How can I convert String to Int

Question

I have a TextBoxD1 Text and I want to convert it to an int to store it in a database    How can I do this

User · Answer

You can convert string to int many different type methods in C#

First one is mostly use :

string test = "123";
int x = Convert.ToInt16(test);

if int value is higher you should use int32 type.

Second one:

int x = int.Parse(text);

if you want to error check, you can use TryParse method. In below I add nullable type;

int i=0;
Int32.TryParse(text, out i) ? i : (int?)null);

Enjoy your codes....

User · Answer

Convert ToInt32  TextBoxD1 Text      Use this if you feel confident that the contents of the text box is a valid int  A safer option is  int val   0  Int32 TryParse  TextBoxD1 Text  out val      This will provide you with some default value you can use  Int32 TryParse also returns a Boolean value indicating whether it was able to parse or not  so you can even use it as the condition of an if statement   if  Int32 TryParse  TextBoxD1 Text  out val      DoSomething        else     HandleBadInput

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While I agree on using the TryParse method  a lot of people dislike the use of out parameter  myself included   With tuple support having been added to C   an alternative is to create an extension method that will limit the number of times you use out to a single instance  public static class StringExtensions       public static  int result  bool canParse  TryParse this string s                int res          var valid   int TryParse s  out res           return  result  res  canParse  valid             Source  C  how to convert a string to int

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You need to parse the string  and you also need to ensure that it is truly in the format of an integer   The easiest way is this   int parsedInt   0  if  int TryParse TextBoxD1 Text  out parsedInt           Code for if the string was valid   else         Code for if the string was invalid

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As explained in the TryParse documentation  TryParse   returns a Boolean which indicates that a valid number was found   bool success   Int32 TryParse TextBoxD1 Text  out val    if  success           Put val in database   else          Handle the case that the string doesn t contain a valid number

User · Answer

You can convert string to an integer value with the help of parse method    Eg    int val   Int32 parse stringToBeParsed   int x   Int32 parse 1234

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The way I always do this is like this   using System  using System Collections Generic  using System ComponentModel  using System Data  using System Drawing  using System Linq  using System Text  using System Windows Forms   namespace example string to int       public partial class Form1   Form               public Form1                         InitializeComponent                       private void button1 Click object sender  EventArgs e                        string a   textBox1 Text                 This turns the text in text box 1 into a string             int b              if   int TryParse a  out b                                 MessageBox Show  This is not a number                              else                               textBox2 Text   a   is a number                                 Then this  if  statement says if the string is not a number  display an error  else now you will have an integer                      This is how I would do it

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Enjoy it     int i   0  string s    123   i  int Parse s   i   Convert ToInt32 s

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You can try the following  It will work   int x   Convert ToInt32 TextBoxD1 Text     The string value in the variable TextBoxD1 Text will be converted into Int32 and will be stored in x

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In C  v 7 you could use an inline out parameter  without an additional variable declaration   int TryParse TextBoxD1 Text  out int x

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int x   0  int TryParse TextBoxD1 Text  out x     The TryParse statement returns a boolean representing whether the parse has succeeded or not  If it succeeded  the parsed value is stored into the second parameter   See Int32 TryParse Method  String  Int32  for more detailed information

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Try this   int x   Int32 Parse TextBoxD1 Text     or better yet   int x   0   Int32 TryParse TextBoxD1 Text  out x     Also  since Int32 TryParse returns a bool you can use its return value to make decisions about the results of the parsing attempt   int x   0   if  Int32 TryParse TextBoxD1 Text  out x            you know that the parsing attempt        was successful     If you are curious  the difference between Parse and TryParse is best summed up like this      The TryParse method is like the Parse   method  except the TryParse method   does not throw an exception if the   conversion fails  It eliminates the   need to use exception handling to test   for a FormatException in the event   that s is invalid and cannot be   successfully parsed  - MSDN

