This exception is thrown when you try to access a null value in a column of a strongly typed DataSet . This exception isn't generated by the .NET runtime. Instead, the strongly typed DataSet class catches an System.InvalidCastException and then throws a StrongTypingException to notify your code of the problem. This code takes place in the get property accessor for a strongly typed DataRow .

public class StrongTypingException : DataException {
// Public Constructors
   public StrongTypingException(  );  
   public StrongTypingException(string s, Exception innerException);
// Protected Constructors
   protected StrongTypingException(System.Runtime.Serialization.SerializationInfo info, 
        System.Runtime.Serialization.StreamingContext context);
}

Hierarchy

System.Object System.Exception(System.Runtime.Serialization.ISerializable) System.SystemException DataException StrongTypingException