Linq Query returning GUID

[scott1010]

Hello I am having problems with a Linq query. I need to return an ID field which is of type GUID (c.Id) along with other fields of type String.

I have tried both anonymous types and strongly typed objects but continue to encounter the same error:

Method 1: Anonymously Typed

var results = (from c in uow.Contacts orderby c.LastName ascending, c.FirstName ascending select new {ID=c.Id, Title = c.Title, LastName=c.LastName, FirstName=c.FirstName, Email=c.ContactEmailAddresses[0].Email }).Take(2);
 
foreach (ContactResult r in results)    <<<< Error occurs here
{
...
}
 

Method 2: Strongly Typed to custom class ContactResult

public class ContactResult
{
        public Guid ID;
        public String Title;
        public String LastName;
        public String FirstName;
        public String Email;
 }
 

var results = (from c in uow.Contacts orderby c.LastName ascending, c.FirstName ascending select new ContactResult(){ID=c.Id, Title = c.Title, LastName=c.LastName, FirstName=c.FirstName, Email=c.ContactEmailAddresses[0].Email }).Take(2);
 
foreach (ContactResult r in results)    <<<< Error occurs here
{
...
}
 

Both methods encounter this error - which results due to the GUID

[InvalidCastException: Invalid cast from 'System.String' to 'System.Guid'.]
   System.Convert.DefaultToType(IConvertible value, Type targetType, IFormatProvider provider) +7569852
   System.String.System.IConvertible.ToType(Type type, IFormatProvider provider) +8
   System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider) +7601872
   Mindscape.LightSpeed.Linq.Utils.TypeHelper.NullableSafeConvert(Object value, Type targetType) +245
   Mindscape.LightSpeed.Linq.ProjectedTypeBuilder.GetValue(Int32 expressionIndex, IDataRecord record, Type targetType) +173
   Mindscape.LightSpeed.Linq.NamedTypeBuilder.InitialiseMembersFromReader(MemberInitExpression memberInit, IDataRecord record, Object instance) +476
   Mindscape.LightSpeed.Linq.NamedTypeBuilder.Build(IDataRecord record) +103
   Mindscape.LightSpeed.Linq.Plan.SingleQueryPlan.ProjectNative(IUnitOfWork unitOfWork) +223
   Mindscape.LightSpeed.Linq.Plan.SingleQueryPlan.ExecuteImmediate(IUnitOfWork unitOfWork, Type returnType) +1580
   Mindscape.LightSpeed.Linq.LinqQueryProvider.Execute(Expression expression) +237
   Mindscape.LightSpeed.Linq.LinqQueryProvider.System.Linq.IQueryProvider.Execute(Expression expression) +37
   Mindscape.LightSpeed.Linq.LinqQuery`1.GetEnumerator() +40
 

Any help would be greatly appreciated in trying to eliminate this error, I need to be able to get the GUID.

Thanks,
Scott

[Christian Binder]

I think a error clearly states what's happening ...

[InvalidCastException: Invalid cast from 'System.String' to 'System.Guid'.]

So c.Id is probably a String, not a Guid!
But you can make a Guid out of a String with

Guid g = new Guid(guidStirng);

Applied to your example:

var results = (from c in uow.Contacts 
               orderby c.LastName ascending, c.FirstName ascending 
               select new ContactResult(){ID=new Guid(c.Id), Title = c.Title, LastName=c.LastName, FirstName=c.FirstName, Email=c.ContactEmailAddresses[0].Email }
              ).Take(2);

[scott1010]

No its definitely a GUID.

I had a further thought after I posted and it turns out it was bug in database tool I was using, and they are releasing a fix.

Thanks
Scott