The DataControlField.ExtractValuesFromCell(System.Collections.Specialized.IOrderedDictionary, DataControlFieldCell, DataControlRowState, bool) method is implemented by types derived from System.Web.UI.WebControls.DataControlField to associate the current field with a value, if applicable. The field/value pair is stored in the dictionary collection that is passed to the method. The DataControlField.ExtractValuesFromCell(System.Collections.Specialized.IOrderedDictionary, DataControlFieldCell, DataControlRowState, bool) method is called by the ExtractRowValues method of data controls such as System.Web.UI.WebControls.DetailsView and System.Web.UI.WebControls.GridView.

Call this method when you are writing a custom data-bound control that uses System.Web.UI.WebControls.DataControlFieldCell objects to assemble a set of cells and their associated values. Implement this method when you are writing a class derived from System.Web.UI.WebControls.DataControlField that displays user data or data-bound data. Not all derived types implement the DataControlField.ExtractValuesFromCell(System.Collections.Specialized.IOrderedDictionary, DataControlFieldCell, DataControlRowState, bool) method, because not all fields display user data. For example, the System.Web.UI.WebControls.ButtonField control displays a button and has no user data.