VB net Need Text Box to Only Accept Numbers

Question

I m fairly new to VB net  self taught  and was just wondering if someone out there could help me out with some code  I m not trying to do anything too involved  just have a TextBox that accepts a numeric value from 1 to 10  I don t want it to accept a string or any number above 10  If someone types a word or character an error message will appear  telling him to enter a valid number  This is what I have  obviously it s not great as I am having problems  Thanks again to anyone who can help     If TxtBox Text  gt  10 Then         MessageBox Show  Please Enter a Number from 1 to 10           TxtBox Focus       ElseIf TxtBox Text  lt  10 Then         MessageBox Show  Thank You  your rating was    amp  TxtBox Text          Total   Total   1     ElseIf IsNumeric TxtBox Text  Then         MessageBox Show  Thank you  your rating was    amp  ValueTxtBox Text      End If      ValueTxtBox Clear       ValueTxtBox Focus

User · Answer

every text box has a validating and validated event you can use then as follows  -  Private Sub PriceTxt Validating ByVal sender As Object  ByVal e As System ComponentModel CancelEventArgs  Handles PriceTxt Validating                 If Not IsNumeric PriceTxt Text  Then                  PriceTxt BackColor   Color Red                  MsgBox  The Price Should Be Numeric Only   Enter Again   vbCritical                   PriceTxt Text                       PriceTxt BackColor   Color White                 End If End Sub

User · Answer

This was my final    It gets around all the type issues also   Here is a simple textbox that requires a number      public Sub textbox memorytotal TextChanged sender As Object  e As EventArgs  Handles textbox memorytotal TextChanged         TextboxOnlyNumbers sender      End Sub   and here is the procedure that corrects all bad input   Public Sub TextboxOnlyNumbers ByRef objTxtBox As TextBox         ONLY allow numbers     If Not IsNumeric objTxtBox Text  Then            Don t process things like too many backspaces         If objTxtBox Text Length  gt  0 Then              MsgBox  Numerical Values only                 Try                   If something bad was entered delete the last character                 objTxtBox Text   objTxtBox Text Substring 0  objTxtBox Text Length - 1                     Put the cursor and the END of the corrected number                 objTxtBox Select objTxtBox Text Length   1  1               Catch ex As Exception             End Try         End If     End If End Sub

User · Answer

Public Function Isnumber ByVal KCode As String  As Boolean     If Not Isnumeric KCode  And KCode  lt  gt  ChrW Keys Back  And KCode  lt  gt  ChrW Keys Enter  And KCode  lt  gt     c Then          MsgBox  Please Enter Numbers only   MsgBoxStyle OkOnly      End If End Function  Private Sub txtBalance KeyPress ByVal sender As System Object  ByVal e As  System Windows Forms KeyPressEventArgs  Handles txtBalance KeyPress      If Not Isnumber e KeyChar  Then         e KeyChar          End If  End Sub

User · Answer

This may be too late  but for other new blood on VB out there  here s something simple   First  in any case  unless your application would require  blocking user s key entry is somehow not a good thing to do  users may misinterpret the action as problem on the hardware keyboard and at the same time may not see where their keypreesed entry error came from    Here s a simple one  let user s freely type their entry then trap the error later     Private Sub Button1 Click ByVal sender As System Object  ByVal e As System EventArgs  Handles Button1 Click         Dim theNumber As Integer         Dim theEntry As String   Trim TextBox1 Text            This check if entry can be converted to          numeric value from 0-10  if cannot return a negative value          Try             theNumber   Convert ToInt32 theEntry              If theNumber  lt  0 Or theNumber  gt  10 Then theNumber   -1         Catch ex As Exception             theNumber   -1         End Try           Trap for the valid and invalid numeric number         If theNumber  lt  0 Or theNumber  gt  10 Then             MsgBox  Invalid Entry  allows  0-10  only                 entry was invalid return cursor to entry box              TextBox1 Focus           Else              Entry accepted                Continue process your thing here             End If     End Sub

User · Answer

Private Sub MyTextBox KeyPress sender As Object  e As System Windows Forms KeyPressEventArgs  Handles MyTextBox KeyPress     If Not IsNumeric e KeyChar  And Not e KeyChar   ChrW Keys Back  Then         e Handled   True     End If End Sub

