C#调用Dephi的DLL疑问

C#调用Dephi的DLL疑问，在线等
function GetVcell_Index(Devicechannum,IndexSs:Integer;var mV:widestring):Integer;stdcall;
  传递参数：Devicechannum: 通道号 (只有一个通道，这里可以传1)
  IndexSs:第几串
  mV:(回传值）  
  返回参数：=0 表明不成功
  =1 表明成功

这是他的调用函数，那么我C#调用该如何调用，因为这个包含了2个返回值，就蒙了。。
C#大致应该如下吧？
  [DllImport("UserDll.dll", CallingConvention = CallingConvention.StdCall)]
  // public static extern int GetVcell_Index(string OrignStr, string Key, int NewStr);
以上仅供参考，能力有限，还请大虾帮忙!

[解决办法]
public static extern int GetVcell_Index(int Devicechannum,int IndexSs,ref string mV);
试试
[解决办法]
话说一种语言去调用一种语言是很苦难的事情
所以才有COM COM+ 到现在.NET

可以试试楼上的
[解决办法]
public static extern int GetVcell_Index(int Devicechannum,int IndexSs,ref string mV);

string mV = "";
int Val = 0;
Val = GetVcell_Index(1,1,ref mV);

Val是返回值
[解决办法]

C# code

public delegate int FARPROC();[System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]public struct HINSTANCE__ {        /// int    public int unused;}public partial class NativeMethods {        /// Return Type: HMODULE->HINSTANCE->HINSTANCE__*    ///lpFileName: LPCTSTR->LPCWSTR->WCHAR*    [System.Runtime.InteropServices.DllImportAttribute("kernel32.dll", EntryPoint="LoadLibraryW")]public static extern  System.IntPtr LoadLibraryW([System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPTStr)] string lpFileName) ;        /// Return Type: FARPROC    ///hModule: HMODULE->HINSTANCE->HINSTANCE__*    ///lpProcName: LPCSTR->CHAR*    [System.Runtime.InteropServices.DllImportAttribute("kernel32.dll", EntryPoint="GetProcAddress")]public static extern  FARPROC GetProcAddress([System.Runtime.InteropServices.InAttribute()] System.IntPtr hModule, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string lpProcName) ;}