Disabling keyboard keys

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In my textbox i want to enter only currency type numbers, i.e. if dot is entered and dot key is pressed again, it won't take and none of the alphabetical entry it will take...
can someone help me with this....

Posted 15-Jul-14 18:27pm

ShobuGpta

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johannesnestler 16-Jul-14 5:23am

also think about globalization - we german-speakers use the comma as decimal seperator....

Sergey Alexandrovich Kryukov 18-Jul-14 2:37am

It all depends on which TextBox. Full type name, please.
—SA

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ArunRajendra · Answer 1 · 2014-07-15T18:41:00

Solution 3

Alter native solutions using regex and masking.

http://stackoverflow.com/questions/7301447/restrict-characters-allowed-in-textboxentering-money-amount[^]
http://stackoverflow.com/questions/12209484/masking-textbox-to-accept-only-decimals[^]

Posted 15-Jul-14 18:41pm

ArunRajendra

Yellow_Flash · Answer 2 · 2014-07-15T18:34:00

Here is a code you have to put in the TextBox_KeyPress event
It will take only numbers

VB

Private Sub TextBoxes_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If Asc(e.KeyChar) <> 8 Then
      'Allow only numbers to enter
      If Not (Char.IsDigit(CChar(CStr(e.KeyChar))) Or e.KeyChar = ".") Then
        e.Handled = True
      End If
      'Allow only one decimal point
      If e.KeyChar = "."c AndAlso TryCast(sender, TextBox).Text.IndexOf("."c) > -1 Then
         e.Handled = True
      End If
    End If
  End Sub

This code is written in VB.net you can change in it C# easily

**HardikPatel.SE** · Answer 3 · 2014-07-15T18:41:00

This will help you... :)

Form validation using the keyboard events : Numbers only[^]

Or see this code :

HTML

<html>
  <head>
    <script language="Javascript">
       <!--
       function isNumberKey(evt)
       {
          var charCode = (evt.which) ? evt.which : event.keyCode
          if (charCode != 46 && charCode > 31 
            && (charCode < 48 || charCode > 57))
             return false;
 
          return true;
       }
       //-->
    </script>
  </head>
  <body>
    <input id="txtChar"  önkeypress="return isNumberKey(event)">
           type="text" name="txtChar">
  </input></body>
</html>

Reference : Text box should only accept only numbers and dot[^]

Pravuprasad · Answer 4 · 2014-07-15T18:49:00

Solution 4

C#

private void TextBoxes_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
	if (Strings.Asc(e.KeyChar) != 8)
         {
           //Allow numbers only
	   if (!(char.IsDigit(Convert.ToChar(Convert.ToString(e.KeyChar))) | e.KeyChar == ".")) 
            {
	      e.Handled = true;
	    }
	   //Allow decimal only
	 if (e.KeyChar == '.' && (sender as TextBox).Text.IndexOf('.') > -1) 
            {
	      e.Handled = true;
	    }
	  }
}

Posted 15-Jul-14 18:49pm

Pravuprasad

Comments

ShobuGpta 16-Jul-14 1:22am

this code is fine but it's also disabling backspace and, code for decimal is not working, when i press dot key its shows exception even for the first time(Object reference not set to an instance of an object).
and i dont understand this code "if (Strings.Asc(e.KeyChar) != 8)" why have u used this

ShobuGpta 16-Jul-14 1:53am

instead of "(sender as TextBox).Text.IndexOf('.') > -1" i used "textbox.text.contains(".")", it's working without any problem

johannesnestler 16-Jul-14 5:25am

try to run your "naive" code in another culture... Don't hardcode the "." use System.Globalization.CultureInfo.CurrentUICulture.NumberFormat.CurrencyDecimalSeparator instead

Ranjeet Patel · Answer 5 · 2014-07-15T23:21:00

If you want to use jQuery then this code can help you...

jquery

$(document).ready(function() {
    $("#txtboxToFilter").keydown(function (e) {
        // Allow: backspace, delete, tab, escape, enter and .
        if ($.inArray(e.keyCode, [46, 8, 9, 27, 13, 110, 190]) !== -1 ||
             // Allow: Ctrl+A
            (e.keyCode == 65 && e.ctrlKey === true) ||
             // Allow: home, end, left, right
            (e.keyCode >= 35 && e.keyCode <= 39)) {
                 // let it happen, don't do anything
                 return;
        }
        // Ensure that it is a number and stop the keypress
        if ((e.shiftKey || (e.keyCode < 48 || e.keyCode > 57)) && (e.keyCode < 96 || e.keyCode > 105)) {
            e.preventDefault();
        }
    });
});

Disabling keyboard keys

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