Functions & Property Usage in Object Initializers

Question

Does the spec of C# prevent calling a method from within an object's (or struct's) initializer construct?

The reason I'm asking is because I was trying to use a LINQ-to-XML statement to use gater data within the initializer. This does not work. However, if I get the data before hand saved into a local variable it works without issue. I just was wondering why this happens, since I have already figured out the error in my code.

Does Not Work:

SavedData sData = new SavedData()
{
        exportLocation = data.Root.Descendants("ExportLocation").FirstOrDefault().Value,
        exportType = (ExportType)data.Root.Descendants("ExportType").FirstOrDefault().Value
};

Works:

var exLoc = data.Root.Descendants("ExportLocation").FirstOrDefault().Value;
ExportType type = (ExportType)data.Root.Descendants("ExportType").FirstOrDefault().Value;

Saved Data sData = new SavedData()
{
     exportLocation = exLoc,
     exportType = type
};

What do you mean by *does not work*? It compiles just fine to me. — MarcinJuraszek, Jan 06 '14 at 22:15
It should work. We could maybe help if you told us how it doesn't work exactly. — fejesjoco, Jan 06 '14 at 22:17
@MarcinJuraszek _does not work_ in this case does not mean it does not compile. The object does not initialize and equates to null. — JNYRanger, Jan 07 '14 at 14:36

score 1 · Accepted Answer · answered Jan 06 '14 at 22:31

You can call methods within initializers, so there is something else going on here.

The following works fine for me:

    class A
    {
        public int x { get; set; }
    }

    class B
    {
        public int foo()
        {
            return 3;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            B data = new B();
            A a = new A() {
                x = data.foo()
            };
        }
    }

a.x gets set to 3, so it works fine.

It might be another problem with your code that was fixed when you rewrote it. It could also be something that the SavedData constructor is doing that is invalidating the data.

You were correct. It turns out that my XML file had an issue and due to that it was not parsing the `ExportType` enum value properly without being wrapped as `Enum.Parse(typeof(ExportType),[LINQ-TO-XML HERE])` Thanks for pointing me in the right direction. — JNYRanger, Jan 08 '14 at 16:10

Functions & Property Usage in Object Initializers

1 Answers1