This is killing me, I've been trying to figure this out for 2 days.
When I click on the linkbutton, it executes the GetData(int) method to set
the DataSource. The FAILURE is when it tries to call databind
(sender.DataBin d();
in NeedList_ItemCo mmand method). The error message is at the bottom of this
message (System.NullRef erenceException )
Can anyone else see anything wrong with this? (I've included all relevant
code, stored procedure and table)
This datalist is within a selecteditemtem plate...FYI....
---------------------------ASP.NET Code----------------------------
<asp:datalist id="TechList" runat="server" DataSource='<%#
GetData((int)Da taBinder.Eval(C ontainer.DataIt em, "NeedID")) %>'
RepeatDirection ="Vertical" repeatcolumns=" 1" Width="100%" CellPadding="0"
cellspacing="0" OnItemCommand=" NeedList_ItemCo mmand">
<headertemplate >
</headertemplate>
<itemtemplate >
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td width="100">
<asp:linkbutt on id="Linkbutton3 " runat="server" Text='<%#
DataBinder.Eval (Container.Data Item, "NeedID") %>'/>
</td>
</tr>
</table>
</itemtemplate>
</asp:datalist>
---------------------------Source Code----------------------------
protected void NeedList_ItemCo mmand(object Sender, DataListCommand EventArgs
e)
{
// change the selected index of Datalist
string cmd = ((LinkButton)e. CommandSource). CommandName;
DataList sender = (DataList)Sende r;
if (cmd == "select")
sender.Selected Index = e.Item.ItemInde x;
// re-bind to display info with new selected index.
//sender.DataSour ce = GetEnablingTech s((int)ViewStat e[_needID]);
sender.DataSour ce = GetData((int)Vi ewState[_needID]);
//******This is where it is failing******** **
sender.DataBind ();
}
protected DrillDownReport Collection GetData(int needID)
{
// only use the needID in session if it doesn't exist.
if (needID == 0)
needID = (int)ViewState[_needID];
return DrillDownReport .GetData(needID );
}
public static DrillDownReport Collection GetData(int needID)
{
DataSet dsData = SqlHelper.Execu teDataset(
ConfigurationSe ttings.AppSetti ngs[Global.CfgKeyCo nnString],
"WN_GetAllNeeds ");
DrillDownReport Collection items = new DrillDownReport Collection();
foreach(DataRow row in dsData.Tables[0].Rows)
{
DrillDownReport item = new DrillDownReport ();
item.EnableTech ID = Convert.ToInt32 (row["NeedID"].ToString());
item.EnableTech Name = row["NeedName"].ToString();
items.Add(item) ;
}
return items;
}
---------------------------Stored Procedure----------------------------
CREATE PROCEDURE WN_GetAllNeeds
AS
SELECT * FROM WN_Needs
GO
---------------------------Table----------------------------
CREATE TABLE [WN_Needs] (
[NeedID] [int] NOT NULL ,
[NeedName] [char] (50) COLLATE SQL_Latin1_Gene ral_CP1_CI_AS NULL
)
) ON [PRIMARY]
GO
---------------------------Error Message----------------------------
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.
Exception Details: System.NullRefe renceException: Object reference not set
to an instance of an object.
Source Error:
Line 56: </td>
Line 57: <td>
Line 58: <asp:datalist id="TechList" runat="server"
DataSource='<%# GetData((int)Da taBinder.Eval(C ontainer.DataIt em, "NeedID"))
%>' RepeatDirection ="Vertical" repeatcolumns=" 1" Width="100%" CellPadding="0"
cellspacing="0" OnItemCommand=" NeedList_ItemCo mmand">
Line 59: <headertemplate >
Line 60:
Source File: c:\inetpub\wwwr oot\TamTest\Dri llDown.aspx Line: 58
Stack Trace:
[NullReferenceEx ception: Object reference not set to an instance of an
object.]
ASP.DrillDown_a spx.__DataBind_ _control8(Objec t sender, EventArgs e) in
c:\inetpub\wwwr oot\TamTest\Dri llDown.aspx:58
System.Web.UI.C ontrol.OnDataBi nding(EventArgs e) +66
System.Web.UI.W ebControls.Base DataList.OnData Binding(EventAr gs e) +9
System.Web.UI.W ebControls.Base DataList.DataBi nd() +23
ASPNET.StarterK it.Reports.Dril lDown.NeedList_ ItemCommand(Obj ect Sender,
DataListCommand EventArgs e) in c:\inetpub\wwwr oot\tamtest\dri lldown.aspx.cs: 89
System.Web.UI.W ebControls.Data List.OnItemComm and(DataListCom mandEventArgs
e) +110
System.Web.UI.W ebControls.Data List.OnBubbleEv ent(Object source, EventArgs
e) +60
System.Web.UI.C ontrol.RaiseBub bleEvent(Object source, EventArgs args) +26
System.Web.UI.W ebControls.Data ListItem.OnBubb leEvent(Object source,
EventArgs e) +100
System.Web.UI.C ontrol.RaiseBub bleEvent(Object source, EventArgs args) +26
System.Web.UI.W ebControls.Link Button.OnComman d(CommandEventA rgs e) +121
System.Web.UI.W ebControls.Link Button.System.W eb.UI.IPostBack EventHandler.Ra isePostBackEven t(String eventArgument) +115
System.Web.UI.P age.RaisePostBa ckEvent(IPostBa ckEventHandler
sourceControl, String eventArgument) +18
System.Web.UI.P age.RaisePostBa ckEvent(NameVal ueCollection postData) +138
System.Web.UI.P age.ProcessRequ estMain() +1292
