Detecting a key press in a text box and receiving an overload EventHandler error message

Question

I am requiring some assistance with my C# program, where I am getting an error message for having a form where the user would enter in text into a text box. I am trying to detect if the user has pressed the Enter key, and on doing so would produce a message box with a message. However, I am trying to call the "KeyEventArgs" class which would allow me to detect the key press, but receive the following error message:

No overload for 'TextBox_KeyDown' matches delegate 'System.EventHandler'

Here is my code for the TextBox I am using:

    private void TextBox_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Enter)
        {
            MessageBox.Show("You have entered the correct key.");
        }
    }

Clicking on the error message for further details, leads me to the Designer class for the form I am using, and underlines the following text:

   this.TextBox.KeyDown += new System.EventHandler(this.TextBox_KeyDown);

have you tried changing this line if (e.KeyCode == Keys.Enter) to this if (e.KeyCodes == Keys.Enter) and I would think that would be the KeyPress_Event instead — MethodMan

keyboardP keyboardP · Accepted Answer · 2013-03-22T17:59:56

Use the KeyEventHandler instead. Also, is the name of your TextBox actually TextBox? This isn't recommended as it becomes ambiguous as to whether you're referring to an instance or the TextBox control object.

 this.TextBox.KeyDown += new KeyEventHandler(this.TextBox_KeyDown)

Your error message refers to the fact that your method's signature is (object sender, KeyEventArgs e) but the delegate you're trying to pass actually has a signature of `(object sender, EventArgs e).

Detecting a key press in a text box and receiving an overload EventHandler error message

2 Answers