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Changing Data in an ADO.NET DataTable Using AcceptChanges Method
This article describes how to use the AcceptChanges method of the DataRow class. The method is invaluable if you need to change data in an ADO.NET DataTable object before displaying it in the web browser. The procedure described here works regardless of where the data in the DataTable object was populated from. In this particular example, the data is modified in a DataTable that is populated from static data, but it can just as easily be used to change data derived from a database.
Creating the ADO.NET data source
In this particular example, the DataTable containing the data to be modified is created and populated within code, but the technique could also be applied to a DataTable populated from a database.
This VB.NET code is used to create the DataTable object called MyDataTable, and populate it with four data columns.
Code Listing 1
'Create a datatable Dim MyDataTable As NewDataTable("MyDataTable") MyDataTable.Columns.Add(New DataColumn("UserID",System.Type.GetType("System.Int32"))) MyDataTable.Columns.Add(NewDataColumn("FirstName",System.Type.GetType("System.String"))) MyDataTable.Columns.Add(NewDataColumn("LastName",System.Type.GetType("System.String"))) MyDataTable.Columns.Add(New DataColumn("PhoneNumber",System.Type.GetType("System.String")))
Once the DataTable object has been created and its columns have been defined, data rows can be added to the DataTable. In the example code below, a new row is added to the DataTable object MyDataTable.
Code Listing 2
'Populate the datatable with a data row Dim DataRow1 As DataRow = MyDataTable.NewRow() DataRow1("UserID") = 1 DataRow1("FirstName") = "Fred" DataRow1("LastName") = "Jones" DataRow1("PhoneNumber") = "5542" MyDataTable.Rows.Add(DataRow1)
Once the DataTable object has been instantiated and populated with data, the object can be iterated. In the VB.NET sample code below, the row containing the value of "1" for the UserID column has the value of the PhoneNumber column changed to "5643." Calling the AcceptChanges() method on the current DataRow object then causes this change to be made to the row in the MyDataTable DataTable.
Code Listing 3
'Iterate through datatable Dim MyDataRow As DataRow For Each MyDataRow In MyDataTable.Rows If Convert.ToInt32(MyDataRow("UserID")) =1 Then MyDataRow("PhoneNumber") ="5643" MyDataRow.AcceptChanges() End If Next
The updated data can then be displayed in a DataGrid control in the usual way.
Code Listing 4
'Bind datatable to datagrid DataGrid1.DataSource = MyDataTable DataGrid1.DataBind()