如何从基类访问派生类字段

Question

I created a derived class from ComboBoxItem in my Class Library.

class CustomComboBoxItem : System.Windows.Controls.ComboBoxItem
{
    public string SupplierID { get; set; }
}

And I assign each of this CustomComboxBoxItem into a ComboxBox

while (dbReader.Read())
        {
            CustomComboBoxItem BusinessNameItem = new CustomComboBoxItem();
            BusinessNameItem.Content = dbReader["BusinessName"].ToString();
            BusinessNameItem.SupplierID = dbReader["SupplierID"].ToString();

            ComboBoxControl.Items.Add(BusinessNameItem);
        }

My question now is how can I access to the SupplierID from other form?

Answer 1

Cast the ComboBoxItem to CustomComboBoxItem

ComboBoxItem item = .....
CustomBoxItem castedItem  = item as CustomBoxItem;
if(null != castedItem)
{
    var supplier = castedItem.SupplierID;
}

You can also do it in a foreach loop.

foreach(var item in ComboBoxControl.Items)
{
    CustomBoxItem castedItem  = item as CustomBoxItem;
    if(null != castedItem)
    {
        var supplier = castedItem.SupplierID;
    }
}