Question

I have a C# file A which defined some public enum and public struct. Now I need to define errorCode for them. I defined an enum named SubsystemErrorCode in file B. Both A and B don’t have class inside. They are in the same namespace In one struct of file A, I try to use the SubsystemErrorCode enum but it give me error tell me :
Error 1 The type or namespace name ‘SubsystemErrorCode’ could not be found (are you missing a using directive or an assembly reference?)

If I move that SubsystemErrorCode into the same file. no error. But I really want them to be separated. How can I do this? thanks,

File A:

namespace SystemSoftware { 
    public struct StatusMessageBody { 
        public ProcessControlStatus State; 
        public StatVal LVP_OK; 
        public SubsystemErrorCode LVP_ERROR_CODE; 
    } 
} 

File B:

namespace SystemSoftware 
{ 
    //public class ErrorCode 
    //{ 
    public enum SubsystemErrorCode : byte 
    {
        NoError = 0, 
        EPCSS_CPU_ERROR = 1, 
        LVPS_ERROR 
    } 
    //} 
} 

Answer 1

Change your enum file to this

namespace SystemSoftware.Enums 
{  
    public enum SubsystemErrorCode : byte  
    { 
        NoError = 0,  
        EPCSS_CPU_ERROR = 1,  
        LVPS_ERROR  
     }    
} 

and in your File A put this up the top (under using System;)

using SystemSoftware.Enums;

or you could asl try in File A

public SystemSoftware.Enums.SubsystemErrorCode LVP_ERROR_CODE; 

instead of

public SubsystemErrorCode LVP_ERROR_CODE; 

Edit: Forgot to say, I’m assuming that both File A and File B are in the same project?
If not, you will need a reference in Project A, to Project B

Ok Edit Again.
I Created Two Files, like you say, in the same project. It works, here they are.

File1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace SystemSoftware
{
    public struct StatusMessageBody
    {
        public SubsystemErrorCode LVP_ERROR_CODE;
    }
}

File2.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace SystemSoftware
{
    //public class ErrorCode  
    //{  
    public enum SubsystemErrorCode : byte
    {
        NoError = 0,
        EPCSS_CPU_ERROR = 1,
        LVPS_ERROR
    }
    //}  
}