Question

How to make the following extension works? I’m binding the ComboBoxe to an enum and in this case it doesn’t compile because it returns null.

public static T GetSelectedValue<T>(this ComboBox control)
{
    if (control.SelectedValue == null)
        return null;

    return (T)control.SelectedValue;
}

Note: I want it te return null (instead of default(T)). The question is that what’s the where expression that I’ve got to use?

Answer 1

Return a nullable instead of a plain T:

public static T? GetSelectedValue<T>(this ComboBox control) where T : struct
{
    if (control.SelectedValue == null)
        return null;

    return (T)control.SelectedValue;
}