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METHOD 1  int  TheAnswer1   0  bool Success   Int32 TryParse  42   out TheAnswer1   if   Success        Console WriteLine  String not Convertable to an Integer        METHOD 2  int TheAnswer2   0  try       TheAnswer2   Int32 Parse  42      catch       Console WriteLine  String not Convertable to an Integer        METHOD 3  int TheAnswer3   0  try       TheAnswer3   Int32 Parse  42      catch  FormatException        Console WriteLine  String not in the correct format for an Integer      catch  ArgumentNullException        Console WriteLine  String is null      catch  OverflowException        Console WriteLine  String represents a number less than                           MinValue or greater than MaxValue

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This would do  string x   TextBoxD1 Text  int xi   Convert ToInt32 x     Or you can use  int xi   Int32 Parse x     Refer Microsoft Developer Network for more information

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You can write your own extension method  public static class IntegerExtensions       public static int ParseInt this string value  int defaultValue   0                int parsedValue          if  int TryParse value  out parsedValue                         return parsedValue                     return defaultValue             public static int  ParseNullableInt this string value                if  string IsNullOrEmpty value                         return null                     return value ParseInt              And wherever in code just call  int myNumber   someString ParseInt       Returns value or 0 int age   someString ParseInt 18      With default value 18 int  userId   someString ParseNullableInt       Returns value or null   In this concrete case  int yourValue   TextBoxD1 Text ParseInt

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Conversion of string to int can be done for  int  Int32  Int64 and other data types reflecting integer data types in  NET  Below example shows this conversion   This show  for info  data adapter element initialized to int value  The same can be done directly like   int xxiiqVal   Int32 Parse strNabcd     Ex   string strNii       UsrDataAdapter SelectCommand Parameters   Nii   Value   Int32 Parse strNii      Link to see this demo

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int myInt   int Parse TextBoxD1 Text    Another way would be   bool isConvertible   false  int myInt   0   isConvertible   int TryParse TextBoxD1 Text  out myInt     The difference between the two is that the first one would throw an exception if the value in your textbox can t be converted  whereas the second one would just return false

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You can use either   int i   Convert ToInt32 TextBoxD1 Text     or  int i   int Parse TextBoxD1 Text

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This may help you  D        public partial class Form1   Form               public Form1                         InitializeComponent                       float Stukprijs          float Aantal          private void label2 Click object sender  EventArgs e                                private void button2 Click object sender  EventArgs e                        MessageBox Show  In de eersre textbox staat een geldbedrag     Environment NewLine    In de tweede textbox staat een aantal     Environment NewLine    Bereken wat er moetworden betaald     Environment NewLine    Je krijgt 15  korting over het bedrag BOVEN de 100     Environment NewLine    Als de korting meer dan 10 euri is     Environment NewLine    wordt de korting textbox lichtgroen                       private void button1 Click object sender  EventArgs e                        errorProvider1 Clear                errorProvider2 Clear                if  float TryParse textBox1 Text  out Stukprijs                                 if  float TryParse textBox2 Text  out Aantal                                         float Totaal   Stukprijs   Aantal                      string Output   Totaal ToString                        textBox3 Text   Output                      if  Totaal  gt   100                                                float korting   Totaal - 100                          float korting2   korting   100   15                          string Output2   korting2 ToString                            textBox4 Text   Output2                          if  korting2  gt   10                                                        textBox4 BackColor   Color LightGreen                                                    else                                                       textBox4 BackColor   SystemColors Control                                                                      else                                               textBox4 Text    0                           textBox4 BackColor   SystemColors Control                                                          else                                       errorProvider2 SetError textBox2   Aantal plz                                                  else                               errorProvider1 SetError textBox1   Bedrag plz                     if  float TryParse textBox2 Text  out Aantal                                                        else                                       errorProvider2 SetError textBox2   Aantal plz                                                         private void BTNwissel Click object sender  EventArgs e                          LL  LU  LR  LD              Color c   LL BackColor              LL BackColor   LU BackColor              LU BackColor   LR BackColor              LR BackColor   LD BackColor              LD BackColor   c                     private void button3 Click object sender  EventArgs e                        MessageBox Show  zorg dat de kleuren linksom wisselen als je op de knop drukt

