Datalist in asp.net? ItemCommand event not firing?

Question

hi,

in my web application i have a datalist in that i am binding some images. in datalist itemcommand event i write code some code which is not firing, i mean the itemcomand event is not firing. can u help me. this is my source code

DataList control:

<asp:DataList ID="DLQuickVideos" runat="server"  RepeatColumns ="2" CellPadding="0" CellSpacing="0" OnItemCommand="DLQuickVideos_ItemCommand" >                       
     <ItemTemplate>                                        
         <asp:ImageButton ID="imgbtn" runat="server" ImageUrl='<%# "../Trailorvideos/"+ Eval("SnapShot") %>' CommandArgument='<%# Eval("video")+"|"+Eval("videoid") %>' CausesValidation="false"  Width="111px" Height="83px" BorderStyle="double" BorderWidth="4px" BorderColor="#A70202" />                                                                    
     </ItemTemplate>
</asp:DataList> 

Event Handler:

protected void DLQuickVideos_ItemCommand(object source, DataListCommandEventArgs e)
{        
    try
    {
        string eval = e.CommandArgument.ToString();
        int k = eval.IndexOf("|");
        videoname = eval.Substring(0, k);
        videoid = eval.Substring(k + 1);
        string move = Request.QueryString["movie"].ToString();

        if (Request.Browser.Browser == "IE")
        {
            dvplayer.InnerHtml = "<object id='player' classid='clsid:D27CDB6E-AE6D-11cf-96B8-444553540000' name='player' width='500' height='350'>      <param name='movie' value='player-viral.swf' />     <param name='allowfullscreen' value='true' />       <param name='allowscriptaccess' value='always' />       <param name='flashvars' value='file=~/User/Trailorvideos/" + videoname + "&autostart=true' />   <p><a href='http://get.adobe.com/flashplayer'&gt;Get Flash</a> to see this player.</p>         </object>";
        }
        else
        {
            dvplayer.InnerHtml = "<object type='application/x-shockwave-flash' data='player-viral.swf' width='500' height='350'> <param name='movie' value='player-viral.swf' /> <param name='allowfullscreen' value='true' /> <param name='allowscriptaccess' value='always' /> <param name='flashvars' value='file=~/User/Trailorvideos/" + videoname + "&autostart=true' /> <p><a href='http://get.adobe.com/flashplayer'&gt;Get Flash</a> to see this player.</p> </object>";
        }
        GetQuickList(videoid);
    }
    catch (Exception ex)
    {

    }
}

above code .cs code

Answer 1

Hello,

Add a command name to the button. I think that is the reason.

HTH.

Answer 2

My guess is that you are not databinding the DataList on a postback. Events are not fired if the control isn't databound. Can you post the code that does your databinding, maybe in Page_Load?

Answer 3

When are you binding the DataList? If the DataList is bound on PageLoad but you are not handling for a PostBack then all attached event handlers will be lost as the DataList is re-bound. The ItemCommand event will never be raised in this case.

Make sure your Page_Load method is structured as follows:

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack)  //this IF statement is what prevents re-binding on PostBack
   {
      //Bind DataList
   }
}

The above code will ensure that the DataList is not re-created on PostBack.

Take a look at this MSDN article that covers the Page.IsPostBack property

Answer 4

I think what dave said is correct.

Answer 5

This works:

markup:

<asp:DataList ID="DLQuickVideos" runat="server"  RepeatColumns ="2" CellPadding="0" CellSpacing="0" OnItemCommand="DLQuickVideos_ItemCommand" >                       
     <ItemTemplate>                                        
         <asp:ImageButton ID="imgbtn" runat="server" ImageUrl='xx' CommandArgument='<%# "test" + "|" + Eval("Test") %>' CausesValidation="false"  Width="111px" Height="83px" BorderStyle="double" BorderWidth="4px" BorderColor="#A70202" />                                                                    
     </ItemTemplate>
</asp:DataList>

code behind:

protected void Page_Load(object sender, EventArgs e)
        {


            {
                if (!IsPostBack)  //this IF statement is what prevents re-binding on PostBack
                {
                    System.Data.DataTable dt = new System.Data.DataTable();
                    dt.Columns.Add(new System.Data.DataColumn("test", typeof(int)));

                    System.Data.DataRow r = dt.NewRow();
                    r["test"] = 1;
                    dt.Rows.Add(r);

                    r = dt.NewRow();
                    r["test"] = 2;
                    dt.Rows.Add(r);

                    this.DLQuickVideos.DataSource = dt;
                    this.DLQuickVideos.DataBind();
                }
            }


        }

        protected void DLQuickVideos_ItemCommand(object source, DataListCommandEventArgs e)
        {

            try
            {

            }
            catch (Exception ex)
            {

            }
        }

But what i don't understand is you are calling GetQuickList in DLQuickVideos_ItemCommand. What for? But where do you initially fill the DataList?

Answer 6

You have posted that this is your page load event:

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!IsPostBack) //this IF statement is what prevents re-binding on PostBack 
    { 
        GetQuickList(videoid, moviename); 
    } 
    else 
    { 
        GetQuickList(videoid, moviename) 
    } 
}

This will not work. You must not databind on post back. Otherwise any pending event handler requests are cancelled.

You must remove the else part of this if statement.