Can struct objects be allocated to managed stacks?

Can struct objects be allocated to managed stacks?

 

Can struct objects be allocated to managed stacks?

-- Yes.

 

For example, when struct is packed, it is allocated to the managed stack.

 

For example, let a struct implement an interface.

 

    public interface IReport
    {
        string Name { get; }
    }
    public struct Score : IReport
    {
        public string Name
        {
Get {return "80 points from struct ";}
        }
    }

 

Another class is used to print the class and method of the interface property value.

 

   public class Tester
    {
        public void Test(IReport report)
        {
            Console.WriteLine(report.Name);
        }
    }

 

Then the Main method is called as follows:

 

        static void Main(string[] args)
        {
            var tester = new Tester();
            tester.Test(new Score());
            Console.ReadKey();
        }

 

Now, we want to check whether struct has been packed.

 

Open "VS2012 developer command prompt ".

 

Navigate to the EXE folder and use ildasmto decompile the ilcode to output it to a 1.txt file.

 

 

We can see that the struct object is packed.

 

 

So how can we avoid packing?

 

You can add a generic method to the Tester class.

 

   public class Tester
    {
        public void Test(IReport report)
        {
            Console.WriteLine(report.Name);
        }
        public void TestGeneric<T>(T report) where T : IReport
        {
            Console.WriteLine(report.Name);
        }
    }

 

Then use the generic method in the Main method.

 

        static void Main(string[] args)
        {
            var tester = new Tester();
            tester.TestGeneric(new Score());
            Console.ReadKey();
        }

 

Run again, decompile again, and view the IL code:

 

 

We found that struct is no longer packed.

 

Why?

 

The type of method parameters is limited in generic methods, and struct meets the type requirements. When a struct object is passed in as a real parameter, the generic method directly uses struct instead of IReport, thus avoiding struct packing.