CODEWITHSUNDEEP
c#asp.net.net
Aaron Bono
Aaron Bono

Reputation: 117

Try / Catch Exception on ASPX During Page_Load or DataBind

I am currently trying to help a client limp along with a very old .NET application written with C# and aspx. .NET and C# are not my primary, 2nd or even 3rd technologies I typically work with so my knowledge of them is rather limited.

The big problem is that we do not have the source code for the C# side of the application and the only thing we can look at or even edit is the aspx files.

We have a page that is giving us the following error:

Sequence contains more than one matching element

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.InvalidOperationException: Sequence contains more than one matching element

Source Error: 

Line 54:                            <asp:DataList ID="dlChoice" runat="server" DataSource='<%# GetChoices(Convert.ToInt32(Eval("QuestionId"))) %>' RepeatColumns="3" RepeatDirection="Horizontal" RepeatLayout="Table" EnableViewState="false">
Line 55:                                <ItemTemplate>
Line 56:                                    <span id='s<%# Eval("ChoiceId") %>' class='<%# GetChoiceStyle(Convert.ToInt32(Eval("ChoiceId"))) %>'><%# GetTextBoxes(Convert.ToInt32(Eval("QuestionId")), Convert.ToInt32(Eval("ChoiceId")),Convert.ToString(Eval("Points"))) %> <%# ReplaceToken(Eval("ChoiceText").ToString()) %></span>
Line 57:                                </ItemTemplate>
Line 58:                            </asp:DataList>

Source File: e:\inetpub\webapp\ScoringSheet.aspx Line: 56

Stack Trace: 

[InvalidOperationException: Sequence contains more than one matching element]
   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source, Func`2 predicate) +1304639
   lambda_method(ExecutionScope ) +97
   System.Linq.EnumerableExecutor`1.Execute() +244
   System.Linq.EnumerableQuery`1.System.Linq.IQueryProvider.Execute(Expression expression) +154
   System.Linq.Queryable.SingleOrDefault(IQueryable`1 source, Expression`1 predicate) +422
   CPAT.ScoringSheet.GetChoiceStyle(Int32 choiceId) +298
   ASP.scoringsheet_aspx.__DataBind__control11(Object sender, EventArgs e) in e:\inetpub\webapp\ScoringSheet.aspx:56
   System.Web.UI.Control.OnDataBinding(EventArgs e) +132
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +170
   System.Web.UI.Control.DataBindChildren() +11045679
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +182
   System.Web.UI.WebControls.DataList.CreateItem(Int32 itemIndex, ListItemType itemType, Boolean dataBind, Object dataItem) +175
   System.Web.UI.WebControls.DataList.CreateControlHierarchy(Boolean useDataSource) +734
   System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) +89
   System.Web.UI.Control.DataBindChildren() +11045679
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +182
   System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) +674
   System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) +68
   System.Web.UI.Control.DataBindChildren() +11045679
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +182
   System.Web.UI.WebControls.ListView.CreateItemsWithoutGroups(ListViewPagedDataSource dataSource, Boolean dataBinding, InsertItemPosition insertPosition, ArrayList keyArray) +924
   System.Web.UI.WebControls.ListView.CreateChildControls(IEnumerable dataSource, Boolean dataBinding) +838
   System.Web.UI.WebControls.ListView.PerformDataBinding(IEnumerable data) +46
   System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) +147
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +261
   System.Web.UI.WebControls.ListView.PerformSelect() +74
   CPAT.ScoringSheet.Page_Load(Object sender, EventArgs e) +3500
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +25
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +42
   System.Web.UI.Control.OnLoad(EventArgs e) +132
   System.Web.UI.Control.LoadRecursive() +66
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2428

Version Information: Microsoft .NET Framework Version:2.0.50727.5420; ASP.NET Version:2.0.50727.5420

My question: how can I add enough error handling to show a nice little error message where the offending tag is located but allow the rest of the page to render? This would allow me to see exactly what part of the data set is having problems. I suspect there is something amiss in the database (duplicate record, bad data, etc.) but I can't find or see the query that is running nor what data is breaking the page.

I tried adding various try / catch blocks but I suspect these data binds are run separately somehow and the try / catch I added are just ignored and the page still errors.

Upvotes: 0

Views: 1178

Answers (1)

TGH
TGH

Reputation: 39258

The issue seems to be happening inside the method CPAT.ScoringSheet.GetChoiceStyle(Int32 choiceId) Specifically there seems to be a SingleOrDefault call in there on the linq query that will fail if there is more than one element for the given input.

If this is not a valid condition I would check the data and fix it in the data. Otherwise you will have to change the code inside said method to allow more elements.

Upvotes: 1

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