Gets or sets a value that determines whether or not just the new values are passed to the Update method or both the old and new values are passed to the Update method.
Assembly: System.Web (in System.Web.dll)
This property determines whether parameters for old and new values are applied to the method specified by the UpdateMethod property. For example, if the method that is specified by the SelectMethod property returns a DataTable control with the columns Name and Number, and the property is set to the OverwriteChanges field, parameters are created for Name and Number for the Update method. If the property is set to the CompareAllValues value, parameters are created for Name, Number, original_Name, and original_Number. (The exact name of the parameters for the original values depends on the OldValuesParameterFormatString property.) The ObjectDataSource then determines whether the method that is specified in the UpdateMethod property has parameters that match.
Concurrency control is a technique that data stores use to control how data is read and changed in the store when multiple clients are accessing and manipulating the same data. For example, one client reads data and presents it to a user, while another client reads the same data and presents it to a different user. If both users update the data and submit it to the data storage, an unexpected result might occur, because both clients might provide different values for the same data. This is considered a conflict. By setting the property to the CompareAllValues value, the Update method can then compare the old and new values to the original data source to detect conflicts and handle them as necessary.