C#程序調用C#dll

Question

我想用C#的exe動態加載C#或者C++構建的dll，C++的dll部分已經完成了，但是C#的dll還沒有完成，因為exe在C#的dll中找不到方法。

這是我的 C# dll 代碼，它將構建一個 CSharp.dll：

namespace NamespaceName
{
    public class ClassName
    {
        static public double MethodName(string input)
        {
            Console.WriteLine(input);
            Console.Read();
            return 0;
        }
    }
}

這是我的 C# exe 代碼：

using System;
using System.Runtime.InteropServices;

namespace TestCall
{
    class Program
    {
        [DllImport("kernel32.dll", EntryPoint = "LoadLibrary")]
        static extern int LoadLibrary([MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);
        [DllImport("kernel32.dll", EntryPoint = "GetProcAddress")]
        static extern IntPtr GetProcAddress(int hModule, [MarshalAs(UnmanagedType.LPStr)] string lpProcName);
        [DllImport("kernel32.dll", EntryPoint = "FreeLibrary")]
        static extern bool FreeLibrary(int hModule);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate double MethodName(string a);

        static void Main(string[] arg)  //pass in string array
        {
            string DllName = "...Desktop//CSharp.dll";                 //would be like: string  DllName = ChooseWhatDllToCall();
            string FuncName = "NamespaceName@ClassName@MethodName";    //would be like: string FuncName = ChooseWhatFuncToUse();
            int hModule = LoadLibrary(DllName);
            if (hModule == 0)
                return;
            IntPtr intPtr;
            intPtr = GetProcAddress(hModule, FuncName);
            if ((int)intPtr == 0)
            {
                FreeLibrary(hModule);
                return;
            }
            MethodName run = (MethodName)Marshal.GetDelegateForFunctionPointer(intPtr, typeof(MethodName));
            string input = "just a string that will print by dll method";
            double result = run(input);
            FreeLibrary(hModule);
            return;
        }
    }
}

如果我正在加載 Cpp.dll， if ((int)intPtr == 0)將為假，加載 CSharp.dll 將為真，所以我猜我需要編輯string FuncName = "NamespaceName@ClassName@MethodName"; 到別的東西。 我怎樣才能解決這個問題？

Answer 1

我現在回答我自己的問題，它可能不完美，但它有效，感謝您的評論建議。

using System;
using System.Runtime.InteropServices;
using System.Reflection;

namespace TestCall   
{
    class Program
    {
        [DllImport("kernel32.dll", EntryPoint = "LoadLibrary")]
        static extern int LoadLibrary([MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);
        [DllImport("kernel32.dll", EntryPoint = "GetProcAddress")]
        static extern IntPtr GetProcAddress(int hModule, [MarshalAs(UnmanagedType.LPStr)] string lpProcName);
        [DllImport("kernel32.dll", EntryPoint = "FreeLibrary")]
        static extern bool FreeLibrary(int hModule);
        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate double MyMethod(string a);

        static void Main(string[] arg) 
        {

            string DllName = "...Desktop\\CSharp.dll";  //or Cpp.dll
            string FuncName = "MyMethod";


            string input = "Just A String";


            int hModule = LoadLibrary(DllName); // you can build it dynamically 
            IntPtr intPtr = GetProcAddress(hModule, FuncName);
            if ((int)intPtr!=0 && hModule != 0)  //can I try this way?
            {                                    //                      Yes!
                MyMethod run = (MyMethod)Marshal.GetDelegateForFunctionPointer(intPtr, typeof(MyMethod));
                double result = run(input);
                Console.WriteLine(result);
                Console.Read();
                FreeLibrary(hModule);
                return;
            }
            else                                 //No! 
            {
                FreeLibrary(hModule);

                                                 //so I try other way
                var DLL = Assembly.LoadFile(DllName);
                foreach (Type type in DLL.GetExportedTypes())
                {
                    var c = Activator.CreateInstance(type);
                    type.InvokeMember(FuncName, BindingFlags.InvokeMethod, null, c, new object[] { input });
                }
                return;
            }
        }
    }
}