Passing parameter to delegate function

Question

I currently have this:

instance = new Class1<Type1>(
                 "param1",
                 () =>
                 new ViewDataDictionary<Type2>(
                     new Class2
                    {
                        Prop1= CreateList(new List<long> { 234 }),
                         Prop2= CreateList(new long[] { 234 })
                     }) );

I want to pass a variable in the function CreateList instead. Something like this

long p1 = 123;
instance = new Class1<Type1>(
                     "param1",
                     () =>
                     new ViewDataDictionary<Type2>(
                         new Class2
                        {
                            Prop1= CreateList(new List<long> { p1}),
                             Prop2= CreateList(new long[] { p1})
                         }) );

But it gives me serialization error if I try to do the above. All the classes are marked serializable.

Answer 1

When you reference a local variable in a lambda expression, it generates a closure (a compiler-generated class that "captures" your local variable as a field). This closure is not marked as serializable, so the serialization fails...

Instead, you could change the type of the lambda expression to accept a parameter, and pass the value as a separate parameter :

long p1 = 123;
instance = new Class1<Type1>(
                 "param1",
                 (prm) =>
                 new ViewDataDictionary<Type2>(
                     new Class2
                    {
                        Prop1= CreateList(new List<long> { prm }),
                         Prop2= CreateList(new long[] { prm })
                    }),
                 p1);