How Do I Set A Textbox Only Accept Hexadecimal Values In C# Windows Form

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C#3.5

i ma struc in this above question please help me out this

Posted 8-Jan-16 22:30pm

Siddaram K.Patil

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4 solutions

Solution 3

One simple way is to use Control.Validating Event (System.Windows.Forms)[^]. In this event check that only characters allowed in hex values are present. If any extra characters are included, set e.Cancel to true.

Something like:

C#

private void textBox1_Validating(object sender, CancelEventArgs e)
      {
         char[] allowedChars = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

         foreach (char character in textBox1.Text.ToUpper().ToArray())
         {
            if (!allowedChars.Contains(character))
            {
               System.Windows.Forms.MessageBox.Show(string.Format("'{0}' is not a hexadecimal character", character));
               e.Cancel = true;
            }
         }
      }

Posted 8-Jan-16 22:51pm

Wendelius

Solution 5

Numeric input is best handled by a control designed specifically for that use. Sure a TextBox could be modified to accept a specific set of characters but to do it properly you would have to handle typed, pasted and possibly drag-dropped data.

Why bother when Microsoft provide the System.Windows.Forms.NumericUpDown control.

For example to make a NumericUpDown accept only hexadecimal values in the range 0x20 to 0xFF
1) Set Hexadecimal to true
2) Set Minimum to 0x20
3) Set Maximum to 0xFF

That's it.

Alan.

Posted 9-Jan-16 3:08am

Alan N

Solution 2

Have you tried this?

C#

void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    char c = e.KeyChar;
    
    if (c != '\b' && !((c <= 0x66 && c >= 61) || (c <= 0x46 && c >= 0x41) || (c >= 0x30 && c <= 0x39)))
    {
        e.Handled = true;
    }
}

Posted 8-Jan-16 22:44pm

Maciej Los

Updated 9-Jan-16 0:37am

v2

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OriginalGriff · Accepted Answer · 2016-01-08T22:43:00

Solution 1

There are several ways: but the easiest if to handle the KeyPressed event and limit the input to just 0-9, A-F, a-f:

C#

char c = e.KeyChar;
if (!((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f')))
   {
   e.Handled = true;
   }

Posted 8-Jan-16 22:43pm

OriginalGriff