DataTable RejectChanges

The DataTable’s RejectChanges() method rolls back the changes done to the DataRow.

Now let us see with an example, on how the rowstate property gets affected by calling the RejectChanges() method of the DataTable.

Let us add a new row to a DataTable, and perform various operations on the row to observer the change in the RowState of the row.

// Fill the DataTable with your own logic

// Here we will fill the table by calling the Domain class.

clsEmployee objEmp = new clsEmployee();

DataTable dtEmployee = objEmp.GetEmployeeList();
DataRow drEmp;

//

// Add a new Row and perform data changes

drEmp = dtEmployee.NewRow(); // RowState - Detached

dtEmployee.Rows.Add(drEmp);  // RowState - Added

dtEmployee.RejectChanges();  // RowState - Detached

drEmp["ID"] = 3134;          // RowState - Detached

drEmp.Delete();              // RowState - Detached

drEmp = dtEmployee.NewRow(); // RowState - Detached

dtEmployee.Rows.Add(drEmp);  // RowState - Added

dtEmployee.AcceptChanges();  // RowState - Unchanged

drEmp["ID"] = 3134;          // RowState - Modified

dtEmployee.RejectChanges();  // RowState - Unchanged

drEmp = dtEmployee.NewRow(); // RowState - Detached

dtEmployee.Rows.Add(drEmp);  // RowState - Added

dtEmployee.AcceptChanges();  // RowState - Unchanged

drEmp["ID"] = 3134;          // RowState - Modified

dtEmployee.AcceptChanges();  // RowState - Unchanged

drEmp.Delete();              // RowState - Deleted

dtEmployee.RejectChanges();  // RowState - Unchanged

Calling RejectChanges, after Adding a new row removes the row from the DataTable
Calling RejectChanges, after Modifying a row rolls back the state of the row to Unchanged
Calling RejectChanges, after Deleting a row rolls back the state of the row to Unchanged

Notice that, every time you call the DataTable’s RejectChanges() method, the changes are rolled back either to the initial state or to the state when AcceptChanges() was last called on the DataTable.

The following are the changes of RowState of the DataRows in the DataTable, before and after calling the DataTable’s AcceptChanges() method.

RowState before calling RejectChanges()	RowState after calling RejectChanges()	Impact on the Row
Added	Detached	Row is Permanently Removed from the DataTable
Modified	Unchanged	Data modifications to the row are rolled back.
Deleted	Unchanged	Row is retained in the DataTable

The RejectChange() method can also be called on the individual DataRows in the DataTable, calling the DataTable’s RejectChanges() method, will rollback the changes of all the DataRows in the DataTable.

To know more on the DataTable’s AcceptChanges() method, refer the post DataTable AcceptChanges.


Related Posts
DataRow RowState
DataTable AcceptChanges
DataTable RejectChanges
Get new rows in a DataTable / DataGridView in C# Windows Forms
Get Modified rows in a DataTable / DataGridView in C# Windows Forms
Get Deleted rows in a DataTable / DataGridView in C# Windows Forms