Instead of specifying several parameters that are passed to the Update, Insert, and Delete methods, you can create one object that aggregates several data field values. This one object is passed to the methods, instead of several parameters.
The default behavior of an ObjectDataSource control that is bound to a data-bound control is that the data-bound control creates a Parameter object for each parameter in the data source. If the business object has many fields, the resulting method also has many fields. The DataObjectTypeName property allows you to specify a type that has a property for each data field. Then, instead of passing several parameters to the method, the runtime creates one object and sets all of its properties. This one object is added to the parameters collection for the method call.
The type that is specified by the DataObjectTypeName property must have a default constructor that has no parameters, so the ObjectDataSource control can create an instance of the type. The type must also have settable properties that allow the ObjectDataSource control to populate the object with values that are passed from the data-bound control. The property names on the ObjectDataSource control are expected to exactly match the parameter names of values that are passed by the data-bound control.
When the DataObjectTypeName property is set and the ObjectDataSource control is associated with a data-bound control, the methods that are specified by the InsertMethod and DeleteMethod properties must each have one parameter of the type that is specified in the DataObjectTypeName property. If the ConflictDetection property is set to the OverwriteChanges value, the method that is specified by the UpdateMethod property must have one parameter of the type that is specified in the DataObjectTypeName property. If the ConflictDetection property is set to the CompareAllValues value, the method that is specified by the UpdateMethod property must have two parameters of the type that is specified in the DataObjectTypeName property. The first parameter contains the original values; the second parameter contains the new values.
The DataObjectTypeName property delegates to the DataObjectTypeName property of the ObjectDataSourceView that is associated with the ObjectDataSource control.