Question

As far as I know, combo-boxes in Windows Forms can only hold one value. I needed a text and an Index so i created this little class:

public class ComboboxItem { 
    public string Text { get; set; } 
    public object Value { get; set; } 
    public override string ToString() 
    { 
        return Text; 
    }
}

I add an Item to the combo-box as following:

ComboboxItem item = new ComboboxItem()
{
    Text = select.Item1,
    Value = select.Item2
};

this.comboBoxSelektion.Items.Add(item);

Now to my question: How do I set the combobox to specific item?
I tried this, but that didn’t work:

this.comboBoxSelektion.SelectedItem = new ComboboxItem() { Text = "Text", Value = 1};

Answer 1

The last code sample you provided doesn’t work, because the item in the ComboBox and the item you create via new are different instances (= memory references) which are not the same (two different memory pointers) even though they are equal (their members have the same values). Just because two objects contain the same data doesn’t make them the same object – it makes them two different objects that are equal.

That’s why usually there’s a big difference between o1 == o2 and o1.Equals(o2);.

Examples:

ComboboxItem item1 = new ComboBoxItem() { Text = "Text", Value = 1 };
ComboboxItem item2 = new ComboBoxItem() { Text = "Text", Value = 1 };
ComboboxItem item3 = item1;

item1 == item2      => false
item1.Equals(item2) => true, if the Equals-method is implemented accordingly
item1 == item3      => true!! item3 "points to the same object" as item1
item2.Equals(item3) => true, as above

What you need to do is find the same instance you added to the list. You could try the following:

this.comboBoxSelektion.SelectedItem = (from ComboBoxItem i in this.comboBoxSelektion.Items where i.Value == 1 select i).FirstOrDefault();

This selects the first item from the items assigned to the ComboBox the value of which is 1 and sets it as the selected item. If there’s no such item, null is set as the SelectedItem.