I've been trying to create a textbox that will eventually create a calculator. I'm trying to get it to ignore characters. I'm not sure where to put this function to get it to work. I currently have this function as a sample just to handle the letter e.

private void txtInput_keyPre ss(object sender, System.Windows. Forms.KeyPressE ventArgs e)
{
if (e.KeyChar == 'e')
{
...