C# using linq question

Question

I am working in a C# 2010 application where I have written the following lines of linq to sql code:

int TotCount = 0;
string[] PkgIDs = rptData.Transaction.Where(c =>c.Package_ID.StartsWith("rva") &&
                                c.Received_Date != null ).Select(c => c.Package_ID).ToArray();
            foreach (string PkgID in PkgIDs)
            {
                var eCnt = rptData.Details.Where(c =>c.Package_ID == PkgID).Select(c =>c.TotalTrans);
                TotCount = Convert.ToInt32(eCnt);
            }

My problem line of code is:    var eCnt = rptData.Details.Where(c =>c.Package_ID == PkgID).Select(c =>c.TotalTrans);

I want to be able to obtain the value contained in the c.TotalTrans field and place the value in the eCnt field.

When I am stepping through the code and go to the line right after the line I listed above, I only see the sql equivalent value. I want to see the value for c.TotalTrans in the eCnt field.

I know what I need now is to actually make the linq to sql statement actually execute. That would be similar to the 'ToArray()'
statement listed above. However, I do not know what to change in the statement to actually obtain the value.

Thus can you tell me what else I need to add to this statement so that I get my desired result?

Vulpes · Answer

Are you sure you've added the parentheses after FirstOrDefault? They need to be there as it's a method rather than a property.

Chiranjita Nayak · Answer

Try Like this way var eCnt = rptData.Details.Single(c =>c.Package_ID == PkgID).TotalTrans;

Sie Ste · Answer

When I try what you say, I get the following error message "Error 1 Cannot assign method group to an implicitly-typed local variable ". Thus can you tell me what else to try with this statement and/or how to rewrite the linq to sql statement to get the results I am looking for?

Vulpes · Answer

If you're just expecting to get (at most) a single value from that query, I'd use either the FirstOrDefault or the SingleOrDefault extension method. The difference is that the latter throws an exception if there's more than one value in the sequence: var eCnt = rptData.Details.Where(c =>c.Package_ID == PkgID).Select(c=>c.TotalTrans).FirstOrDefault();

C# using linq question

Answers (4)