DevCity.NET :: Using ASP.NET DataGrid Web Server Control. Page 3

Sorting is quite an important built-in feature of DataGrid. It is really easy to implement a sorting functionality in DataGrid. To enable sorting in DataGrid you need to:

add AllowSorting="True" attribute for DataGrid
set SortExpression attribute from TemplateColumn element is equal to name of column in theDataTable.
add code in DataGrid.SortCommand Event handler to customize ascending and descending sorting:

Private Sub ProductsDataGrid_SortCommand(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.DataGridSortCommandEventArgs) _
Handles ProductsDataGrid.SortCommand
   If Not ProductsDataGrid.Attributes(SortExpressionAttribute) Is Nothing Then

     Dim currectSortExpression As String = _
     ProductsDataGrid.Attributes(SortExpressionAttribute).ToString()

     If currectSortExpression.StartsWith(e.SortExpression.ToString()) Then

       If Not currectSortExpression.EndsWith(DescSortOrder) Then
         ProductsDataGrid.Attributes(SortExpressionAttribute) = _
         String.Concat(currectSortExpression, DescSortOrder)
       Else
         ProductsDataGrid.Attributes(SortExpressionAttribute) = _
         currectSortExpression.Substring(0, _
         currectSortExpression.Length - DescSortOrder.Length)
       End If
     Else
       ProductsDataGrid.Attributes(SortExpressionAttribute) = _
       e.SortExpression.ToString()
     End If
  Else
    ProductsDataGrid.Attributes(SortExpressionAttribute) = _
    e.SortExpression.ToString()
  End If

  SortDataBind()
End Sub

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DataGrid Paging

When you display quite large amounts of data, it is not convenient to scroll it. DataGrid proposed a solution for this situation - built-in paging feature.
To enable paging in DataGrid you need to:

add AllowPaging="True" attribute for DataGrid
specify PagerStyle-Mode attribute for customizing paging mode.
Add PagerStyle element like this:

<PagerStyle NextPageText="Next" PrevPageText="Prev" HorizontalAlign="Center"         
CssClass="PagingText"></PagerStyle>

Set PageSize attribute which means number of items to display on a single page of the DataGrid control
Add code in the DataGrid.PageIndexChanged Event handler:

Private Sub ProductsDataGrid_PageIndexChanged(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) _
Handles ProductsDataGrid.PageIndexChanged
    ProductsDataGrid.EditItemIndex = -1
    ProductsDataGrid.CurrentPageIndex = e.NewPageIndex
    BindDataGrid()
End Sub

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