Programming Skill Tester (Problem) v2.0

If you haven't read the first problem do so know to catch up to speed. Now then, how do I go about clearing these check boxes? I tried using the same approach that @colithium told me to use for checking the state of all the check boxes, but when I ran the program and clicked clear I got the following runtime error:

Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.CheckBox'.

From stackoverflow

• Set CheckBox.Checked to false. If that's not what you need, please provide more information in the question.

• I am guessing you are running a foreach over all your controls and forgot to look if the control is actually a checkbox.

  foreach (Control c in this.Controls) {
      CheckBox cb = c as CheckBox;
      if (cb!=null) {
          //do your logic
      }
  }
  

• I assume your method looks something like this:

  private void clearButton_Click(object sender, EventArgs e)  
  {  
      CheckBox cb = (CheckBox)sender;  
      cb.Checked = false;  
  }
  

  In this case, the "Sender" is the clear button, not a check box. Borrowing from Stormenet's answer:

  private void clearButton_click(object sender, EventArgs e)  
  {    
      foreach (Control c in this.Controls)   
      {  
          CheckBox cb = c as CheckBox;  
          if (cb != null)  
          {  
              cb.Checked = false;  
          }
      }
  }