How to pass the PageIndex of a GridView from one page to another. : The Official Microsoft ASP.NET Forums

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banksidepoet

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862 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 06:08 PM|LINK

This isn't working, Pete.

I think the problem lies with the fact that the FindControl is looking for the ID of a HyperLink but I have a HyperLinkField within a DetailsView which, actually doesn't have an ID at all. Or is that nonsense?

In any case, what I have now is that, on first load, the GridView always goes to Page 2 and, whatever page I'm on when I click "View Large", when I return, I return to Page 2.

I've included the full markup and VB for both pages to help:

GridViewPage Markup

<%@ Page Title="Album View" Language="vb" AutoEventWireup="false" MasterPageFile="~/Resources/Master Pages/Base.Master" CodeBehind="AlbumView.aspx.vb" Inherits="Thinking.AlbumView1" %>


<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>


<asp:Content ID="Content3" ContentPlaceHolderID="MainContent" runat="server">


    <div id="albumViewAlign">
    

    <!-- Currently logged-on user -->
    <asp:Label ID="UserIdValue" runat="server" Visible="False"></asp:Label>
    

    <!-- Data Sources -->
    <asp:SqlDataSource ID="categoriesDataSource" runat="server"
        ConnectionString="<%$ ConnectionStrings:ThinkingConnectionString %>"
        SelectCommand="SELECT [CategoryID], [Name] FROM [Categories] WHERE ([UserId] = @UserId) ORDER BY [Name]">
        <SelectParameters>
            <asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text" />
        </SelectParameters>
    </asp:SqlDataSource>
    

    <asp:SqlDataSource ID="picturesDataSource" runat="server"
        CancelSelectOnNullParameter="False"
        ConnectionString="<%$ ConnectionStrings:ThinkingConnectionString %>" SelectCommand="SELECT PictureID, UploadedOn
FROM Photographs
WHERE UserId = @UserId AND (CategoryID = @CategoryID OR @CategoryID IS NULL)
ORDER BY UploadedOn DESC">
        <SelectParameters>
            <asp:ControlParameter ControlID="UserIdValue" Name="UserId"
                PropertyName="Text" />
            <asp:ControlParameter ControlID="categories" Name="CategoryID"
                PropertyName="SelectedValue" />
        </SelectParameters>
    </asp:SqlDataSource>
    

    <h2>
    View your album</h2>
        <p>
            Please note: once your account has been created, you have 28 days in which to
            purchase your images. After this time, your account will become inactive.</p>
    

    <p>
    Choose a category:
        <asp:DropDownList ID="categories" runat="server" AppendDataBoundItems="True"
            AutoPostBack="True" DataSourceID="categoriesDataSource" DataTextField="Name"
            DataValueField="CategoryID" CssClass="controlTextBox">
            <asp:ListItem Value="">-- All --</asp:ListItem>
        </asp:DropDownList>
    </p>
    

    <br />
    

    <p>
    Your photographs...
        <asp:GridView ID="gvDisplayImages" runat="server"
            EmptyDataText="There are currently no photographs in this category."
            AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False"
            DataKeyNames="PictureID" DataSourceID="picturesDataSource"  BorderColor="White"
            BorderStyle="Solid" BorderWidth="1px" RowStyle-BorderColor="#96FF32"
            RowStyle-BorderStyle="Dotted" RowStyle-BorderWidth="1px"
            CellPadding="5" PageSize="5"
            Width="800px">
            <PagerSettings Mode="NumericFirstLast" />


<RowStyle BorderColor="#96FF32" BorderWidth="1px" BorderStyle="Dotted"
                HorizontalAlign="Center"></RowStyle>
            <EmptyDataRowStyle BorderColor="#96FF32" BorderStyle="Dotted" BorderWidth="1px"
                Font-Size="Medium" ForeColor="Red" />
            <Columns>
                <asp:HyperLinkField DataNavigateUrlFields="PictureID"
                    DataNavigateUrlFormatString="PhotoView.aspx?ID={0}"
                    Text="View Large" >
                <ControlStyle ForeColor="#96FF32" />
                </asp:HyperLinkField>
                <asp:TemplateField HeaderText="Filename" InsertVisible="False"
                    SortExpression="PictureID">
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("PictureID") %>'></asp:Label>
                        .jpg
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="UploadedOn" HeaderText="Date Added"
                    SortExpression="UploadedOn" />
                <asp:ImageField DataImageUrlField="PictureID"
                    DataImageUrlFormatString="~/Photographs/{0}.jpg">
                    <ControlStyle Width="100px" />
                </asp:ImageField>
            </Columns>
            <PagerStyle ForeColor="Black" BackColor="White" />
            <SelectedRowStyle HorizontalAlign="Left" />
            <HeaderStyle ForeColor="#96FF32" HorizontalAlign="Left" />
            <EditRowStyle HorizontalAlign="Left" />
        </asp:GridView>
    </p>
    

