This short 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 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.
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.
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.
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
NextThe updated data can then be displayed in a DataGrid control
in the usual way.
Listing 4
'Bind datatable to datagrid
DataGrid1.DataSource = MyDataTable
DataGrid1.DataBind()