User · Answer

Copy this function in any module inside your vb net project   Public Function MakeTextBoxNumeric kcode As Integer  shift As Boolean  As Boolean     If kcode  gt   96 And kcode  lt   105 Then      ElseIf kcode  gt   48 And kcode  lt   57         If shift   True Then Return False     ElseIf kcode   8 Or kcode   107 Then      ElseIf kcode   187 Then         If shift   False Then Return False     Else         Return False     End If     Return True End Function   Then use this function inside your textbox keydown event like below   Private Sub txtboxNumeric KeyDown sender As Object  e As KeyEventArgs  Handles txtboxNumeric KeyDown If MakeTextBoxNumeric e KeyCode  e Shift    False Then e SuppressKeyPress   True End Sub   And yes  It works 100

User · Answer

Very simple piece of code that works for me   Private Sub Textbox1 KeyPress sender As Object  e As KeyPressEventArgs  Handles textbox1 KeyPress         If Asc e KeyChar   gt  58 Then             e KeyChar    quot  quot           End If     End Sub

User · Answer

If Not Char IsNumber e KeyChar  AndAlso Not e KeyChar       AndAlso Not Char IsControl e KeyChar  Then             e KeyChar      End If   This allow you to use delete key and set decimal points

User · Answer

Simplest ever solution for TextBox Validation in VB NET  First  add new VB code file in your project   Go To Solution Explorer Right Click to your project Select Add  gt  New item    Add new VB code file  i e  example vb   or press Ctrl Shift A COPY  amp  PASTE following code into this file and give it a suitable name   i e  KeyValidation vb  Imports System Text RegularExpressions Module Module1     Public Enum ValidationType         Only Numbers   1         Only Characters   2         Not Null   3         Only Email   4         Phone Number   5     End Enum     Public Sub AssignValidation ByRef CTRL As Windows Forms TextBox  ByVal Validation Type As ValidationType          Dim txt As Windows Forms TextBox   CTRL         Select Case Validation Type             Case ValidationType Only Numbers                 AddHandler txt KeyPress  AddressOf number Leave             Case ValidationType Only Characters                 AddHandler txt KeyPress  AddressOf OCHAR Leave             Case ValidationType Not Null                 AddHandler txt Leave  AddressOf NotNull Leave             Case ValidationType Only Email                 AddHandler txt Leave  AddressOf Email Leave             Case ValidationType Phone Number                 AddHandler txt KeyPress  AddressOf Phonenumber Leave         End Select     End Sub     Public Sub number Leave ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs          Dim numbers As Windows Forms TextBox   sender         If InStr  quot 1234567890  quot   e KeyChar    0 And Asc e KeyChar   lt  gt  8 Or  e KeyChar    quot   quot  And InStr numbers Text   quot   quot    gt  0  Then             e KeyChar   Chr 0              e Handled   True         End If     End Sub     Public Sub Phonenumber Leave ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs          Dim numbers As Windows Forms TextBox   sender         If InStr  quot 1234567890   -   quot   e KeyChar    0 And Asc e KeyChar   lt  gt  8 Or  e KeyChar    quot   quot  And InStr numbers Text   quot   quot    gt  0  Then             e KeyChar   Chr 0              e Handled   True         End If     End Sub     Public Sub OCHAR Leave ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs          If InStr  quot 1234567890       amp       - quot   e KeyChar   gt  0 Then             e KeyChar   Chr 0              e Handled   True         End If     End Sub     Public Sub NotNull Leave ByVal sender As Object  ByVal e As System EventArgs          Dim No As Windows Forms TextBox   sender         If No Text Trim    quot  quot  Then             MsgBox  quot This field Must be filled  quot               No Focus           End If     End Sub     Public Sub Email Leave ByVal sender As Object  ByVal e As System EventArgs          Dim Email As Windows Forms TextBox   sender         If Email Text  lt  gt   quot  quot  Then             Dim rex As Match   Regex Match Trim Email Text    quot    0-9a-zA-Z   -  w   0-9a-zA-Z      0-9a-zA-Z  - w   0-9a-zA-Z      a-zA-Z  2 3    quot   RegexOptions IgnoreCase              If rex Success   False Then                 MessageBox Show  quot Please Enter a valid Email Address quot    quot Information quot   MessageBoxButtons OK  MessageBoxIcon Information                  Email BackColor   Color Red                 Email Focus                   Exit Sub             Else                 Email BackColor   Color White             End If         End If     End Sub End Module  Now use following code to Form Load Event like below  Private Sub Form1 Load ByVal sender As System Object  ByVal e As System EventArgs  Handles MyBase Load         AssignValidation Me TextBox1  ValidationType Only Digits          AssignValidation Me TextBox2  ValidationType Only Characters          AssignValidation Me TextBox3  ValidationType No Blank          AssignValidation Me TextBox4  ValidationType Only Email  End Sub  Done

