Compiler Error CS1529

A using clause must precede all other elements defined in the namespace except extern alias declarations

A using clause must appear first in a namespace.

Example

The following sample generates CS1529:

// CS1529.cs  
namespace X  
{  
    namespace Subspace  
    {  
        using Microsoft;  
  
        class SomeClass  
        {  
        };  
  
        using Microsoft;      // CS1529, place before class definition  
    }  
  
    using System.Reflection;  // CS1529, place before namespace 'Subspace'  
}  
  
using System;                 // CS1529, place at the beginning of the file