NullReferenceException while transferring the selected items from one ComboBox to another

Question

I am trying to transfer the selected items of one combo box to another using following code:

ComboBoxItem shift1Driver = new ComboBoxItem(); 
shift1Driver.Text = (comboBoxDriverShift1.SelectedItem as ComboBoxItem).Text;
shift1Driver.Value = (comboBoxDriverShift1.SelectedItem as ComboBoxItem).Value.ToString();
comboBoxAccountsDriverName.Items.Add(shift1Driver);

The ComboBoxItem class is user-defined and used to store combo box text and values together.

public class ComboBoxItem
   {
       public ComboBoxItem()
       {
           Text = "ComboBoxItem1";
           Value = "ComboBoxItem1";
       }
       public string Text { get; set; }
       public object Value { get; set; }

       public override string ToString()
       {
           return Text;
       }
   }

But the code is throwing NullReferenceException and I am unable to find a reason for it. The values are being fetched like this from ComboBox: But not assigning them to ComboBoxItem's object shift1Driver. Please help.

Answer 1

As you indicated in the comments that the type of your SelectedItem is DataRowView you have no cast available. Instead build your type ComboBoxItem manually like so:

var rowView = (DataRowView) comboBoxDriverShift1.SelectedItem;  // cast 
ComboBoxItem shift1Driver = new ComboBoxItem {
     Text = rowView[1].ToString(),
     Value = rowView[0]
};
comboBoxAccountsDriverName.Items.Add(shift1Driver);

Or a little bit more condensed:

comboBoxAccountsDriverName.Items.Add(new ComboBoxItem {
     Text = ((DataRowView) comboBoxDriverShift1.SelectedItem)[1].ToString(),
     Value = ((DataRowView) comboBoxDriverShift1.SelectedItem)[0]
});