GridView Sorting/Paging w/o a DataSourceControl DataSource (VB.NET)

This page is reproduced from this URL. Copied here for easy reference. All credits to the original author.
                                                                             ______________________

If you set AllowPaging=”true” or AllowSorting=”true” on a GridView control without using a DataSourceControl DataSource (i.e. SqlDataSource, ObjectDataSource), you will run into the following errors:

When changing the page on the GridView control:

The GridView ‘GridViewID’ fired event PageIndexChanging which wasn’t handled.

When clicking a column name to sort the column on the GridView control:

The GridView ‘GridViewID’ fired event Sorting which wasn’t handled.

As a result of not setting the DataSourceID property of the GridView to a DataSourceControl DataSource, you have to add event handlers for sorting and paging.

<%@ Page Language=”VB” %>

 

<%@ Import Namespace=”System.Data” %>

<%@ Import Namespace=”System.Data.OleDb” %>

 

<script runat=”server”>   

    Private Sub PopulatePublishersGridView()

        Dim connectionString As String = AccessConnectionString()

        Dim accessConnection As OleDbConnection = New OleDbConnection(connectionString)

 

        Dim sqlQuery As String = “SELECT [PubID], [Name], [Company Name], [Address], [City], [State], [Zip], [Telephone], [Fax], [Comments] FROM Publishers ORDER BY [Name] ASC;”

 

        Dim accessCommand As New OleDbCommand(sqlQuery, accessConnection)

 

        Dim publishersDataAdapter As New OleDbDataAdapter(accessCommand)

        Dim publishersDataTable As New DataTable(“Publishers”)

        publishersDataAdapter.Fill(publishersDataTable)

 

        Dim dataTableRowCount As Integer = publishersDataTable.Rows.Count

 

        If dataTableRowCount > 0 Then

            gridViewPublishers.DataSource = publishersDataTable

            gridViewPublishers.DataBind()

        End If

    End Sub

 

    Private Function AccessConnectionString() As String

        Dim accessDatabasePath As String = Server.MapPath(“~/App_Data/biblio.mdb”)

        Return String.Format(“Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};”, accessDatabasePath)

    End Function

 

    Private Property GridViewSortDirection() As String

        Get

            Return IIf(ViewState(“SortDirection”) = Nothing, “ASC”, ViewState(“SortDirection”))

        End Get

        Set(ByVal value As String)

            ViewState(“SortDirection”) = value

        End Set

    End Property

 

    Private Property GridViewSortExpression() As String

        Get

            Return IIf(ViewState(“SortExpression”) = Nothing, String.Empty, ViewState(“SortExpression”))

        End Get

        Set(ByVal value As String)

            ViewState(“SortExpression”) = value

        End Set

    End Property

 

    Private Function GetSortDirection() As String

        Select Case GridViewSortDirection

            Case “ASC”

                GridViewSortDirection = “DESC”

 

            Case “DESC”

                GridViewSortDirection = “ASC”

        End Select

 

        Return GridViewSortDirection

    End Function

 

    Protected Sub gridViewPublishers_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)

        gridViewPublishers.DataSource = SortDataTable(CType(gridViewPublishers.DataSource,DataTable), True)  gridViewPublishers.PageIndex = e.NewPageIndex

        gridViewPublishers.DataBind()

    End Sub

 

    Protected Function SortDataTable(ByVal pdataTable As DataTable, ByVal isPageIndexChanging As Boolean) As DataView

        If Not pdataTable Is Nothing Then

            Dim pdataView As New DataView(pdataTable)

            If GridViewSortExpression <> String.Empty Then

                If isPageIndexChanging Then

                    pdataView.Sort = String.Format(“{0} {1}”, GridViewSortExpression, GridViewSortDirection)

                Else

                    pdataView.Sort = String.Format(“{0} {1}”, GridViewSortExpression, GetSortDirection())

                End If

            End If

            Return pdataView

        Else

            Return New DataView()

        End If

    End Function

 

