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:
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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 |
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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