ADO.NET in a Nutshell

Using Row Version Information

ADO.NET maintains up to three versions of each DataRow object. The DataAdapter reconciles changes made since the data was loaded from the data source, thereby making changes to the disconnected data permanent. Two versions of each row are maintained to allow the DataAdapter to determine how to perform the reconciliation. The Original version contains the values that were loaded into the row. The Current version contains the latest version of the data, including the changes made since the data was originally loaded. The Original version isn’t available for newly created rows.

ADO.NET also allows a row to be put into edit mode which temporarily suspends events for the row and allows the user to make multiple changes to the row without triggering validation rules. The BeginEdit( ) method of the DataRow puts the row into edit mode, while the EndEdit( ) and CancelEdit( ) methods take the row out of edit mode. AcceptChanges( ) also takes the row out of edit mode because it implicitly calls EndEdit( ), as does RejectChanges( ), which implicitly calls CancelEdit( ).

A Proposed row version is made available while the row is in edit mode and contains the changes that have been made to the row while it was in edit mode. If the EndEdit( ) method is called, the changes made are copied from the Proposed row to the Current row. If the CancelEdit( ) method is called, the values in the Proposed version are simply discarded. In either case, once the editing is completed, ...