Question

I am using the following code to check for a null text-box, and, if it is null, skip the copy to clipboard and move on to the rest of the code.

I don’t understand why I am getting a “Value cannot be NULL” exception. Shouldn’t it see the null and move on without copying to the clipboard?

private void button_Click(object sender, EventArgs e)
{
    if (textBox_Results.Text != null) Clipboard.SetText(textBox_Results.Text);            

    //rest of the code goes here;
}

Answer 1

You should probably be doing your check like this:

if (textBox_Results != null && !string.IsNullOrWhiteSpace(textBox_Results.Text))

Just an extra check so if textBox_Results is ever null you don’t get a Null Reference Exception.