/// <summary>
/// Function called to search the model
/// for availability of the specified string.
/// </summary>
/// <param name="str">The search string</param>
/// <returns>True, if the string is contained in the model, else false</returns>
public override bool Contains(string str)
{
return(IndexName != null && IndexName.StartsWith(str, StringComparison.CurrentCultureIgnoreCase));
}