  4          break         case 11            phoneParser   new Regex     d 4    d 3    d 2    d 2               format          1  2  3  4          break         default          return phoneNumber         switch     return phoneParser Replace  phoneNumber  format        FormatPhoneNumber      enter code here

User · Answer

Not to resurrect an old question but figured I might offer at least a slightly easier to use method  if a little more complicated of a setup   So if we create a new custom formatter we can use the simpler formatting of string Format without having to convert our phone number to a long  So first lets create the custom formatter   using System  using System Globalization  using System Text   namespace System            lt summary gt              A formatter that will apply a format to a string of numeric values           lt  summary gt           lt example gt              The following example converts a string of numbers and inserts dashes between them               lt code gt          public class Example                        public static void Main                                             string stringValue    123456789                              Console WriteLine String Format new NumericStringFormatter                                                       0   formatted   0    -  -        stringValue                                           The example displays the following output                   123456789  formatted  123-45-6789            lt  code gt           lt  example gt      public class NumericStringFormatter   IFormatProvider  ICustomFormatter                    lt summary gt                  Converts the value of a specified object to an equivalent string representation using specified format and                 culture-specific formatting information               lt  summary gt               lt param name  format  gt A format string containing formatting specifications  lt  param gt               lt param name  arg  gt An object to format  lt  param gt               lt param name  formatProvider  gt An object that supplies format information about the current instance  lt  param gt               lt returns gt                  The string representation of the value of  lt paramref name  arg    gt   formatted as specified by                  lt paramref name  format    gt  and  lt paramref name  formatProvider    gt                lt  returns gt               lt exception cref  System NotImplementedException  gt  lt  exception gt          public string Format string format  object arg  IFormatProvider formatProvider                        var strArg   arg as string                   If the arg is not a string then determine if it can be handled by another formatter             if  strArg    null                                try                                       return HandleOtherFormats format  arg                                     catch  FormatException e                                        throw new FormatException string Format  The format of   0   is invalid    format   e                                                   If the format is not set then determine if it can be handled by another formatter             if  string IsNullOrEmpty format                                 try                                       return HandleOtherFormats format  arg                                     catch  FormatException e                                        throw new FormatException string Format  The format of   0   is invalid    format   e                                               var sb   new StringBuilder                var i   0               foreach  var c in format                                if  c                                               if  i  lt  strArg Length                                                sb Append strArg i                                              i                                      else                                       sb Append c                                                return sb ToString                            lt summary gt                  Returns an object that provides formatting services for the specified type               lt  summary gt               lt param name  formatType  gt An object that specifies the type of format object to return  lt  param gt               lt returns gt                  An instance of the object specified by  lt paramref name  formatType    gt   if the                  lt see cref  T System IFormatProvider    gt  implementation can supply that type of object  otherwise  null               lt  returns gt          public object GetFormat Type formatType                           Determine whether custom formatting object is requested               return formatType    typeof ICustomFormatter    this   null                     private string HandleOtherFormats string format  object arg                        if  arg is IFormattable                  return   IFormattable arg  ToString format  CultureInfo CurrentCulture               else if  arg    null                  return arg ToString                else                 return string Empty                      So then if you want to use this you would do something this   String Format new NumericStringFormatter     0    -   -        i  MyPhone   ToString       Some other things to think about   Right now if you specified a longer formatter than you did a string to format it will just ignore the additional   signs  For example this String Format new NumericStringFormatter     0    -   -         12345    would result in 123-45- so you might want to have it take some kind of possible filler character in the constructor   Also I didn t provide a way to escape a   sign so if you wanted to include that in your output string you wouldn t be able to the way it is right now   The reason I prefer this method over Regex is I often have requirements to allow users to specify the format themselves and it is considerably easier for me to explain how to use this format than trying to teach a user regex   Also the class name is a bit of misnomer since it actually works to format any string as long as you want to keep it in the same order and just inject characters inside of it

