Common Function to validate keypress event for multiple texboxes in windows Form

Question

Can we created common function to check keypress event and restrict user to enter only numeric entries for multiple textboxes in windows form?

Can we create something like below:

private void txtsample1_keypress(...)
{
  call validate()
}

private void txtsample2_keypress(...)
{
  call validate()
}

public void validate()
{
  Here, validation for multiple textboxes
}

have a look here: http://stackoverflow.com/questions/3157106/keydown-event-how-to-easily-know-if-the-key-pressed-is-numeric and also it might be a good idea to check this in KeyUp rather than KeyPress ... — vidriduch, Sep 25 '14 at 15:26

score 3 · Accepted Answer · edited May 23 '17 at 12:31

Yes.

Note you probably want IsDigit(char) rather than IsNumber(char), as discussed in Difference between Char.IsDigit() and Char.IsNumber() in C#.

public void Form_Load(object sender, EventArgs e)
{
    txtsample1.KeyPress += ValidateKeyPress;
    txtsample2.KeyPress += ValidateKeyPress;
}

private void ValidateKeyPress(object sender, KeyPressEventArgs e)
{
    // sender is the textbox the keypress happened in
    if (!Char.IsDigit(e.KeyChar)) //Make sure the entered key is a number (0-9)
    {
        // Tell the text box that the key press event was handled, do not process it
        e.Handled = true;
    }
}

score 1 · Answer 2 · answered Sep 25 '14 at 15:25

Sure, you can even register the same event on all your text boxes and process them all through one.

    void txt_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!Char.IsNumber(e.KeyChar)) //Make sure the entered key is a number
            e.Handled = true; //Tells the text box that the key press event was handled, do not process it
    }

Common Function to validate keypress event for multiple texboxes in windows Form

2 Answers2