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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 > 10 Then
        MessageBox.Show("Please Enter a Number from 1 to 10")
        TxtBox.Focus()
    ElseIf TxtBox.Text < 10 Then
        MessageBox.Show("Thank You, your rating was " & TxtBox.Text)
        Total = Total + 1
    ElseIf IsNumeric(TxtBox.Text) Then
        MessageBox.Show("Thank you, your rating was " & ValueTxtBox.Text)
    End If

    ValueTxtBox.Clear()
    ValueTxtBox.Focus()
2018/12/10
1
28
12/10/2018 5:57:41 AM


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("[^\d]")
    TextBox.Text = digitsOnly.Replace(TextBox.Text, "")
End Sub

If you want to allow decimals, add

AndAlso Not e.KeyChar = "."

to the if statement in the KeyPress section.

2015/04/16

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
2014/11/13

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 > 0 AndAlso intValue < 11 Then
    MessageBox.Show("Thank You, your rating was " & TxtBox.Text)
Else
    MessageBox.Show("Please Enter a Number from 1 to 10")
End If
2018/12/10

Simplest ever solution for TextBox Validation in VB.NET

TextBox Validation for Visual Basic (VB.NET)

First, add new VB code file in your project.

  1. Go To Solution Explorer
  2. Right Click to your project
  3. Select Add > New item...
  4. Add new VB code file (i.e. example.vb)

or press Ctrl+Shift+A

COPY & 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("1234567890.", e.KeyChar) = 0 And Asc(e.KeyChar) <> 8 Or (e.KeyChar = "." And InStr(numbers.Text, ".") > 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("1234567890.()-+ ", e.KeyChar) = 0 And Asc(e.KeyChar) <> 8 Or (e.KeyChar = "." And InStr(numbers.Text, ".") > 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("[email protected]#$%^&*()_+=-", e.KeyChar) > 0 Then
            e.KeyChar = Chr(0)
            e.Handled = True
        End If
    End Sub
    Public Sub NotNull_Leave(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim No As Windows.Forms.TextBox = sender
        If No.Text.Trim = "" Then
            MsgBox("This field Must be filled!")
            No.Focus()
        End If
    End Sub
    Public Sub Email_Leave(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim Email As Windows.Forms.TextBox = sender
        If Email.Text <> "" Then
            Dim rex As Match = Regex.Match(Trim(Email.Text), "^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,3})$", RegexOptions.IgnoreCase)
            If rex.Success = False Then
                MessageBox.Show("Please Enter a valid Email Address", "Information", 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..!

2020/06/20

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.

2012/04/02

Source: https://stackoverflow.com/questions/9969824
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