InvalidArgument =值'18'对'SelectedIndex'无效参数名称：SelectedIndex

Question

I have a Button where I am able to save data into the database. To do that I will get the information on Combobox and on a Textbox . I got a collection of items iniside of the Combobox and cannot be changed at the moment.

Right now, I have 17 items and every time I save something it will pull to the next item using cmbID.SelectedIndex += 1; , but every time I pull to the last item from Combobox it will give me an error :

InvalidArgument=Value '18' is invalid to 'SelectedIndex' Parameter name: SelectedIndex

To solve it I've tried to use an if statement:

if (cmbID.SelectedIndex >= 18)
{
    cmbID.SelectedIndex = 1;
}

But this is not working, basically if the Combobox reach '18' it should go back to the SelectedIndex choosen by me.

Do you guys have any idea I can solve this problem?

Answer 1

You can't have index more than (item count -1) for the combobox, so

if(cmbID.SelectedIndex == (cmbID.Items.Count - 1))
{
    cmbID.SelectedIndex =1;
}else
{
    cmbID.SelectedIndex += 1;
}