User · Answer

Private Sub Data KeyPress sender As Object  e As KeyPressEventArgs  Handles Data KeyPress     If  Not e KeyChar   ChrW Keys Back  And   0123456789    IndexOf e KeyChar    -1  Or  e KeyChar       And Data Text ToCharArray   Count Function c  c         gt  0  Then         e Handled   True     End If End Sub

User · Answer

I know this post is old but I wanted to share something I have implemented to turn a TextBox into what I call an IntBox   First you need to make an extension with    lt Runtime CompilerServices Extension   gt    Public Function HandledStringtoInteger s As String  As Integer     Try         If s   String Empty Then             Return 0         Else             Return Integer Parse s          End If     Catch         Dim result As String   String Empty         Dim ReturnInt As Integer         Dim Parsed As Integer         For Each Character In s ToCharArray             If Character    -  Then                 If s Substring 0  1  ToString  lt  gt   -  Then                     result   Character   result                 End If             End If             If Character       Then                 Exit For             End If             If Integer TryParse Character  Parsed  Then                 result   result   Parsed ToString             End If         Next         If result  lt  gt  String Empty Then             If Integer TryParse result  ReturnInt  Then                 Return Integer Parse ReturnInt              Else                 If Double Parse result   gt  Double Parse Integer MaxValue ToString  Then                     Return Integer MaxValue                 ElseIf Double Parse result   lt  Double Parse Integer MinValue ToString  Then                     Return Integer MinValue                 Else                     Return Integer Parse ReturnInt                  End If             End If         Else             Return 0         End If     End Try End Function   Then make a TextChanged event sub   Private Sub TextBox to IntBox sender As Object  e As TextChangedEventArgs  Handles YourTextBox TextChanged     If DirectCast sender  TextBox  IsKeyboardFocused Then         DirectCast sender  TextBox  Text   DirectCast sender  TextBox  Text HandledStringtoInteger         DirectCast sender  TextBox  CaretIndex   DirectCast sender  TextBox  Text Length     End If End Sub   Then whenever the user enters text it evaluates the string and only returns numeric values that are within the bounds of a standard Integer  With the  -  character you can change the integer from positive to negative and back again   If anyone sees anything that can improve this code let me know but my tests show this works fantastic to make an IntBox   EDIT  I found another method that can work if you use properties in your code   Note this will need a separate property per TextBox   First create the property   Public Class Properties     Implement INotifyPropertyChanged      Private  Variable as Integer     Public Property YourProperty as Object     get       Return  Variable     end get     set value as Object         Variable   value ToString ToInteger  I will give the ToInteger extension code later     end set     end property Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged PropertyChanged  Public Sub OnPropertyChange ByVal e As PropertyChangedEventArgs      If Not PropertyChangedEvent Is Nothing Then         RaiseEvent PropertyChanged Me  e      End If End Sub End Class   Then make the binding in your window s main class   Public WithEvents  YourVariable as New Properties  Public Sub New       InitializeComponent   With YourTextBox    SetBinding Textbox TextProperty  New Binding  YourProperty       DataContext    YourVariable End With End Sub   Finally here is the ToInteger Extension Code I set up        lt summary gt      Handles conversion of variable to Integer       lt  summary gt       lt param name  X  gt  lt  param gt       lt param name  I  gt Returned if conversion fails  lt  param gt       lt returns gt Signed 32bit Integer lt  returns gt       lt remarks gt  lt  remarks gt   lt Runtime CompilerServices Extension   gt    Public Function toInteger Of T  ByRef X As T  Optional I As Integer   0  As Integer     Dim S As String   X ToString     Try         If S   String Empty Then             Return I         Else             Return Integer Parse S          End If     Catch         Dim result As String   String Empty         Dim ReturnInt As Integer         Dim Parsed As Byte         For Each Character In S ToCharArray             If Character    -  Then                 If S Substring 0  1  ToString  lt  gt   -  Then                     result   Character   result                 End If             End If             If Character       Then                 Exit For             End If             If Byte TryParse Character  Parsed  Then                 result   result   Parsed ToString             End If         Next         If result  lt  gt  String Empty Then             If Integer TryParse result  ReturnInt  Then                 Return Integer Parse ReturnInt              Else                 If Double Parse result   gt  Double Parse Integer MaxValue ToString  Then                     Return Integer MaxValue                 ElseIf Double Parse result   lt  Double Parse Integer MinValue ToString  Then                     Return Integer MinValue                 Else                     Return Integer Parse ReturnInt                  End If             End If         Else             Return I         End If     End Try End Function   With all these combined whenever they type something into the box it will act as if it were a textbox but when they change focus the ToInteger extension will set the value as an integer into the property and return it to the textbox   Meaning that if the operator entered  -1w3  after focus changes it will return as  -13  automatically