    </div>


</asp:Content>

GridView Page VB

Public Partial Class AlbumView1
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString

        If Not Page.IsPostBack Then
            Dim index As Integer = 1
            Dim temp As String

            If Not String.IsNullOrEmpty(Request.QueryString("PageNo")) Then
                temp = Request.QueryString("PageNo").ToString()
                index = Convert.ToInt32(temp)
            End If

            gvDisplayImages.PageIndex = index
        End If


    End Sub

    'This code kindly supplied by PeteNet on ASP.NET forums
    Protected Sub gvDisplayImages_RowDataBound(ByVal sender As [Object], ByVal e As GridViewRowEventArgs)
        If e.Row.RowType = DataControlRowType.DataRow Then
            ' Find your hyperlink.
            Dim link As HyperLink = DirectCast(e.Row.FindControl("HyperLink"), HyperLink)
            link.NavigateUrl = link.NavigateUrl & "&PageNo=" & gvDisplayImages.PageIndex.ToString()
        End If
    End Sub


End Class

DetailsView Page Markup

<%@ Page Title="Photo View Page" Language="vb" AutoEventWireup="true" MasterPageFile="~/Resources/Master Pages/Base.Master" CodeBehind="PhotoView.aspx.vb" Inherits="Thinking.PhotoView" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>

<asp:Content ID="Content3" ContentPlaceHolderID="MainContent" runat="server">

    <div id="photoViewAlign">
    
    <!-- Data Sources -->
    <asp:SqlDataSource ID="pictureDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:ThinkingConnectionString %>" SelectCommand="SELECT [PictureID], [UserId], [AdminID] FROM [Photographs]WHERE ([UserId] = @UserId) ORDER BY [PictureID] DESC">
        <SelectParameters>
            <asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text" />
        </SelectParameters>
    </asp:SqlDataSource>
    
    <!-- Page -->
    
    <!-- Currently logged-on user -->
    <asp:Label ID="UserIdValue" runat="server" Visible="False"></asp:Label>
    
    <asp:DetailsView ID="dvLargeImage" runat="server" Height="50px" Width="450px" 
        AutoGenerateRows="False" DataKeyNames="PictureID" 
        DataSourceID="pictureDataSource" GridLines="None" AllowPaging="True" 
            PagerStyle-Height="40px" PagerStyle-HorizontalAlign="Center" 
            PagerStyle-VerticalAlign="Middle" CellSpacing="5" HorizontalAlign="Center">
        <PagerSettings Mode="NextPrevious" NextPageText="" 
            PreviousPageText="" NextPageImageUrl="~/Resources/Graphics/buttonNext.png" 
            PreviousPageImageUrl="~/Resources/Graphics/buttonPrevious.png" />
        <PagerStyle Font-Bold="False" ForeColor="White" Width="450px" />
        <Fields>
            <asp:HyperLinkField DataNavigateUrlFields="UserId" 
                DataNavigateUrlFormatString="AlbumView.aspx?ID={0}" 
                Text="<< Back to album.">
            <ControlStyle ForeColor="White" />
            </asp:HyperLinkField>
            <asp:ImageField DataImageUrlField="PictureID" 
                DataImageUrlFormatString="~/Photographs/{0}.jpg">
                <ControlStyle BorderColor="#96FF32" BorderStyle="Solid" BorderWidth="5px" 
                    Width="450px" />
            </asp:ImageField>
            <asp:TemplateField>
                <EditItemTemplate>
                    <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("PictureID") %>'></asp:TextBox>
                </EditItemTemplate>
                <InsertItemTemplate>
                    <asp:Label ID="Label3" runat="server" Text="You are currently viewing image: "></asp:Label>
                    <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("PictureID") %>'></asp:TextBox>
                    <asp:Label ID="Label2" runat="server" Text=".jpg"></asp:Label>
                </InsertItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label5" runat="server" Text="You are currently viewing image: "></asp:Label>
                    <asp:Label ID="Label1" runat="server" Text='<%# Bind("PictureID") %>'></asp:Label>
                </ItemTemplate>
                <ItemStyle Font-Bold="True" HorizontalAlign="Center" />
            </asp:TemplateField>
            <asp:HyperLinkField DataNavigateUrlFields="PictureID,AdminID" 
                DataNavigateUrlFormatString="PriceList.aspx?ID={0}&AdID={1}" 
                Text="Buy This Photograph">
            <ControlStyle ForeColor="#55DB32" BackColor="White" BorderColor="#96FF2B" 
                BorderStyle="Double" BorderWidth="2px" Font-Bold="False" Height="40px" 
                Width="160px" />
            <ItemStyle HorizontalAlign="Center" BackColor="Black" BorderStyle="None" 
                Font-Bold="True" ForeColor="#96FF32" Height="60px" VerticalAlign="Middle" 
                Width="450px" />
            </asp:HyperLinkField>
        </Fields>
    </asp:DetailsView>
    
