Question

I am trying to write the user login details to the Database.
When I click the submit button Im getting a NullReferenceException.
There are 4 TextBoxes
Username, Email, Password and ConfirmPassword.

protected void Button1_Click(object sender, EventArgs e)
        {
            if ((RegisterUserWizardStep.FindControl("Password") as TextBox).Text == (RegisterUserWizardStep.FindControl("ConfirmPassword") as TextBox).Text)
           {
                //call the method to execute insert to the database
                ExecuteInsert((RegisterUserWizardStep.FindControl("UserName") as TextBox).Text,
                              (RegisterUserWizardStep.FindControl("Email") as TextBox).Text,
                             (RegisterUserWizardStep.FindControl("Password") as TextBox).Text);
                Response.Write("Record was successfully added!");
                ClearControls(Page);
          }
            else
            {
                Response.Write("Password did not match");
                (RegisterUserWizardStep.FindControl("Password") as TextBox).Focus();
           }
        }

Thank you.

Answer 1

Its likely that FindControl didn’t find the control you are after, possibly because the TextBoxes are nested under another child control like a panel etc.

Instead of

if ((RegisterUserWizardStep.FindControl("Password") as TextBox).Text 

try

TextBox passwordTextBox = RegisterUserWizardStep.FindControl("Password") as TextBox;
// .. same for username and email
if ((passwordTextBox != null) && (usernameTextBox != null) ... )
{
 // Do something with the textboxes
}
// else you have a bug

This will also prevent you repeating the FindControl code on the same control (DRY principle)