User · Answer

You can use the onkeydown Property of the TextBox for limiting its value to numbers only    lt asp TextBox ID  TextBox1  runat  server  onkeydown    return    event keyCode gt  65   amp  amp  event keyCode  32    gt  lt  asp TextBox gt      keyCode  65  check is for excludng Alphabets   keyCode  32 check is for excluding Space character inbetween the numbers   If you want to exclude Symbols also from entering into the textbox  then include the below condition also in the  onkeydown  property     event shiftKey  amp  amp   event keyCode  gt   48  amp  amp  event keyCode  lt   57     Thus the TextBox will finally become    lt asp TextBox ID  TextBox1  runat  server  onkeydown    return    event keyCode gt  65   amp  amp  event keyCode  32  amp  amp    event shiftKey  amp  amp   event keyCode  gt   48  amp  amp  event keyCode  lt   57      gt  lt  asp TextBox gt    Explanation   KeyCode for  a  is  65  and  z  is  90    KeyCodes from  90  to  222  which are other symbols are also not needed   KeyCode for  Space  Key is  32  which is also not needed   Then a combination of  Shift  key and  Number  keys  which denotes Symbols  also not needed  KeyCode for  0  is  48  and  9  is  57    Hence all these are included in the TextBox declaration itself which produces the desired result   Try and see

User · Answer

Private Sub textBox5 KeyPress sender As System Object  e As System Windows Forms KeyPressEventArgs  Handles textBox5 KeyPress         If Asc e KeyChar   lt  gt  8 Then             If Asc e KeyChar   lt  48 Or Asc e KeyChar   gt  57 Then                 e Handled   True             End If         End If     End Sub

User · Answer

First of all set the TextBox s MaxLength to 2 that will limit the amount of text entry in your TextBox  Then you can try something like this using the KeyPress Event  Since you are using a 2 digit maximum  10  you will need to use a Key such as Enter to initiate the check    Private Sub TextBox1 KeyPress sender As System Object  e As System Windows Forms KeyPressEventArgs  Handles TextBox1 KeyPress     Dim tb As TextBox   CType sender  TextBox      If Not IsNumeric e KeyChar  Then     Check if Numeric         If Char IsControl e KeyChar  Then   If not Numeric Check if a Control             If e KeyChar   ChrW Keys Enter  Then                 If Val tb Text   gt  10 Then   Check Bounds                     tb Text                          ShowPassFail False                  Else                     ShowPassFail True                  End If                 e Handled   True             End If             Exit Sub         End If         e Handled   True         ShowPassFail False      End If End Sub  Private Sub ShowPassFail pass As Boolean      If pass Then         MessageBox Show  Thank you  your rating was    amp  TextBox1 Text      Else         MessageBox Show  Please Enter a Number from 1 to 10       End If     TextBox1 Clear       TextBox1 Focus   End Sub

User · Answer

This is what I did in order to handle both key entry and copy paste  Private Sub TextBox KeyPress ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs  Handles TextBox KeyPress     If Not Char IsNumber e KeyChar  AndAlso Not Char IsControl e KeyChar  Then         e Handled   True     End If End Sub  Private Sub TextBox TextChanged ByVal sender As Object  ByVal e As System EventArgs  Handles TextBox TextChanged     Dim digitsOnly As Regex   New Regex  quot    d  quot       TextBox Text   digitsOnly Replace TextBox Text   quot  quot   End Sub  If you want to allow decimals and negative amount  add AndAlso Not e KeyChar    quot   quot  AndAlso Not e keyChar    quot - quot   to the if statement in the KeyPress section