    </div>

</asp:Content>

DetailsView Page VB

Imports System.Data
Imports System.Data.SqlClient

Partial Public Class PhotoView
    Inherits System.Web.UI.Page

    Dim PictureID As String

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString

        If Not Page.IsPostBack Then
            If Request.QueryString("ID") IsNot Nothing Then
                PictureID = Request.QueryString("ID").ToString()
            End If
        Else : PictureID = String.Empty
        End If


    End Sub

    Private Sub dvLargeImage_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles dvLargeImage.DataBound

        If Not String.IsNullOrEmpty(PictureID) Then
            Dim dv As DetailsView = DirectCast(sender, DetailsView)

            If dv IsNot Nothing Then
                Dim myDataRowView As DataRowView = TryCast(dv.DataItem, DataRowView)

                For iRowIndex As Integer = 0 To myDataRowView.DataView.Count - 1

                    If myDataRowView.DataView(iRowIndex).Row(0).ToString() = Request.QueryString("ID") Then

                        'found record

                        dv.PageIndex = iRowIndex

                        Exit For

                    End If

                Next

            End If
        End If

        Dim hlink As HyperLink = TryCast(dvLargeImage.Rows(0).Controls(0), HyperLink)

        If hlink IsNot Nothing Then
            If Not String.IsNullOrEmpty(Request.QueryString("PageNo")) Then
                hlink.NavigateUrl = (hlink.NavigateUrl & "&PageNo=") + Request.QueryString("PageNo")
            End If
        End If

    End Sub

End Class

I know this is a lot of code. Apologies! If you can find the time to track down where your suggestions are not working in all of this, I'd be very grateful.

Mike

Reply

PeteNet

All-Star

81342 Points

11398 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 06:35 PM|LINK

banksidepoet
I think the problem lies with the fact that the FindControl is looking for the ID of a HyperLink but I have a HyperLinkField within a DetailsView which, actually doesn't have an ID at all. Or is that nonsense?

I see what you're saying but the given code for the DetailsView would work (as long as you have the right index for the row) BUT now you'd have to apply the same type of code to find the HyperLink on the GridView. FindControl won't work on BoundFields, FYI.....and we didn't have your markup for the GridView so couldn't have given the right code either.

so, try this for the GridView in its RowDataBound event:

Dim hlink As HyperLink = TryCast(e.Row.Cells(0).Controls(0), HyperLink) 'confirm that Cells(0) is the right column for the HyperLinkField, indexes are 0-based

2nd Issue, that of defaulting to second page: because it is taking the index = 1, you could change to:

If Not Page.IsPostBack Then
            Dim index As Integer = 1
            Dim temp As String

            If Not String.IsNullOrEmpty(Request.QueryString("PageNo")) Then
                temp = Request.QueryString("PageNo").ToString()
                index = Convert.ToInt32(temp)

                gvDisplayImages.PageIndex = index

            End If


        End If

banksidepoet
I know this is a lot of code. Apologies! If you can find the time to track down where your suggestions are not working in all of this, I'd be very grateful.

yeah, time as always is at a premium ..but as long as we're getting somewhere I'm ready to help. You see its not just one issue we're dealing with.

Regards,
Peter

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banksidepoet

Participant

774 Points

862 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 06:55 PM|LINK

Thanks for your patience, Pete.

Okay, the GridView is now defaulting to Page 1, not 2, which is good.

The QueryString is not picking up the PageIndex, though: I can't see the parameters for the PageIndex in the status bar when I hover over the link (I CAN see the parameters for the Picture and UserIds I've been passing around, but no additionak, information for the PageIndex.)

When I click the "Back to Album(GridView)" link, I go back to page 1 regardless of what page I was on when I moved to the DetailsView.

I have confirmed that the "View Large" link in the GridView is the first column, so 0.