    Protected Sub gridViewPublishers_Sorting(ByVal sender As Object, ByVal e As GridViewSortEventArgs)

        GridViewSortExpression = e.SortExpression

        Dim pageIndex As Integer = gridViewPublishers.PageIndex

        gridViewPublishers.DataSource =  SortDataTable(CType(gridViewPublishers.DataSource,DataTable), False)

        gridViewPublishers.DataBind()

        gridViewPublishers.PageIndex = pageIndex

    End Sub

 

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

        PopulatePublishersGridView()

    End Sub

</script>

 

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>

<html xmlns=”http://www.w3.org/1999/xhtml”>

<head id=”Head1″ runat=”server”>

    <title>GridView Sorting/Paging without a DataSourceControl DataSource</title>

</head>

<body>

    <form id=”form” runat=”server”>

        <div>

            <asp:GridView ID=”gridViewPublishers” AllowPaging=”true” AllowSorting=”true” AutoGenerateColumns=”false”

                EmptyDataText=”No records found” PagerSettings-Mode=”NumericFirstLast” PageSize=”25″

                OnPageIndexChanging=”gridViewPublishers_PageIndexChanging” OnSorting=”gridViewPublishers_Sorting”

                runat=”server”>

                <AlternatingRowStyle BackColor=”LightGray” />

                <HeaderStyle BackColor=”Gray” Font-Bold=”true” Font-Names=”Verdana” Font-Size=”Small” />

                <PagerStyle BackColor=”DarkGray” Font-Names=”Verdana” Font-Size=”Small” />

                <RowStyle Font-Names=”Verdana” Font-Size=”Small” />

                <Columns>

                    <asp:BoundField DataField=”PubID” HeaderText=”Publisher ID” SortExpression=”PubID” />

                    <asp:BoundField DataField=”Name” HeaderText=”Name” SortExpression=”Name” />

                    <asp:BoundField DataField=”Company Name” HeaderText=”Company Name” SortExpression=”Company Name” />

                    <asp:BoundField DataField=”Address” HeaderText=”Address” SortExpression=”Address” />

                    <asp:BoundField DataField=”City” HeaderText=”City” SortExpression=”City” />

                    <asp:BoundField DataField=”State” HeaderText=”State” SortExpression=”State” />

                    <asp:BoundField DataField=”Zip” HeaderText=”Zip” SortExpression=”Zip” />

                    <asp:BoundField DataField=”Telephone” HeaderText=”Telephone” SortExpression=”Telephone” />

                    <asp:BoundField DataField=”Fax” HeaderText=”Fax” SortExpression=”Fax” />

                    <asp:BoundField DataField=”Comments” HeaderText=”Comments” SortExpression=”Comments” />

                </Columns>

            </asp:GridView>

        </div>

    </form>

</body>

</html>

4 thoughts on “GridView Sorting/Paging w/o a DataSourceControl DataSource (VB.NET)

  • October 3, 2007 at 8:03 am
    Permalink

    hi,

    i tried the sort algo, but i get an error.

    Unable to cast object of type ‘System.Data.DataView’ to type ‘System.Data.DataTable’.

    when i call the sortDataTable(…)

    i noticed that this method is called twice and the error occurs during the second pass.

    pls. help. tnx

    Reply
  • October 3, 2007 at 8:57 am
    Permalink

    Try calling SortDataTable this way

    Its called twice, once during Sorting and second time during page index change.

    SortDataTable(CType(gridViewPublishers.DataSource,DataTable), True)

    SortDataTable(CType(gridViewPublishers.DataSource,DataTable), False)

    I have also modified the parameters for SortDataTable declaration. Let me know if you still have problem.

    Reply
  • December 16, 2007 at 9:07 pm
    Permalink

    I was having the same problem Kyukee was having.

    I used the ToTable method to ensure that the DataSource was always a table.

    The line of code I modified was:
    grdContacts.DataSource = SortDataTable(CType(grdContacts.DataSource, DataTable), False).ToTable

    Hope that helps you. Thanks for converting this code to VB!

    Reply

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: