Question

I want to go through all the check boxes in form.tab and mark them as not selected. I found this was the right decision:

     foreach (Control c in this.Controls)
     {
         CheckBox cb = c as CheckBox;
         if (cb! = null & & cb.Checked)
         {
            cb.Checked = false;
         }
     }

But it does not work! And I do not understand why. I watched the debugger and cb is null. Why can this be? Where did I go wrong?

Answer 1

Try changing the first line from:

this.Controls

to

this.tab.Controls

Your current code is looping though the controls directly on the form. You need to loop through the controls on the tab.