Compiler Error CS1917

  • Article

Members of read-only field 'name' of type 'struct name' cannot be assigned with an object initializer because it is of a value type.

Read-only fields that are value types can only be assigned in a constructor.

To correct this error

  • Change the struct to a class type.

  • Initialize the struct with a constructor.

Example

The following code generates CS1917:

// cs1917.cs
class CS1917
{
    public struct TestStruct
    {
        public int i;
    }
    public class C
    {
        public readonly TestStruct str = new TestStruct();
        public static int Main()
        {
            C c = new C { str = { i = 1 } }; // CS1917
            return 0;
        }
    }
}