how to make textbox who only allow integer value?

i want to make a textbox in my wpf application开发者_StackOverflow中文版 which will accept only integer values. if someone types characters between [a-z], the textbox will reject it. Thus it will not be displayed in the textbox

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You can handle the PreviewTextInput event:

private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
  // Filter out non-digit text input
  foreach (char c in e.Text) 
    if (!Char.IsDigit(c)) 
    {
      e.Handled = true;
      break;
    }
}

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In WPF, you can handle the KeyDown event like this:

private void MyTextBox_KeyDown(object sender, KeyDownEventArgs e)
{
    e.Handled = true;
}

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You can add handle of the TextChanged event and look what was entered (need to check all text every time for preventing pasting letters from clipboard).

Also look a very good example of creating maskable editbox on CodeProject.

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this simple code snippet should do the trick.. You might also want to check for overflows (too large numbers)

private void IntegerTextBox_TextChanged(object sender, EventArgs e)
{
    for (int i = 0; i < Text.Length; i++)
    {
        int c = Text[i];
        if (c < '0' || c > '9')
        {
           Text = Text.Remove(i, 1);
         }
    }
}

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Bind it to Integer property. WPF will do the validation itself without any extra hassle.