C# System.EntryPointNotFoundException:找不到入口点

我已经将VB6转换为c#并在执行时生成此错误

来自VB6

Declare Function OpenCommPort Lib "C:\Program Files\MR705API.dll" Alias "?OpenCommPort@@YGHPADPAPAX@Z" (ByVal PortName As String, ByRef hCom As Long) As Long
Declare Function CloseCommPort Lib "C:\Program Files\MR705API.dll" Alias "?CloseCommPort@@YGHPAX@Z" (ByVal hCom As Long) As Long
Declare Function SetLED Lib "C:\Program Files\MR705API.dll" Alias "?SetLED@@YGHPAXEE@Z" (ByVal hCom As Long, ByVal Led As Byte, ByVal Addr As Byte) As Long
Declare Function ActiveBuzzer Lib "C:\Program Files\MR705API.dll" Alias "?ActiveBuzzer@@YGHPAXEE@Z" (ByVal hCom As Long, ByVal DelayTime As Byte, ByVal Addr As Byte) As Long
Declare Function Iso14443Reqa Lib "C:\Program Files\MR705API.dll" Alias "?Iso14443Reqa@@YGHPAXEPAEE@Z" (ByVal hCom As Long, ByVal ReqAMode As Byte, ByVal ATQ As String, ByVal Addr As Byte) As Long
Declare Function Iso14443Anticoll Lib "C:\Program Files\MR705API.dll" Alias "?Iso14443Anticoll@@YGHPAXEPAE1E@Z" (ByVal hCom As Long, ByVal AnticollMode As Byte, ByVal Uid As String, ByVal MultiTag As String, ByVal Addr As Byte) As Long

用C#

以及我如何使用它。

public void doReader() {

            Result = OpenCommPort("COM9", ref HANDLE);
            ....
            ....
}

例外情况

System.EntryPointNotFoundException: Unable to find an entry point named 'OpenCommPort' in DLL 'MR705API.dll'.

   at TrueReader.MainForm.OpenCommPort(String portName, Int64& hCom)
   at TrueReader.MainForm.doReader() in c:\Users\sattha\Documents\SharpDevelop Projects\TrueReader\TrueReader\MainForm.cs:line 59
   at TrueReader.MainForm.Timer1Tick(Object sender, EventArgs e) in c:\Users\sattha\Documents\SharpDevelop Projects\TrueReader\TrueReader\MainForm.cs:line 54
   at System.Windows.Forms.Timer.OnTick(EventArgs e)
   at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at TrueReader.Program.Main(String[] args) in c:\Users\sattha\Documents\SharpDevelop Projects\TrueReader\TrueReader\Program.cs:line 27

谁能指引我，我做错了什么？？或者我错过了什么

我不知道这个.dll是怎么写的，用哪种语言写的

但它以前在VB6中使用过

您应该为每个DLLIMPORT函数定义入口点

只需将入口点从

Alias

从VB6代码复制到C#

例如。。。VB6中的“OpenCommPort”

Declare Function OpenCommPort Lib "C:\Program Files\MR705API.dll" Alias "?OpenCommPort@@YGHPADPAPAX@Z" (ByVal PortName As String, ByRef hCom As Long) As Long
Declare Function CloseCommPort Lib "C:\Program Files\MR705API.dll" Alias "?CloseCommPort@@YGHPAX@Z" (ByVal hCom As Long) As Long
Declare Function SetLED Lib "C:\Program Files\MR705API.dll" Alias "?SetLED@@YGHPAXEE@Z" (ByVal hCom As Long, ByVal Led As Byte, ByVal Addr As Byte) As Long
Declare Function ActiveBuzzer Lib "C:\Program Files\MR705API.dll" Alias "?ActiveBuzzer@@YGHPAXEE@Z" (ByVal hCom As Long, ByVal DelayTime As Byte, ByVal Addr As Byte) As Long
Declare Function Iso14443Reqa Lib "C:\Program Files\MR705API.dll" Alias "?Iso14443Reqa@@YGHPAXEPAEE@Z" (ByVal hCom As Long, ByVal ReqAMode As Byte, ByVal ATQ As String, ByVal Addr As Byte) As Long
Declare Function Iso14443Anticoll Lib "C:\Program Files\MR705API.dll" Alias "?Iso14443Anticoll@@YGHPAXEPAE1E@Z" (ByVal hCom As Long, ByVal AnticollMode As Byte, ByVal Uid As String, ByVal MultiTag As String, ByVal Addr As Byte) As Long

别名“？OpenCommPort”@@YGHPADPAPAX@Z"

到->C#中的“OpenCommPort”

附加的

---

long

inVB6相当于

int

inC#

在VB6中的long相当于.NET中的In32，因此您的pinvoke是错误的。如果它找不到与错误信号匹配的信号，则该错误将被忽略result@Plutonix你的意思是我必须从long更改为int32？@PUROTIX它无论如何都不起作用是的，这就是我所指的。@JongzPuangput“system.accessviolationexception试图读取或写入受保护内存”-通常表示p-invoke declarion不正确。e、 g.不正确的

int

长度；缺少

输出

参数

；指针；等等

[DllImport ("MR705API.dll",
EntryPoint="?OpenCommPort@@YGHPADPAPAX@Z")]
public static extern int OpenCommPort(string portName, ref int hCom);