KeyDown event - how to easily know if the key pressed is numeric?

Question

I am currently handling the KeyDown event of a DataGridView control. One of the columns is filled by calculated values and I want the user to be able to override the cell va

Answer 1

Sorcerer86pt's solution was the simplest, however, when a user presses a control key, like backspace, then it breaks. To solve that problem, you can use the following snippet:

void KeyPress(object sender, KeyPressEventArgs e)
{    
    if(!Char.IsNumber(e.KeyChar) && !Char.IsControl(e.KeyChar))
    {
        //The char is not a number or a control key
        //Handle the event so the key press is accepted
        e.Handled = true;
        //Get out of there - make it safe to add stuff after the if statement
        return;
    }
    //e.Handled remains false so the keypress is not accepted
}

If you're using WPF, you might find that a TextBox doesn't have a KeyPressed event. To fix this, I used the following code.

void ValidateKeyPress(object sender, KeyEventArgs e)
{
    char keyPressed = WPFUtils.Interop.Keyboard.GetCharFromKey(e.Key);
    if (!Char.IsNumber(keyPressed) && !Char.IsControl(keyPressed))
    {
        //As above
        e.Handled = true;
        return;
    }
}

You may notice the weird function call WPFUtils.Interop.Keyboard.GetCharFromKey(e.Key) this is one of the useful functions I've collected. You can find it here.