Using Directives or Assembly Reference

Question

I added some buttons to a Form, but doubled clicked the wrong one and that took me to the code editor.

I decided to delete the generated code that resulted from clicking the wrong button. I did a rebuild and ended up getting an error:

Error 1 'xxxxx' does not contain a definition for 'xxxxx' and no extension method 'subtraction_Checked' accepting a first argument of type 'xxxx' could be found (are you missing a using directive or an assembly reference?)

How do I resolve this?

Answer 1

When you double click on button , it creates an event handler in designer generated code as:

this.button1.Click += new System.EventHandler(this.button1_Click);

and in code editor you will see this:

private void button1_Click(object sender, EventArgs e)
{
}

Now, if you remove only the handler, you will get an error. To resolve this you need to remove the event from designer generated code ie this.button1.Click += new System.EventHandler(this.button1_Click);

Same goes for checkboxes, textboxes and other controls as well.

Answer 2

You have a control on your Form. It called "subtraction". If it is a checkbox, and if you double click on it your developing program auto-generates the event-handler for Checked event. It makes a code in your form's code (the void) and in yor designer file (the calling of the void). I think you deleted only the void. You must go to the designer file and telete the event calling. It looks like:

this.subtraction.Checked += new System.EventHandler(this.subtracion_Checked);

You must delete this line.