"A lambda expression with a statement body cannot be converted to an expression tree"

c# linq entity-framework linq-to-entities
pistacchio picture pistacchio · Mar 3, 2011 · Viewed 110.2k times · Source

In using the EntityFramework, I get the error "A lambda expression with a statement body cannot be converted to an expression tree" when trying to compile the following code:

Obj[] myArray = objects.Select(o =>
{
    var someLocalVar = o.someVar;

    return new Obj() { 
    Var1 = someLocalVar,
    Var2 = o.var2 };
}).ToArray();

I don't know what the error means and most of all how to fix it. Any help?

Answer

Tim Rogers picture Tim Rogers · Mar 3, 2011

Is objects a Linq-To-SQL database context? In which case, you can only use simple expressions to the right of the => operator. The reason is, these expressions are not executed, but are converted to SQL to be executed against the database. Try this

Arr[] myArray = objects.Select(o => new Obj() { 
    Var1 = o.someVar,
    Var2 = o.var2 
}).ToArray();

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