User · Answer

I prefer to use regular expressions   Regex Replace  1112224444       d 3    d 3    d 4       1- 2- 3

User · Answer

You may get find yourself in the situation where you have users trying to enter phone numbers with all sorts of separators between area code and the main number block  e g   spaces  dashes  periods  ect     So you ll want to strip the input of all characters that are not numbers so you can sterilize the input you are working with  The easiest way to do this is with a RegEx expression   string formattedPhoneNumber   new System Text RegularExpressions Regex    D        Replace originalPhoneNumber  string Empty     Then the answer you have listed should work in most cases   To answer what you have about your extension issue  you can strip anything that is longer than the expected length of ten  for a regular phone number  and add that to the end using  formattedPhoneNumber   Convert ToInt64 formattedPhoneNumber        ToString     -   -         new String       value Length - 10       You will want to do an  if  check to determine if the length of your input is greater than 10 before doing this  if not  just use   formattedPhoneNumber   Convert ToInt64 value  ToString     -   -

User · Answer

You ll need to break it into substrings  While you could do that without any extra variables  it wouldn t be particularly nice  Here s one potential solution   string phone   i  MyPhone   ToString    string area   phone Substring 0  3   string major   phone Substring 3  3   string minor   phone Substring 6   string formatted   string Format   0 - 1 - 2    area  major  minor

User · Answer

You can try  0   000  000-      if your target number starts with 0

User · Answer

Please note  this answer works with numeric data types  int  long   If you are starting with a string  you ll need to convert it to a number first  Also  please take into account that you ll need to validate that the initial string is at least 10 characters in length   From a good page full of examples   String Format   0          -        8005551212        This will output   800  555-1212     Although a regex may work even better  keep in mind the old programming quote      Some people  when confronted with a   problem  think    I know  I   ll use   regular expressions     Now they have   two problems               --Jamie Zawinski  in comp lang emacs

User · Answer

public string phoneformat string phnumber    String phone phnumber  string countrycode   phone Substring 0  3    string Areacode   phone Substring 3  3    string number   phone Substring 6 phone Length     phnumber     countrycode      Areacode  -   number    return phnumber      Output will be  001-568-895623

User · Answer

If you can get i  MyPhone   as a long  you can use the long ToString   method to format it   Convert ToLong i  MyPhone    ToString     -   -          See the MSDN page on Numeric Format Strings   Be careful to use long rather than int  int could overflow

User · Answer

You may get find yourself in the situation where you have users trying to enter phone numbers with all sorts of separators between area code and the main number block  e g   spaces  dashes  periods  ect     So you ll want to strip the input of all characters that are not numbers so you can sterilize the input you are working with  The easiest way to do this is with a RegEx expression   string formattedPhoneNumber   new System Text RegularExpressions Regex    D        Replace originalPhoneNumber  string Empty     Then the answer you have listed should work in most cases   To answer what you have about your extension issue  you can strip anything that is longer than the expected length of ten  for a regular phone number  and add that to the end using  formattedPhoneNumber   Convert ToInt64 formattedPhoneNumber        ToString     -   -         new String       value Length - 10       You will want to do an  if  check to determine if the length of your input is greater than 10 before doing this  if not  just use   formattedPhoneNumber   Convert ToInt64 value  ToString     -   -

User · Answer

You can also try this     public string GetFormattedPhoneNumber string phone                        if  phone    null  amp  amp  phone Trim   Length    10                  return string Format    0    1 - 2    phone Substring 0  3   phone Substring 3  3   phone Substring 6  4                    return phone              Output

User · Answer

Please note  this answer works with numeric data types  int  long   If you are starting with a string  you ll need to convert it to a number first  Also  please take into account that you ll need to validate that the initial string is at least 10 characters in length   From a good page full of examples   String Format   0          -        8005551212        This will output   800  555-1212     Although a regex may work even better  keep in mind the old programming quote      Some people  when confronted with a   problem  think    I know  I   ll use   regular expressions     Now they have   two problems               --Jamie Zawinski  in comp lang emacs

