Oh Indian

ASP.NET - Sorting Provision in Grid View

1. Choose the GridView. Press F4 to make the properties window visible. Make the AllowSorting property to True.
   
   
2. Open the GridView Tasks Menu and set SortExpression for each and every field to which, we need to have sorting provision. We will normally set the DataField Name itself in the SortExpression property as shown in the sample below.
   
   
   
3. We normally use two hidden fields to keep track of the Sorting Field and Sorting Direction. This is necessary. This kind of practice will lead avoid problems in sorting along with Paging. So add two hidden fields namely : hfSortField and hfSortDirection. By default set the value property in these fields to point to the default sorting fields and direction, for example, UserName and ASC.
4. Make sure to assign the required datasource to the Gridview property through code. If you don't know how to do this, please refere to Listing of Records in Grid View.
5. Additionally add the following code in the Sorting event of the Gridview.
   

   Protected Sub gvList_Sorting(ByVal sender As Object, _
       ByVal e As System.Web.UI.WebControls.GridViewSortEventArgs) _
               Handles gvList.Sorting
       hfSortField.Value = e.SortExpression
       hfSortDirection.Value = e.SortDirection
       LoadData()
   End Sub
   

6. Now the LoadDatA() procedure will have the following changes.
   

   Private Sub LoadData()
       Try
           Dim Sql As String
           ' Here you may extract records from any
           ' table from your database.
           Sql = "Select * From Users " & _
                 " Order By " & hfSortField.Value & " " & _
                                hfSortDirection.Value
           Dim dt As DataTable
           dt = GetDataTable(Sql)
   
           ' These following code is importat to bind  
           ' the records to the Grid View.
           gvlist.DataSource = dt
           gvlist.DataBind()
       Catch ex As Exception
           ShowError(ex)
       End Try
   End Sub
   

7. Run to view the result.