Question

I want to allow the user to send his message when he press enter in the textbox.
I went to search and im using the sample codes below.

Now the problem is when i press enter, the event is triggered more than once like about 4-5 times.

Someone else suggested to use keyup. I have tried keyup, keydown and keypress. All have the same problem.
How do i prevent it from firing the event more than once?

private void tbxAnswer_TextChanged(object sender, EventArgs e)
    {
        tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);
    }

    private void tbxAnswer_KeyUp(object sender, KeyEventArgs e)
    {
        if (e.KeyValue == (char)13)
        {

            MessageBox.Show("Hello");

        }
    }

Thank you!

Answer 1

You are adding the KeyUp event handler multiple times (inside the TextChanged handler); therefore, when Enter is pressed, the handler executes multiple times.

What you want to do here is add the KeyUp handler just once, inside your form’s constructor, just after the InitializeComponent() call:

public MyForm()
{
    // other code possibly here
    InitializeComponent();

    // and now add the event handler:
    tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);
}

private void tbxAnswer_KeyUp(object sender, KeyEventArgs e)
{
    if (e.KeyValue == (char)13)
    {
        MessageBox.Show("Hello");
    }
}