Question

I’m trying to remove selected item from ComboBox Collection:
I wrote a buttonClick:

cb01.Items.Remove(cb01.SelectedItem);.

This deletes the item, but next time I open the Form – the item appears again.
Please help.

Answer 1

Add KeyDown event for your ComboBox and then

private void cb01_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Delete)
    {
      if(cb01.SelectedIndex != -1)
         cb01.Items.Remove(cb01.SelectedItem);
    }
}

Above will remove items from comboBox but if you add items on designed time when you load the application again you can see all the items again.

check your InitializeComponent() method. you can see something like below.

 this.cb01.Items.AddRange(new object[] {
            "item1",
            "item2",
            "item13"});

when you load the application again, it will call InitializeComponent and call above method to add items.

To avoid this issue. You can use bound data source. e.g you can take items from database. and when you delete you can delete it from database. next time you load the application it only show the items in the database.