Question

I’m doing a project for college and have create a panel with a simple lunch menu. Each item of the menu if presented by a check box. What I wanted to happen was for the total to be changed every time a new item is checked or unchecked. This is the code I have tried using so far but it seems to freeze the program when I run it. I have tried using a while loop to constantly check if the check boxes are checked or un-checked.

There is a panel with the check boxes inside and a label at the bottom of the panel.

Am I on the right line in terms of using the while loop to check what the checked status of each check box is and update the label text accordingly?

private void plBistro_Paint(object sender, PaintEventArgs e)
        {
            //create a variable to hold the total
            double bistotal = 0.0;

            while(bistotal != 99){
                //check if they chose a ham sandwich
                if(cbHamSandwich.Checked == true){

                    //if they did add 1.20 to the value of bistotal
                    bistotal = bistotal + 1.20;
                }

            string bistotalString = Convert.ToString(bistotal);

            lblBistroTotal.Text = bistotalString;
        }
        }

Answer 1

You have an infinite loop in your code, plus the Paint event is not the place to do this calculation. You want something more like:

private void cbHamSandwich_CheckChanged (object sender, EventArgs e)
{
    CalcTotal();
}

private void CalcTotal()
{
    double bistotal = 0.0;

    if(cbHamSandwich.Checked == true)
    {
        //if they did add 1.20 to the value of bistotal
        bistotal = bistotal + 1.20;
    } 

    // more selected values to add to total

    lblBistroTotal.Text = bistotal.ToString("c");
}

Add CheckChanged events for each option that needs to change the total price.