User · Answer

You can also try this     public string GetFormattedPhoneNumber string phone                        if  phone    null  amp  amp  phone Trim   Length    10                  return string Format    0    1 - 2    phone Substring 0  3   phone Substring 3  3   phone Substring 6  4                    return phone              Output

User · Answer

Function FormatPhoneNumber ByVal myNumber As String      Dim mynewNumber As String     mynewNumber          myNumber   myNumber Replace          Replace          Replace  -           If myNumber Length  lt  10 Then         mynewNumber   myNumber     ElseIf myNumber Length   10 Then         mynewNumber        amp  myNumber Substring 0  3   amp        amp                  myNumber Substring 3  3   amp   -   amp  myNumber Substring 6  3      ElseIf myNumber Length  gt  10 Then         mynewNumber        amp  myNumber Substring 0  3   amp        amp                  myNumber Substring 3  3   amp   -   amp  myNumber Substring 6  3   amp       amp                  myNumber Substring 10      End If     Return mynewNumber End Function

User · Answer

I suggest this as a clean solution for US numbers   public static string PhoneNumber string value         if  string IsNullOrEmpty value   return string Empty      value   new System Text RegularExpressions Regex    D            Replace value  string Empty       value   value TrimStart  1        if  value Length    7          return Convert ToInt64 value  ToString     -            if  value Length    10          return Convert ToInt64 value  ToString     -   -            if  value Length  gt  10          return Convert ToInt64 value               ToString     -   -         new String       value Length - 10         return value

User · Answer

using string interpolation and the new array index range var p    quot 1234567890 quot   var formatted     quot   p 0  3     p 3  6  - p 6  10   quot   Output   123  456-7890

User · Answer

To take care of your extension issue  how about   string formatString       -   -            returnValue   Convert ToInt64 phoneNumber                        ToString formatString Substring 0 phoneNumber Length 3                         Trim

User · Answer

Use Match in Regex to split  then output formatted string with match groups  Regex regex   new Regex      lt first3chr gt  d 3     lt next3chr gt  d 3     lt next4chr gt  d 4      Match match   regex Match phone   if  match Success  return       match Groups  first3chr   ToString                    match Groups  next3chr   ToString      -    match Groups  next4chr   ToString

User · Answer

static string FormatPhoneNumber  string phoneNumber         if   String IsNullOrEmpty phoneNumber          return phoneNumber      Regex phoneParser   null     string format               switch  phoneNumber Length            case 5            phoneParser   new Regex     d 3    d 2               format          1  2          break         case 6            phoneParser   new Regex     d 2    d 2    d 2               format          1  2  3          break         case 7            phoneParser   new Regex     d 3    d 2    d 2               format          1  2  3          break         case 8            phoneParser   new Regex     d 4    d 2    d 2               format          1  2  3          break         case 9            phoneParser   new Regex     d 4    d 3    d 2    d 2               format          1  2  3  4          break         case 10            phoneParser   new Regex     d 3    d 3    d 2    d 2               format          1  2  3  4          break         case 11            phoneParser   new Regex     d 4    d 3    d 2    d 2               format          1  2  3  4          break         default          return phoneNumber         switch     return phoneParser Replace  phoneNumber  format        FormatPhoneNumber      enter code here

User · Answer

As far as I know you can t do this with string Format     you would have to handle this yourself   You could just strip out all non-numeric characters and then do something like   string Format    0    1 - 2         phoneNumber Substring 0  3        phoneNumber Substring 3  3        phoneNumber Substring 6      This assumes the data has been entered correctly  which you could use regular expressions to validate

User · Answer

Use Match in Regex to split  then output formatted string with match groups  Regex regex   new Regex      lt first3chr gt  d 3     lt next3chr gt  d 3     lt next4chr gt  d 4      Match match   regex Match phone   if  match Success  return       match Groups  first3chr   ToString                    match Groups  next3chr   ToString      -    match Groups  next4chr   ToString

