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if LINQ statement has no results?

Posted on 2011-03-03
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Last Modified: 2012-08-14
hi all, below is my linq statment

the ID of is 10000 which the table its being asked to get data from doesnt have an ID for this record yet

so at the moment i get the below error

but i want to obviously still load the page if this table doesnt yet have an ID for the record (it will be added when they fill something in)

can someone show me hwo to do it?
Thanks
##################### ERROR #########################
Server Error in '/' Application.

Sequence contains no elements

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 no elements

Source Error: 


Line 33:         using (CompanyDataContext dc = new CompanyDataContext())
Line 34:         {
Line 35:             var CompQuery = (from C in dc.CompanyInsurances
Line 36:                              where C.ID == Convert.ToInt16(StrID)
Line 37:                              select C).Single();

Source File: e:\netfolder\companies\insurance.aspx.cs    Line: 35 

Stack Trace: 


[InvalidOperationException: Sequence contains no elements]
   System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) +4539
   System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) +207
   System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +500
   System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute(Expression expression) +50
   System.Linq.Queryable.Single(IQueryable`1 source) +383
   Insurance.Page_Load(Object sender, EventArgs e) in e:\netfolder\companies\insurance.aspx.cs:35
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +25
   System.Web.UI.Control.LoadRecursive() +71
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3048

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using (CompanyDataContext dc = new CompanyDataContext())
        {
            var CompQuery = (from C in dc.CompanyInsurances
                             where C.ID == Convert.ToInt16(StrID)
                             select C).Single();

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Question by:awilderbeast
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5 Comments
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 2000 total points
ID: 35028608
Try SingleOrDefault() rather than Single().
0
 
LVL 1

Author Comment

by:awilderbeast
ID: 35028655
that did the trick but then my next lines...

can i wrap all them in some if statement that will do nothing if there is no entry?

Thanks
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 


Line 37:                              select C).SingleOrDefault();
Line 38: 
Line 39:             PLLimit.Text = CompQuery.PLLimit;

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0
 
LVL 75

Assisted Solution

by:käµfm³d 👽
käµfm³d   👽 earned 2000 total points
ID: 35028842

if (CompQuery != null)
{
   // do work
}

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0
 
LVL 1

Author Closing Comment

by:awilderbeast
ID: 35028863
thanks alot!
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 35028874
NP. Glad to help  : )
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