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int TryParse     It won t throw if the text is not numeric

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May be quite some time ago but I just want throw in some line for any one who may still need it  int intValue  string strValue    2021    try       intValue   Convert ToInt32 strValue     catch         Default Value if conversion fails OR return specified error        Example      intValue   2000

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You also may use an extension method  so it will be more readable  although everybody is already used to the regular Parse functions    public static class StringExtensions            lt summary gt          Converts a string to int           lt  summary gt           lt param name  value  gt The string to convert  lt  param gt           lt returns gt The converted integer  lt  returns gt      public static int ParseToInt32 this string value                return int Parse value                   lt summary gt          Checks whether the value is integer           lt  summary gt           lt param name  value  gt The string to check  lt  param gt           lt param name  result  gt The out int parameter  lt  param gt           lt returns gt true if the value is an integer  otherwise  false  lt  returns gt      public static bool TryParseToInt32 this string value  out int result                return int TryParse value  out result             And then you can call it that way    If you are sure that your string is an integer  like  50    int num   TextBoxD1 Text ParseToInt32     If you are not sure and want to prevent crashes   int num  if  TextBoxD1 Text TryParseToInt32 out num           The parse was successful  the num has the parsed value       To make it more dynamic  so you can parse it also to double  float  etc   you can make a generic extension

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This code works for me in Visual Studio 2010   int someValue   Convert ToInt32 TextBoxD1 Text

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int i   Convert ToInt32 TextBoxD1 Text

User · Answer

You can do like below without TryParse or inbuilt functions   static int convertToInt string a        int x   0      for  int i   0  i  lt  a Length  i                  int temp   a i  -  0           if  temp    0                        x    temp    int Math Pow 10   a Length -  i 1                         return x

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Be careful when using Convert ToInt32   on a char  It will return the UTF-16 code of the character   If you access the string only in a certain position using the  i  indexing operator  it will return a char and not a string   String input    123678                                               int indexOfSeven    4   int x   Convert ToInt32 input indexOfSeven                   Returns 55  int x   Convert ToInt32 input indexOfSeven  toString         Returns 7

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This works for me   using System   namespace numberConvert       class Program               static void Main string   args                        string numberAsString    8               int numberAsInt   int Parse numberAsString

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While there are already many solutions here that describe int Parse  there s something important missing in all the answers  Typically  the string representations of numeric values differ by culture  Elements of numeric strings such as currency symbols  group  or thousands  separators  and decimal separators all vary by culture    If you want to create a robust way to parse a string to an integer  it s therefore important to take the culture information into account  If you don t  the current culture settings will be used  That might give a user a pretty nasty surprise -- or even worse  if you re parsing file formats  If you just want English parsing  it s best to simply make it explicit  by specifying the culture settings to use   var culture   CultureInfo GetCulture  en-US    int result   0  if  int TryParse myString  NumberStyles Integer  culture  out result            use result        For more information  read up on CultureInfo  specifically NumberFormatInfo on MSDN

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If you re looking for the long way  just create your one method   static int convertToInt string a                int x   0           Char   charArray   a ToCharArray            int j   charArray Length           for  int i   0  i  lt  charArray Length  i                          j--              int s    int Math Pow 10  j                x      int Char GetNumericValue charArray i     s                     return x

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int x   Int32 TryParse TextBoxD1 Text  out x    x   0

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You can convert a string to int in C  using   Functions of convert class i e  Convert ToInt16    Convert ToInt32    Convert ToInt64   or by using Parse and TryParse Functions  Examples are given here

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All above answers are good but for information  we can use int TryParse which is safe to convert string to int   example    TryParse returns true if the conversion succeeded    and stores the result in j  int j  if  Int32 TryParse  quot -105 quot   out j      Console WriteLine j   else    Console WriteLine  quot String could not be parsed  quot       Output  -105  TryParse never throws an exception   even on invalid input and null  It is overall preferable to int Parse in most program contexts  Source  How to convert string to int in C    With Difference between Int Parse and Int TryParse

[c#] How can I convert String to Int?

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