User · Answer

If you can get i  MyPhone   as a long  you can use the long ToString   method to format it   Convert ToLong i  MyPhone    ToString     -   -          See the MSDN page on Numeric Format Strings   Be careful to use long rather than int  int could overflow

User · Answer

using string interpolation and the new array index range var p    quot 1234567890 quot   var formatted     quot   p 0  3     p 3  6  - p 6  10   quot   Output   123  456-7890

User · Answer

Function FormatPhoneNumber ByVal myNumber As String      Dim mynewNumber As String     mynewNumber          myNumber   myNumber Replace          Replace          Replace  -           If myNumber Length  lt  10 Then         mynewNumber   myNumber     ElseIf myNumber Length   10 Then         mynewNumber        amp  myNumber Substring 0  3   amp        amp                  myNumber Substring 3  3   amp   -   amp  myNumber Substring 6  3      ElseIf myNumber Length  gt  10 Then         mynewNumber        amp  myNumber Substring 0  3   amp        amp                  myNumber Substring 3  3   amp   -   amp  myNumber Substring 6  3   amp       amp                  myNumber Substring 10      End If     Return mynewNumber End Function

User · Answer

Use Match in Regex to split  then output formatted string with match groups  Regex regex   new Regex      lt first3chr gt  d 3     lt next3chr gt  d 3     lt next4chr gt  d 4      Match match   regex Match phone   if  match Success  return       match Groups  first3chr   ToString                    match Groups  next3chr   ToString      -    match Groups  next4chr   ToString

User · Answer

Label12 Text   Convert ToInt64 reader 6   ToString  quot          -      quot     This is my example  I hope can help you with this  regards

User · Answer

Please use the following link for C  http   www beansoftware com NET-Tutorials format-string-phone-number aspx  The easiest way to do format is using Regex   private string FormatPhoneNumber string phoneNum      string phoneFormat             -     x          Regex regexObj   new Regex      d       phoneNum   regexObj Replace phoneNum         if  phoneNum Length  gt  0          phoneNum   Convert ToInt64 phoneNum  ToString phoneFormat         return phoneNum      Pass your phoneNum as string 2021231234 up to 15 char   FormatPhoneNumber string phoneNum    Another approach would be to use Substring  private string PhoneFormat string phoneNum              int max   15  min   10        string areaCode   phoneNum Substring 0  3         string mid   phoneNum Substring 3  3         string lastFour   phoneNum Substring 6  4         string extension   phoneNum Substring 10  phoneNum Length - min         if  phoneNum Length    min                  return     areaCode    mid - lastFour                  else if  phoneNum Length  gt  min  amp  amp  phoneNum Length  lt   max                  return     areaCode    mid - lastFour  x extension                  return phoneNum

User · Answer

I prefer to use regular expressions   Regex Replace  1112224444       d 3    d 3    d 4       1- 2- 3

User · Answer

I prefer to use regular expressions   Regex Replace  1112224444       d 3    d 3    d 4       1- 2- 3

User · Answer

Here is another way of doing it    public string formatPhoneNumber string  phoneNum        string phoneNum    phoneNum      if  phoneNum    null          phoneNum           phoneNum   phoneNum PadRight 10 - phoneNum Length       phoneNum   phoneNum Insert 0       Insert 4       Insert 9  -        return phoneNum

User · Answer

If your looking for a  US  phone number to be converted in real time  I suggest using this extension  This method works perfectly without filling in the numbers backwards  The String Format solution appears to work backwards  Just apply this extension to your string   public static string PhoneNumberFormatter this string value        value   new Regex    D   Replace value  string Empty       value   value TrimStart  1         if  value Length    0          value   string Empty      else if  value Length  lt  3          value   string Format    0     value Substring 0  value Length        else if  value Length  lt  7          value   string Format    0    1    value Substring 0  3   value Substring 3  value Length - 3        else if  value Length  lt  11          value   string Format    0    1 - 2    value Substring 0  3   value Substring 3  3   value Substring 6        else if  value Length  gt  10                value   value Remove value Length - 1  1           value   string Format    0    1 - 2    value Substring 0  3   value Substring 3  3   value Substring 6              return value

