Comments on: Using Lambda Expressions with LINQ to SQL

By: Dan F

Dan F — Wed, 25 Feb 2009 03:28:40 +0000

Thanks for the explanation Richard. I googled the exception and you’re pretty close to the top. You made me chortle with “You’re not using lambdas right, you dummy!”

I’m a vb coder, so if there’s any people with similar disabilities, here’s a vb translation of the expression

Dim doesClientExist As Expressions.Expression(Of Func(Of User, Boolean)) = _
Function(user) _
user.ID = ID

…

CreateUser(doesClientExist, …)

By: Rickard Nilsson

Rickard Nilsson — Tue, 07 Oct 2008 18:48:04 +0000

Forgot to attach the generic data context:

private static System.Data.Linq.DataContext _context = null;
protected static System.Data.Linq.DataContext context
{
get
{
if (_context == null) _context = new DataContext(con);
return _context;
}
}

By: Rickard Nilsson

Rickard Nilsson — Tue, 07 Oct 2008 18:45:27 +0000

Thank you very much. You inspired me to write this:

public static T find(Expression compare)
{
IQueryable result = context.GetTable(typeof(T)).AsQueryable().OfType().Where(compare);
return result.First();
}

So now I can write:

BusinessCase bc = BusinessCase.find(myCase => myCase.description2 == “my desciption2″);

By: Andreas Hallberg

Andreas Hallberg — Thu, 28 Aug 2008 08:51:57 +0000

Thanks, nice explanation and it solved my problem.

By: NonGT

NonGT — Wed, 20 Feb 2008 02:50:44 +0000

Great topic! This give me the light,
thank you so much.