Paging with grid view

sophia · December 5th, 2009, 03:20 AM

Hello friends, I am having problem in paging with the grid view. The problem is that suppose there are N no. of pages then moving in between from page no. 1 to N-1 works fine but as soon as I move to page no. N and try to move some previous page then it generates error telling that

Code:

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

I am using VB.NET and grid view with SqlDataSource. Also using RowCommand Event to perform some task on commands.

My code is something is like this

Code:

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" GridLines ="Horizontal" EmptyDataText="Sorry,There Are No Data Records To Display." AutoGenerateColumns="False" DataKeyNames="Id" DataSourceID="SqlDataSource1">
 <Columns>
       <asp:ButtonField ButtonType="Button" CommandName="play1" HeaderText="Play" Text="Play" />
         
      <asp:BoundField DataField="SongName" HeaderText="Song Name" SortExpression="SongName" />
                          
       <asp:ButtonField ButtonType="Button" CommandName="download1" HeaderText="Download" Text="Download" />
 </Columns>
</asp:GridView>

And the code behind file is like

Code:

Protected Sub GridView1_RowCommand1(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles GridView1.RowCommand
        con.Open()
        Dim play_index_db As Integer = GridView1.DataKeys(e.CommandArgument).Values("Id").ToString() 
        Dim s As String = "select SongPath from Music where Id = " & play_index_db.ToString() 
        Dim cmd As New SqlCommand(s, con)
        Dim p As String = Convert.ToString(cmd.ExecuteScalar())
        
        If e.CommandName = "play1" Then
code goes here.................
            End If
        End If

        If e.CommandName = "download1" Then
           code goes here...........
        End If
        con.Close()
    End Sub

Error is generated on the line

Code:

Dim s As String = "select SongPath from Music where Id = " & play_index_db.ToString()

whenever I move to page No. N to some previous page.

any suggestion is respected and hope soon I'll get reply
Thank you......

Imar · December 5th, 2009, 10:54 AM

Didn't I provide an answer to that earlier? You need to look at e.CommandName and only execute your code when it makes sense. I doubt you want to select a single item every time you want to page....

Imar

sophia · December 5th, 2009, 11:17 AM

yes sir, I do not regret from what you provided earlier but still having problem in paging. I also followed the link you provided.
OK I try to put the code in the e.CommandName

Imar · December 5th, 2009, 11:27 AM

You should *check* the CommandName and only execute the code if the command name is something you expect (e.g. not Sort or Page, but one you've set yourself):

Code:

 
Protected Sub GridView1_RowCommand1(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles GridView1.RowCommand
 
  If e.CommandName = "play1" Or e.CommandName = "download1" Then
    ' Only execute your code here
  End If
End Sub

Cheers,

Imar

sophia · December 5th, 2009, 11:38 AM

love you sir, I got your message from your first post. And Now paging is working fine.
But Can you please explain why it was getting me problem when I put the code outside the e.CommandName
Please reply this one
And of course thank you.......

Imar · December 5th, 2009, 12:53 PM

I provided that answer in my first post to your original qustion (now confusingly burried somewhere else in a separate thread): Paging

The RowCommand also fires when sorting and paging. In those cases your own code doesn't make sense to fire....

Imar

sophia · December 5th, 2009, 01:01 PM

may be that, that time I was not able to understand you properly. Because sometimes we are not able to understand somethings at first time but on subsequent learning things become clear.
Anyway again thank you for replying my query.
All credit goes to you. Thank you once again sir. You really solved my query at one shot once again. Thank you..........

Imar · December 5th, 2009, 01:05 PM

Yes, I agree. That's why I am not simply supplying you with the answer, but encourage you to search the web, read articles, and experiment. It's the only way to really understand these kind of topics....

Imar

sophia · December 5th, 2009, 01:10 PM

Thank you sir for encouraging me and what ever I do. Hope one day I will also be able to think like you and be able to help others as you do.
One request
Always keep smiling
Please........
Thank you once again.