如果未选择单选按钮，如何停止计算程序？

Question

I'm really new to programming. C# is the first class I've taken and I'm stuck on this a project. We had to create a program that will calculate the cost of workshop after selecting a workshop radiobutton and a location radio button. I've got everything working the way it's supposed to except for one thing.

Let's say you select a workshop, but you don't select a location. I have it to where a MessageBox will show up saying to "select a location," but how do I stop the program from calculating if this happens? As of now, it will just calculate and give the location amount 0. I need it to not calculate at all.

public partial class frmWorkshopSelector : Form
{

    public frmWorkshopSelector()
    {
        InitializeComponent();
      }

    private void btnExit_Click(object sender, EventArgs e)
    {
        this.Close();     //When clicking the exit button, the program will close
    }

    private void btncalc_Click(object sender, EventArgs e)
    {
        int wsregistration = 0;
        int lcost = 0;
        const decimal DAYS = 3;


        //For the following if statements, depending on what workshop and location is selected,
        //their correstponding registration and lodging fees will be displayed

        {
            if (rbtHandlingStress.Checked == true)
            {
                wsregistration = 1000;
            }
            else if (rbtSupervisionSkills.Checked == true)
            {
                wsregistration = 1500;
            }
            else if (rbtTimeManagement.Checked == true)
            {
                wsregistration = 800;
            }

            else
            MessageBox.Show("Please Select a Workshop");
            lblTotalCost.Text = "";
            lblLodgingCost.Text = "";
            lblRegistrationCost.Text = "";
        }

        {
            if (rbtAustin.Checked == true)
            {
                lcost = 150;
            }
            else if (rbtChicago.Checked == true)
            {
                lcost = 225;
            }
            else if (rbtDallas.Checked == true)
            {
                lcost = 175;
            }
            else
            {
                MessageBox.Show("Please Select a Location");
                lblRegistrationCost.Text = " ";
                lblTotalCost.Text = " ";
                lblLodgingCost.Text = " ";
            }
        }

        lblRegistrationCost.Text = wsregistration.ToString("C");
        lblLodgingCost.Text = lcost.ToString("C");
        lblTotalCost.Text = (wsregistration + (lcost * DAYS)).ToString("C");

    }

    private void btnReset_Click(object sender, EventArgs e)
    { 
        //unchecks all radio buttons as well as clears out the previous calculations
        lblRegistrationCost.Text = "";
        lblLodgingCost.Text = "";
        lblTotalCost.Text = "";
        rbtHandlingStress.Checked = false;
        rbtSupervisionSkills.Checked = false;
        rbtTimeManagement.Checked = false;
        rbtAustin.Checked = false;
        rbtChicago.Checked = false;
        rbtDallas.Checked = false;
    }
}

Answer 1

You have to exit from the method. Added return statement in else block.

private void btncalc_Click(object sender, EventArgs e)
{
    int wsregistration = 0;
    int lcost = 0;
    const decimal DAYS = 3;


    //For the following if statements, depending on what workshop and location is selected,
    //their correstponding registration and lodging fees will be displayed
    if (rbtHandlingStress.Checked == true)
    {
        wsregistration = 1000;
    }
    else if (rbtSupervisionSkills.Checked == true)
    {
        wsregistration = 1500;
    }
    else if (rbtTimeManagement.Checked == true)
    {
        wsregistration = 800;
    }

    else
    {       
        lblTotalCost.Text = "";
        lblLodgingCost.Text = "";
        lblRegistrationCost.Text = "";
        MessageBox.Show("Please Select a Workshop");
        return;
    }


    if (rbtAustin.Checked == true)
    {
        lcost = 150;
    }
    else if (rbtChicago.Checked == true)
    {
        lcost = 225;
    }
    else if (rbtDallas.Checked == true)
    {
        lcost = 175;
    }
    else
    {       
        lblRegistrationCost.Text = " ";
        lblTotalCost.Text = " ";
        lblLodgingCost.Text = " ";
        MessageBox.Show("Please Select a Location");
        return;
    }

    lblRegistrationCost.Text = wsregistration.ToString("C");
    lblLodgingCost.Text = lcost.ToString("C");
    lblTotalCost.Text = (wsregistration + (lcost * DAYS)).ToString("C");
}

Answer 2

writing a "return" anywhere within the function exits that function, maybe after you show the message box to enter location, you type

return;

and this should do the job.

Answer 3

Just Add return statement in your code after showing the message box like below

public partial class frmWorkshopSelector : Form
{

    public frmWorkshopSelector()
    {
        InitializeComponent();
      }

    private void btnExit_Click(object sender, EventArgs e)
    {
        this.Close();     //When clicking the exit button, the program will close
    }

    private void btncalc_Click(object sender, EventArgs e)
    {
        int wsregistration = 0;
        int lcost = 0;
        const decimal DAYS = 3;


        //For the following if statements, depending on what workshop and location is selected,
        //their correstponding registration and lodging fees will be displayed

        {
            if (rbtHandlingStress.Checked == true)
            {
                wsregistration = 1000;
            }
            else if (rbtSupervisionSkills.Checked == true)
            {
                wsregistration = 1500;
            }
            else if (rbtTimeManagement.Checked == true)
            {
                wsregistration = 800;
            }

            else
            MessageBox.Show("Please Select a Workshop");
            lblTotalCost.Text = "";
            lblLodgingCost.Text = "";
            lblRegistrationCost.Text = "";
            return;
        }

        {
            if (rbtAustin.Checked == true)
            {
                lcost = 150;
            }
            else if (rbtChicago.Checked == true)
            {
                lcost = 225;
            }
            else if (rbtDallas.Checked == true)
            {
                lcost = 175;
            }
            else
            {
                MessageBox.Show("Please Select a Location");
                lblRegistrationCost.Text = " ";
                lblTotalCost.Text = " ";
                lblLodgingCost.Text = " ";
                return;
            }
        }

        lblRegistrationCost.Text = wsregistration.ToString("C");
        lblLodgingCost.Text = lcost.ToString("C");
        lblTotalCost.Text = (wsregistration + (lcost * DAYS)).ToString("C");

}


    private void btnReset_Click(object sender, EventArgs e)
    { //uncheks all radio buttons as well as clears out the previous calculations
        lblRegistrationCost.Text = "";
        lblLodgingCost.Text = "";
        lblTotalCost.Text = "";
        rbtHandlingStress.Checked = false;
        rbtSupervisionSkills.Checked = false;
        rbtTimeManagement.Checked = false;
        rbtAustin.Checked = false;
        rbtChicago.Checked = false;
        rbtDallas.Checked = false;
    }
}

}