User · Answer

string phoneNum          string phoneFormat    0 -   -   -               phoneNum   Convert ToInt64  011234567891   ToString phoneFormat

User · Answer

You can try  0   000  000-      if your target number starts with 0

User · Answer

Label12 Text   Convert ToInt64 reader 6   ToString  quot          -      quot     This is my example  I hope can help you with this  regards

User · Answer

This should work   String Format   0         -        Convert ToInt64  1112224444       OR in your case   String Format   0    -   -        Convert ToInt64  1112224444

User · Answer

Not to resurrect an old question but figured I might offer at least a slightly easier to use method  if a little more complicated of a setup   So if we create a new custom formatter we can use the simpler formatting of string Format without having to convert our phone number to a long  So first lets create the custom formatter   using System  using System Globalization  using System Text   namespace System            lt summary gt              A formatter that will apply a format to a string of numeric values           lt  summary gt           lt example gt              The following example converts a string of numbers and inserts dashes between them               lt code gt          public class Example                        public static void Main                                             string stringValue    123456789                              Console WriteLine String Format new NumericStringFormatter                                                       0   formatted   0    -  -        stringValue                                           The example displays the following output                   123456789  formatted  123-45-6789            lt  code gt           lt  example gt      public class NumericStringFormatter   IFormatProvider  ICustomFormatter                    lt summary gt                  Converts the value of a specified object to an equivalent string representation using specified format and                 culture-specific formatting information               lt  summary gt               lt param name  format  gt A format string containing formatting specifications  lt  param gt               lt param name  arg  gt An object to format  lt  param gt               lt param name  formatProvider  gt An object that supplies format information about the current instance  lt  param gt               lt returns gt                  The string representation of the value of  lt paramref name  arg    gt   formatted as specified by                  lt paramref name  format    gt  and  lt paramref name  formatProvider    gt                lt  returns gt               lt exception cref  System NotImplementedException  gt  lt  exception gt          public string Format string format  object arg  IFormatProvider formatProvider                        var strArg   arg as string                   If the arg is not a string then determine if it can be handled by another formatter             if  strArg    null                                try                                       return HandleOtherFormats format  arg                                     catch  FormatException e                                        throw new FormatException string Format  The format of   0   is invalid    format   e                                                   If the format is not set then determine if it can be handled by another formatter             if  string IsNullOrEmpty format                                 try                                       return HandleOtherFormats format  arg                                     catch  FormatException e                                        throw new FormatException string Format  The format of   0   is invalid    format   e                                               var sb   new StringBuilder                var i   0               foreach  var c in format                                if  c                                               if  i  lt  strArg Length                                                sb Append strArg i                                              i                                      else                                       sb Append c                                                return sb ToString                            lt summary gt                  Returns an object that provides formatting services for the specified type               lt  summary gt               lt param name  formatType  gt An object that specifies the type of format object to return  lt  param gt               lt returns gt                  An instance of the object specified by  lt paramref name  formatType    gt   if the                  lt see cref  T System IFormatProvider    gt  implementation can supply that type of object  otherwise  null               lt  returns gt          public object GetFormat Type formatType                           Determine whether custom formatting object is requested               return formatType    typeof ICustomFormatter    this   null                     private string HandleOtherFormats string format  object arg                        if  arg is IFormattable                  return   IFormattable arg  ToString format  CultureInfo CurrentCulture               else if  arg    null                  return arg ToString                else                 return string Empty                      So then if you want to use this you would do something this   String Format new NumericStringFormatter     0    -   -        i  MyPhone   ToString       Some other things to think about   Right now if you specified a longer formatter than you did a string to format it will just ignore the additional   signs  For example this String Format new NumericStringFormatter     0    -   -         12345    would result in 123-45- so you might want to have it take some kind of possible filler character in the constructor   Also I didn t provide a way to escape a   sign so if you wanted to include that in your output string you wouldn t be able to the way it is right now   The reason I prefer this method over Regex is I often have requirements to allow users to specify the format themselves and it is considerably easier for me to explain how to use this format than trying to teach a user regex   Also the class name is a bit of misnomer since it actually works to format any string as long as you want to keep it in the same order and just inject characters inside of it

