C#

protected override int FindCore(PropertyDescriptor property, object key)
{

    // Specify search columns
    if (property == null) return -1;

    // Get list to search
    List<T> items = this.Items as List<T>;

    // Traverse list for value
    foreach (T item in items)
    {

        // Test column search value
        string value = (string)property.GetValue(item);

        // If value is the search value, return the
        // index of the data item
        if ((string)key == value) return IndexOf(item);
    }
    return -1;
}