User · Answer

On each entry in textbox  event - Handles RestrictedTextBox TextChanged   you can do a try to caste entered text into integer  if failure occurs  you just reset the value of the text in RestrictedTextBox to last valid entry  which gets constantly updating under the temp1 variable    Here s how to go about it  In the sub that loads with the form  me load or mybase load   initialize temp1 to the default value of RestrictedTextBox Text  Dim temp1 As Integer  initialize temp1 default value  you should do this after the default value for RestrictedTextBox Text was loaded  If  RestrictedTextBox Text   Nothing  Then      temp1   Nothing Else     Try          temp1   CInt RestrictedTextBox Text      Catch ex As Exception         temp1   Nothing     End Try End If      At any other point in form   Private Sub textBox TextChanged sender As System Object  e As System EventArgs  Handles RestrictedTextBox TextChanged     Try         temp1   CInt RestrictedTextBox Text   If user inputs integer  this will succeed and temp will be updated     Catch ex As Exception         RestrictedTextBox Text   temp1 ToString  If user inputs non integer  textbox will be reverted to state the state it was in before the string entry     End Try End Sub   The nice thing about this is that you can use this to restrict a textbox to any type you want  double  uint etc

User · Answer

I know this post is old but I want to share my code    Private Sub txtbox1 TextChanged sender As Object  e As EventArgs  Handles txtbox1 TextChanged     If txtbox1 Text Length  gt  0 Then         If Not IsNumeric txtbox1 Text  Then             Dim sel As Integer   txtbox1 SelectionStart             txtbox1 Text   txtbox1 Text Remove sel - 1  1              txtbox1 SelectionStart   sel - 1         End If     End If End Sub

User · Answer

You must first validate if the input is actually an integer  You can do it with Integer TryParse   Dim intValue As Integer If Integer TryParse TxtBox Text  intValue  AndAlso intValue  gt  0 AndAlso intValue  lt  11 Then     MessageBox Show  Thank You  your rating was    amp  TxtBox Text  Else     MessageBox Show  Please Enter a Number from 1 to 10   End If

User · Answer

Try this   Private Sub txtCaseID KeyPress ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs  Handles txtCaseID KeyPress     If Not Char IsNumber e KeyChar  AndAlso Not Char IsControl e KeyChar  Then e KeyChar      End Sub

User · Answer

You Can use Follow code Textbox Keypress Event  Private Sub txtbox1 KeyPress ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs  Handles txtbox1 KeyPress     Try         If Val txtbox1 text   lt  10 Then             If Char IsLetterOrDigit e KeyChar    False And Char IsControl e KeyChar    False Then                 e Handled   True             End If         Else             e Handled   True         End If     Catch ex As Exception         ShowException ex Message  MESSAGEBOX TITLE  ex      End Try End Sub  This code allow numbers only and you can enter only number between 1 to 10

User · Answer

You could avoid any code by using a NumericUpDown control rather than a text box  this automatically only allows numbers and has a max and min  It also allow accessing the number directly with NumericUpDown1 Value as well as using up and down arrows to set the number  Also if a number higher over the max is entered it will jump to the nearest allowed number

User · Answer

This worked for me    just clear the textbox completely as non-numeric keys are pressed   Private Sub TextBox2 TextChanged sender As Object  e As EventArgs  Handles TextBox2 TextChanged     If IsNumeric TextBox2 Text  Then          nada     Else         TextBox2 Clear       End If End Sub