User · Answer

To take care of your extension issue  how about   string formatString       -   -            returnValue   Convert ToInt64 phoneNumber                        ToString formatString Substring 0 phoneNumber Length 3                         Trim

User · Answer

This should work   String Format   0         -        Convert ToInt64  1112224444       OR in your case   String Format   0    -   -        Convert ToInt64  1112224444

User · Answer

As far as I know you can t do this with string Format     you would have to handle this yourself   You could just strip out all non-numeric characters and then do something like   string Format    0    1 - 2         phoneNumber Substring 0  3        phoneNumber Substring 3  3        phoneNumber Substring 6      This assumes the data has been entered correctly  which you could use regular expressions to validate

User · Answer

If your looking for a  US  phone number to be converted in real time  I suggest using this extension  This method works perfectly without filling in the numbers backwards  The String Format solution appears to work backwards  Just apply this extension to your string   public static string PhoneNumberFormatter this string value        value   new Regex    D   Replace value  string Empty       value   value TrimStart  1         if  value Length    0          value   string Empty      else if  value Length  lt  3          value   string Format    0     value Substring 0  value Length        else if  value Length  lt  7          value   string Format    0    1    value Substring 0  3   value Substring 3  value Length - 3        else if  value Length  lt  11          value   string Format    0    1 - 2    value Substring 0  3   value Substring 3  3   value Substring 6        else if  value Length  gt  10                value   value Remove value Length - 1  1           value   string Format    0    1 - 2    value Substring 0  3   value Substring 3  3   value Substring 6              return value

User · Answer

If you can get i  MyPhone   as a long  you can use the long ToString   method to format it   Convert ToLong i  MyPhone    ToString     -   -          See the MSDN page on Numeric Format Strings   Be careful to use long rather than int  int could overflow

User · Answer

Please note  this answer works with numeric data types  int  long   If you are starting with a string  you ll need to convert it to a number first  Also  please take into account that you ll need to validate that the initial string is at least 10 characters in length   From a good page full of examples   String Format   0          -        8005551212        This will output   800  555-1212     Although a regex may work even better  keep in mind the old programming quote      Some people  when confronted with a   problem  think    I know  I   ll use   regular expressions     Now they have   two problems               --Jamie Zawinski  in comp lang emacs

User · Answer

You ll need to break it into substrings  While you could do that without any extra variables  it wouldn t be particularly nice  Here s one potential solution   string phone   i  MyPhone   ToString    string area   phone Substring 0  3   string major   phone Substring 3  3   string minor   phone Substring 6   string formatted   string Format   0 - 1 - 2    area  major  minor

User · Answer

Please use the following link for C  http   www beansoftware com NET-Tutorials format-string-phone-number aspx  The easiest way to do format is using Regex   private string FormatPhoneNumber string phoneNum      string phoneFormat             -     x          Regex regexObj   new Regex      d       phoneNum   regexObj Replace phoneNum         if  phoneNum Length  gt  0          phoneNum   Convert ToInt64 phoneNum  ToString phoneFormat         return phoneNum      Pass your phoneNum as string 2021231234 up to 15 char   FormatPhoneNumber string phoneNum    Another approach would be to use Substring  private string PhoneFormat string phoneNum              int max   15  min   10        string areaCode   phoneNum Substring 0  3         string mid   phoneNum Substring 3  3         string lastFour   phoneNum Substring 6  4         string extension   phoneNum Substring 10  phoneNum Length - min         if  phoneNum Length    min                  return     areaCode    mid - lastFour                  else if  phoneNum Length  gt  min  amp  amp  phoneNum Length  lt   max                  return     areaCode    mid - lastFour  x extension                  return phoneNum