I've included the VB for the GridView page (the other code is unaltered:

GridView Page VB

Public Partial Class AlbumView1
    Inherits System.Web.UI.Page


    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load


        UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString


        If Not Page.IsPostBack Then
            Dim index As Integer = 1
            Dim temp As String


            If Not String.IsNullOrEmpty(Request.QueryString("PageNo")) Then
                temp = Request.QueryString("PageNo").ToString()
                index = Convert.ToInt32(temp)


                gvDisplayImages.PageIndex = index


            End If




        End If




    End Sub


    'This code kindly supplied by PeteNet on ASP.NET forums
    Protected Sub gvDisplayImages_RowDataBound(ByVal sender As [Object], ByVal e As GridViewRowEventArgs)
        If e.Row.RowType = DataControlRowType.DataRow Then
            ' Find your hyperlink.
            Dim hlink As HyperLink = TryCast(e.Row.Cells(0).Controls(0), HyperLink)
            hlink.NavigateUrl = hlink.NavigateUrl & "&PageNo=" & gvDisplayImages.PageIndex.ToString()






        End If
    End Sub




End Class

Reply

PeteNet

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81342 Points

11398 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 07:33 PM|LINK

banksidepoet
The QueryString is not picking up the PageIndex, though: I can't see the parameters for the PageIndex in the status bar when I hover over the link (I CAN see the parameters for the Picture and UserIds I've been passing around, but no additionak, information for the PageIndex.)

...still explainable: I would think that the RowDataBound is not even firing (is it?) ....if not, you're not debugging! :) which you should!

try changing to:

Protected Sub gvDisplayImages_RowDataBound(ByVal sender As [Object], ByVal e As GridViewRowEventArgs) Handles gvDisplayImages.RowDataBound

banksidepoet
When I click the "Back to Album(GridView)" link, I go back to page 1 regardless of what page I was on when I moved to the DetailsView.

the above might be the reason.

Regards,
Peter

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banksidepoet

Participant

774 Points

862 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 07:51 PM|LINK

We're mearly there. That solved the problem of there being no PageNo parameter in the querystring from GridView to Details View.

Sorry for not debugging: wrists slapped; I deserve it! Fact is I don't know how but... another thread.

One last hurdle: the DetailsView to GridView link does not contain the PageNo parameter and, whatever page I pass forwards, I'm always on page 1 when I come back.

Mike

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PeteNet

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81342 Points

11398 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 08:25 PM|LINK

banksidepoet
Sorry for not debugging: wrists slapped; I deserve it! Fact is I don't know how but... another thread.

Actually, that is very important, even for this thread. go through this one: http://www.beansoftware.com/ASP.NET-Tutorials/debuging-Breakpoints.aspx

banksidepoet
One last hurdle: the DetailsView to GridView link does not contain the PageNo parameter and, whatever page I pass forwards, I'm always on page 1 when I come back.

In the Databound event you set the pageindex and exit, does the code for the HyperLink execute? keep a break-point there and see.

Else it must not be finding the HyperLink. you would have to debug this one.

Regards,
Peter

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banksidepoet

Participant

774 Points

862 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 08:49 PM|LINK

Thanks for the link. Will follow that up tomorrow.

I've done my best, for now, with the breakpoint: set here... "If hlink is Not Nothing Then"

When I debug, the Autos window reports the value of hlink at this point as "Nothing".

The HyperLinkField is, however, Row(0) so not getting why it isn't finding it.

Mike

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PeteNet

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81342 Points

11398 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 25, 2010 11:22 PM|LINK

Mike,

I could do a quick debug for you, and here's what will find your HyperLink:

Dim hlink As HyperLink = DirectCast(dvLargeImage.Rows(0).Controls(1).Controls(0), HyperLink)

Hope now you could get all the pieces to work.

Regards,
Peter

Marked as answer by decker dong - msft on Jun 01, 2010 01:02 AM

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Decker Dong ...

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118619 Points

18779 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 26, 2010 01:32 AM|LINK

All in all, I think you can really try this:

1) In the Gridview, please make the Details link (the link which you click will guide to another page to see a larger image) into a common HTML

link, like <a>

2) Your link should be this:

<a href='<%#string.Format("LargerPicture.aspx?id={0}&pageindex={1}",Eval("ImageId"),Page.GridView1.PageIndex%>'>Details</a>

3) When you go to LargerPicture.aspx, in the Back button, please say this:

Response.Redirect("Main.aspx?pageIndex="+Request["pageindex"]);

4) In the Main.aspx, do this:

if(!IsPostBack)

{

GridView.DataSource = xxx;

GridView.DataBind();

if(string.IsNullOrEmpty(Request["pageindex"]))

{

GridView.PageIndex = Convert.ToInt32(Request["pageindex"]);

}

Reply

banksidepoet

Participant

774 Points

862 Posts

Re: How to pass the PageIndex of a GridView from one page to another.

May 26, 2010 06:29 AM|LINK

To Pete.

That's sorted it!

Thank you very much for all that effort. I've learned quite a lot from your answers. I will be reading that article on debugging today: you're right, it is essential to at least locate a problem even if the solution is still a little advanced.

Thanks again,

Mike

Edited by banksidepoet on May 26, 2010 06:29 AM
Edited by decker dong - msft on Jun 01, 2010 01:02 AM

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banksidepoet

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PeteNet

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banksidepoet

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