Member Avatar for geetajlo

Hi i want to prevent the user from entering number and special charaters in a textbox and another textbox from entering alphabets and specials characters .....

Need it quickly coz 2moro have to submit my project...

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  • 3 Replies
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  • 8 Months Discussion Span
  • Latest Post Latest Post by sabeerpasha

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Generated

Nice starting points from , , and . One caution: KeyPress filtering only catches keystrokes. Users can still paste, drag-drop, or your code can set the Text property directly. Also, the thread is tagged asp.net:vb.net, while those handlers are WinForms. Here are safer, minimal patterns for both cases.

ASP.NET Web Forms (validate on the page and again on the server):

<asp:TextBox ID="txtNumbers" runat="server" />
<asp:RegularExpressionValidator runat="server"
    ControlToValidate="txtNumbers"
    ValidationExpression="^[0-9]+$"
    ErrorMessage="Numbers only." />

<asp:TextBox ID="txtLetters" runat="server" />
<asp:RegularExpressionValidator runat="server"
    ControlToValidate="txtLetters"
    ValidationExpression="^[A-Za-z ]+$"
    ErrorMessage="Letters and spaces only." />
' Always re-check server-side
If Not System.Text.RegularExpressions.Regex.IsMatch(txtNumbers.Text, "^[0-9]+$") Then
    ' reject or show message
End If

WinForms (validate the full value, not individual keys):

Imports System.ComponentModel
Imports System.Text.RegularExpressions

Private ReadOnly reDigits As New Regex("^[0-9]+$")
Private ReadOnly reLetters As New Regex("^[A-Za-z ]+$")

Private Sub TextBoxNumbers_Validating(sender As Object, e As CancelEventArgs) _
    Handles TextBoxNumbers.Validating
    e.Cancel = Not reDigits.IsMatch(TextBoxNumbers.Text)
End Sub

Private Sub TextBoxLetters_Validating(sender As Object, e As CancelEventArgs) _
    Handles TextBoxLetters.Validating
    e.Cancel = Not reLetters.IsMatch(TextBoxLetters.Text)
End Sub

Tips:

  • Use [0-9] if you want ASCII digits only; \d can match other Unicode digits.
  • If you must block paste in WinForms, set ShortcutsEnabled = False, but still keep the Validating check.
  • For fixed formats, a MaskedTextBox can be simpler than custom code.

Recommended Answers

All 3 Replies

Member Avatar for Jx_Man

This following code just allowed you to entered numbers only (No alphabetics or any special characters) :

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If (Microsoft.VisualBasic.Asc(e.KeyChar) < 48) _
              Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 57) Then
            e.Handled = True
    End If
    If (Microsoft.VisualBasic.Asc(e.KeyChar) = 8) Then
            e.Handled = False
    End If
End Sub

This following code just allowed you to entered strings / alphabetics only (no numbers or any special characters):

Private Sub TextBox2_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox2.KeyPress
        If (Microsoft.VisualBasic.Asc(e.KeyChar) < 65) _
            Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 90) _
            And (Microsoft.VisualBasic.Asc(e.KeyChar) < 97) _
            Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 122) Then
            'Allowed space
            If (Microsoft.VisualBasic.Asc(e.KeyChar) <> 32) Then
                e.Handled = True
            End If
        End If
        ' Allowed backspace
        If (Microsoft.VisualBasic.Asc(e.KeyChar) = 8) Then
            e.Handled = False
        End If
End Sub
commented: lets talk about powerfull code of you. great man +1
Member Avatar for Pgmer

To make text box to accept only numbers, in key press event of that textbox u can code like this


If Char.IsDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
e.Handled = True
MsgBox("Please enter valid number ")
End If


i think u can mannage other one..

Member Avatar for sabeerpasha

Hi i want to prevent the user from entering number and special charaters in a textbox and another textbox from entering alphabets and specials characters .....

Need it quickly coz 2moro have to submit my project...

--------
Use the following code..
#Region "TextBox Events"

Private Sub txtFinRefNo_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtFinRefNo.KeyPress
Try
If Char.IsLetterOrDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
e.Handled = True
End If
Catch ex As Exception
ShowException(ex.Message, MESSAGEBOX_TITLE, ex)
End Try
End Sub
#End Region

sabeer pasha.

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