Programmatic button click throws 'System.StackOverflowException' exception

Crazyd22 picture Crazyd22 · Feb 16, 2010 · Viewed 35.5k times · Source

I have written a WinForms program in C#.Net to click a button programmatically within a password form.

Form1 loads and shows Form2 as a dialogue box.

The application will close if DialogResult is anything other that DialogResult.OK.

So far I have a button click event, which is coded as follows:

 if (txtpass.Text == "")
            {
                MessageBox.Show("You need to enter a password", "Password", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
                txtpass.Focus();
            }
            else
            {
                if (txtpass.Text == "1234")
                {
                    radButton1.DialogResult = DialogResult.OK;
                    radButton1.PerformClick();
                }
                else
                {
                    MessageBox.Show("Password Incorrect", "Password", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    txtpass.Text = "";
                    txtpass.Focus();
                }
            }

I use radButton1.PerformClick();, but running the program gives me the following message:

An unhandled exception of type 'System.StackOverflowException' occurred in mscorlib.dll

I'm unsure what is causing this exception to throw.

Answer

jjnguy picture jjnguy · Feb 16, 2010

Edit Not a guess. Telling the button to click itself from within itself is most definitely causing an infinite loop. This causes the method to get called over and over, filling up the stack and causing it to overflow.

My guess is that calling PerformClick() is causing the current method you posted to get called again, thus causing an infinite call loop and resulting in a StackOverflowException.

To prevent this, you need to fix the logic somewhere in your code so that:

if (txtpass.Text == "1234")

evaluates to false and the click method doesn't get called over and over. You can probably achieve this by setting txtpass.Text = "" right before you cause it to click itself again.