Having a problem using switches in C#

Question

I'm getting the error "A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type" in my code at the line,

switch (job_selecter.SelectedValue)

Here's my code:

    private void start()
    {
        switch (job_selecter.SelectedValue)
        {
            case 0:
                head_seal_label.Text = "Ravager's Seal: Head (8)";
                break;
        }
    }

Could anyone tell me why this is happening and how I can fix it? Thanks!

Answer 1

job_selecter.SelectedValue is probably an object.

 private void start()
    {
        int index = (int)job_selecter.SelectedValue;
        switch (index )
        {
            case 0:
                head_seal_label.Text = "Ravager's Seal: Head (8)";
                break;
        }
    }

Answer 2

It seems like what you really want to do is this:

switch(job_selecter.SelectedIndex)
{
    case 0:
        // do whatever
        break;

    default:
        // handle default case
        break;
}

You've noted in one of your responses that casting SelectedValue to string or int or whatever can cause a null reference exception if you then use it in a switch--which makes perfect sense, because it's perfectly legal for a combo box to have nothing selected, and you're going to need to account for that case. If you switch on SelectedIndex, handling -1 will allow you to handle a case of "no selection" specifically.

Of course, it's worth pointing out that switching on SelectedIndex only makes sense if the combo box contains a known, unchanging set of values. Adding or removing values will potentially cause the indices of everything in the box to change, thus breaking the switch.

Answer 3

SelectedValue is an object. cast it to an int in the switch.

Answer 4

You might have meant to use "SelectedIndex" property (a zero based number corresponding to your selection in combo OR a -1 when nothing is selected):

switch (job_selecter.SelectedIndex)
{
    case 0:
        head_seal_label.Text = "Ravager's Seal: Head (8)";
        break;
    // other cases for other Indices
    case -1:
    default:
        // handle nothing selected...
} 

Answer 5

You should get your SelectedIndex into an int first, to deal with this error " "A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type" in my code at the line":

int index;
if(!Int32.TryParse(job_selector.SelectedIndex.ToString(), out index))
{
    index = -1;
}
//All your other cases here    
switch(index)
{
    case 0:
        head_seal_label.Text = "Ravager's Seal: Head (8)";
        break;

    default:
        head_seal_label.Text = "Some default Value";
        break;
}