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How to I do a ToString inside LINQ

The goal of this code is to write out XML. The first section of code gathers the data. The second attempts to write out the XML. The code fails on converting a GUID to a string.

When the second section, the foreach, execute it throws this error:

“Unable to cast object of type 'System.Guid' to type 'System.String'”

var outboxMessages = (from x in outbox
                                  //var outboxString = from x in outbox
                                  join m in messageContext on x.MessageId equals m.MessageId
                                  join p in messageProperty on m.MessageId equals p.MessageId
                                  join a in messageArchive on p.MessageId equals a.MessageId
                                  where p.PropertyName == "DocumentNumber"
                                  select new {id = x.MessageId , m.MessageType, a.CreatedOn, x.QueuedOn, p.Value, 
                                      m.ReceivePortId, m.InboundTransportType}).ToList();

foreach (var i in outboxMessages)
            {
                outboxXML.Add(new XElement("Message", new XAttribute("Id", i.id), new XAttribute("Type", i.MessageType),
                    new XAttribute("CreatedOn", i.CreatedOn), new XAttribute("ProcessedOn", i.QueuedOn),
                    new XAttribute("DocumentNumber", i.Value), new XAttribute("ReceivePortId", i.ReceivePortId),
                    new XAttribute("InboundTransportType", i.InboundTransportType)));
            }

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Gururaj Badam

Where's the GUID in your code?

Did you try "as string" ?

Bruce

ASKER

Sorry

Here it is...
Attribute id

outboxXML.Add(new XElement("Message", new XAttribute("Id", i.id),

Gururaj Badam

did you try this

outboxXML.Add(new XElement("Message", new XAttribute("Id", i.id) as string,

Bruce

ASKER

The code doesn’t even get that far. The error is actually produced when the query executes. However, it isn’t thrown until the foreach loop is initialized.

SOLUTION

Gururaj Badam

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Bruce

ASKER

I changed the linq to not even select the x.MessageId anymore, and it still throws that error.

Gururaj Badam

I'm not sure where it's going wrong. Paste the stack trace.

Bruce

ASKER

at System.Data.SqlClient.SqlBuffer.get_String()
at System.Data.SqlClient.SqlDataReader.GetString(Int32 i)
at Read_<>f__AnonymousType5`6(ObjectMaterializer`1 )
at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
at MessageSink.MessageStatus.GetOutboxMessages(DataContext db) in N:\MessageSink\MessageStatus.cs:line 154
at MessageSink.MessageStatus.LogMessageStatus() in N:\MessageSink\MessageStatus.cs:line 50
at MessageSink.MainForm.SaveMessageStatus() in N:\MessageSink\MainForm.cs:line 199

Gururaj Badam

This may help you

http://stackoverflow.com/questions/318716/asp-net-mvc-iis6-error-on-high-traffic-specified-cast-is-not-valid

Fernando Soto

Can you post the query as you changed it and on what line of the code do you get the error on and the error message please.

Bruce

ASKER

The outboxMessages object contains the error as soon as the line of code is executed.

var outboxMessages = (from x in outbox
                                  //var outboxString = from x in outbox
                                  join m in messageContext on x.MessageId equals m.MessageId
                                  join p in messageProperty on m.MessageId equals p.MessageId
                                  join a in messageArchive on p.MessageId equals a.MessageId
                                  where p.PropertyName == "DocumentNumber"
                                  select new {id = x.MessageId , m.MessageType, a.CreatedOn, x.QueuedOn, p.Value, 
                                      m.ReceivePortId, m.InboundTransportType}).ToList();

The outboxMessages object contains the error as soon as the line of code is executed.

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ASKER CERTIFIED SOLUTION

Fernando Soto

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Gururaj Badam

how many of your columns in the DB Table have Identity Columns and which one's you're using the in LINQ Expr.