User · Answer

Use this in your Textbox Keydown event   Private Sub TextBox1 KeyDown ByVal sender As Object  ByVal e As System Windows Forms KeyEventArgs  Handles TextBox1 KeyDown      you can enter decimal  if nonNumberEntered e  TextBox1  True  then        otherwise just numbers  if nonNumberEntered e  TextBox1  then      If nonNumberEntered e  TextBox1  True  Then         e SuppressKeyPress   True     End If     If e KeyCode   Keys Enter Then          put your code here     End If  End Sub   Copy this function in any module inside your vb net project    Public Function nonNumberEntered ByVal e As System Windows Forms KeyEventArgs                              ByVal ob As TextBox                              Optional ByVal decim As Boolean   False  As Boolean     nonNumberEntered   False      If decim Then           Determine whether the keystroke is a number from the top of the keyboard          If e KeyCode  lt  Keys D0 OrElse e KeyCode  gt  Keys D9 Then               Determine whether the keystroke is a number from the keypad              If e KeyCode  lt  Keys NumPad0 OrElse e KeyCode  gt  Keys NumPad9 Then                 If e KeyCode  lt  gt  Keys Decimal And e KeyCode  lt  gt  Keys OemPeriod Then                     If e KeyCode  lt  gt  Keys Divide And e KeyCode  lt  gt  Keys OemQuestion Then                           Determine whether the keystroke is a backspace                          If e KeyCode  lt  gt  Keys Back And e KeyCode  lt  gt  Keys Delete                           And e KeyCode  lt  gt  Keys Left And e KeyCode  lt  gt  Keys Right Then                               A non-numerical keystroke was pressed                               nonNumberEntered   True                         End If                     ElseIf ob Text Contains      Or ob Text Length   0 Then                         nonNumberEntered   True                     End If                 ElseIf ob Text Contains      Or ob Text Length   0 Then                     nonNumberEntered   True                 End If             End If         End If     Else           Determine whether the keystroke is a number from the top of the keyboard          If e KeyCode  lt  Keys D0 OrElse e KeyCode  gt  Keys D9 Then               Determine whether the keystroke is a number from the keypad              If e KeyCode  lt  Keys NumPad0 OrElse e KeyCode  gt  Keys NumPad9 Then                   Determine whether the keystroke is a backspace                  If e KeyCode  lt  gt  Keys Back And e KeyCode  lt  gt  Keys Delete                       And e KeyCode  lt  gt  Keys Left And e KeyCode  lt  gt  Keys Right Then                       A non-numerical keystroke was pressed                       nonNumberEntered   True                 End If             End If         End If     End If       If shift key was pressed  it s not a number      If Control ModifierKeys   Keys Shift Then         nonNumberEntered   True     End If  End Function   This will allow numbers like 2 4 or numbers like 3 5 to be entered in your textbox if using decim  nonNumberEntered e Textbox1  True     Allows only numbers to be entered in textbox if using  nonNumberEntered e Textbox1  False   or  nonNumberEntered e Textbox1        Edit  added text

User · Answer

Dim ch 10  As Char Dim len As Integer len   TextBox1 Text Length ch   TextBox1 Text ToCharArray   For i   0 To len - 1     If Not IsNumeric ch i   Then         MsgBox  Value you insert is not numeric       End If Next

User · Answer

You can do this with the use of Ascii integers  Put this code in the Textbox s Keypress event  e KeyChar represents the key that s pressed  And the the built-in function Asc   converts it into its Ascii integer   Private Sub TextBox1 KeyPress ByVal sender As Object  ByVal e As System Windows Forms KeyPressEventArgs  Handles TextBox1 KeyPress       97 - 122   Ascii codes for simple letters      65 - 90    Ascii codes for capital letters      48 - 57    Ascii codes for numbers      If Asc e KeyChar   lt  gt  8 Then         If Asc e KeyChar   lt  48 Or Asc e KeyChar   gt  57 Then             e Handled   True         End If     End If  End Sub

User · Answer

I know it s old   I ll just leave this code here for the sake of convenience  Integer only  Public Sub TextBox1 TextChanged sender As Object  e As EventArgs  Handles TextBox1 TextChanged    With TextBox1       If IsNumeric  Text  Then  Text    Text Select Function x  If IsNumeric x   x   quot  quot       SelectionStart    TextLength    End With      etc   End Sub  Accepts Double  Public Sub TextBox1 TextChanged sender As Object  e As EventArgs  Handles TextBox1 TextChanged    With TextBox1       If IsNumeric  Text  Then  Text    Text Select Function x  If IsNumeric x  Or x    quot   quot   x   quot  quot       SelectionStart    TextLength    End With      etc   End Sub  Accepts basic operations   -      parentheses             and Double  Public Sub TextBox1 TextChanged sender As Object  e As EventArgs  Handles TextBox1 TextChanged    With TextBox1       If IsNumeric  Text  Then  Text    Text Select Function x  If IsNumeric x  Or  quot   -         quot  Contains x   x   quot  quot       SelectionStart    TextLength    End With      etc   End Sub

User · Answer

I had a similar use requirement recently for a TextBox which could only take numbers    In the end I used a MaskedTextBox instead of a TextBox  You define a  mask  for the textbox and it will only accept characters which you have defined - in this case  numbers  The downside is that it leaves a bit of an ugly line within the TextBox     What I loved about the MaskedTextBox was it was so customisable  If  for whatever reason you wanted a TextBox to only accept an input in the format of 3 ints followed by 2 letters  all you need to do is set the TextMask to 000LL  There are a load of pre-defined masks within Visual Studio  and the full documentation can be found here     Now  I know this doesn t fully solve your issue  but the use of a MaskedTextBox takes away a huge part of the complexity of the problem  You can now guarantee that the contents of the MaskedTextBox will only ever be an Int  allowing you to run a simple If statement to ensure the value is   lt 10

[vb.net] VB.net Need Text Box to Only Accept Numbers

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