User · Answer

You ll need to break it into substrings  While you could do that without any extra variables  it wouldn t be particularly nice  Here s one potential solution   string phone   i  MyPhone   ToString    string area   phone Substring 0  3   string major   phone Substring 3  3   string minor   phone Substring 6   string formatted   string Format   0 - 1 - 2    area  major  minor

User · Answer

The following will work with out use of regular expression  string primaryContactNumber    string IsNullOrEmpty formData Profile Phone    String Format   0    -   -        long Parse formData Profile Phone           If we dont use long Parse    the string format will not work

User · Answer

I prefer to use regular expressions   Regex Replace  1112224444       d 3    d 3    d 4       1- 2- 3

User · Answer

If you can get i  MyPhone   as a long  you can use the long ToString   method to format it   Convert ToLong i  MyPhone    ToString     -   -          See the MSDN page on Numeric Format Strings   Be careful to use long rather than int  int could overflow

User · Answer

As far as I know you can t do this with string Format     you would have to handle this yourself   You could just strip out all non-numeric characters and then do something like   string Format    0    1 - 2         phoneNumber Substring 0  3        phoneNumber Substring 3  3        phoneNumber Substring 6      This assumes the data has been entered correctly  which you could use regular expressions to validate

User · Answer

Try this  string result  if     string IsNullOrEmpty phoneNumber    amp  amp   phoneNumber Length  gt   10         result   string Format   0         -  new string     phoneNumber Length-6           Convert ToInt64 phoneNumber         else     result   phoneNumber  return result    Cheers

User · Answer

Please note  this answer works with numeric data types  int  long   If you are starting with a string  you ll need to convert it to a number first  Also  please take into account that you ll need to validate that the initial string is at least 10 characters in length   From a good page full of examples   String Format   0          -        8005551212        This will output   800  555-1212     Although a regex may work even better  keep in mind the old programming quote      Some people  when confronted with a   problem  think    I know  I   ll use   regular expressions     Now they have   two problems               --Jamie Zawinski  in comp lang emacs

User · Answer

Use Match in Regex to split  then output formatted string with match groups  Regex regex   new Regex      lt first3chr gt  d 3     lt next3chr gt  d 3     lt next4chr gt  d 4      Match match   regex Match phone   if  match Success  return       match Groups  first3chr   ToString                    match Groups  next3chr   ToString      -    match Groups  next4chr   ToString

User · Answer

Try this  string result  if     string IsNullOrEmpty phoneNumber    amp  amp   phoneNumber Length  gt   10         result   string Format   0         -  new string     phoneNumber Length-6           Convert ToInt64 phoneNumber         else     result   phoneNumber  return result    Cheers

User · Answer

Here is another way of doing it    public string formatPhoneNumber string  phoneNum        string phoneNum    phoneNum      if  phoneNum    null          phoneNum           phoneNum   phoneNum PadRight 10 - phoneNum Length       phoneNum   phoneNum Insert 0       Insert 4       Insert 9  -        return phoneNum

User · Answer

public string phoneformat string phnumber    String phone phnumber  string countrycode   phone Substring 0  3    string Areacode   phone Substring 3  3    string number   phone Substring 6 phone Length     phnumber     countrycode      Areacode  -   number    return phnumber      Output will be  001-568-895623

User · Answer

I suggest this as a clean solution for US numbers   public static string PhoneNumber string value         if  string IsNullOrEmpty value   return string Empty      value   new System Text RegularExpressions Regex    D            Replace value  string Empty       value   value TrimStart  1        if  value Length    7          return Convert ToInt64 value  ToString     -            if  value Length    10          return Convert ToInt64 value  ToString     -   -            if  value Length  gt  10          return Convert ToInt64 value               ToString     -   -         new String       value Length - 10         return value

[c#] How to format a string as a telephone number in C#

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