从C#.Net 2010开始推出VB6功能

Question

我想PInvoke从C#用VB6编写的函数.我们可以在VB6中调用这个函数,如下所示:

Declare Function ApplyNNet Lib " location of the DLL file" (MyNNetType As String, MyAddress As String, MyInput() As Double) As Variant

我在C#中的代码是:

[DllImport("NNetApply.dll", EntryPoint = "ApplyNNet", CallingConvention = CallingConvention.StdCall)] 
public static extern IntPtr ApplyNNet(string type, string add, double[,] data);
//run ANN with data
string address = @"C:\Users\PNGE-User\Desktop\Faegheh\Project\Neural Network For Pressure Vs q,x,y\P ve x,y,q\P ve x,y,q";
        double[,] P = new double[no_data,2];
        var P_ = ApplyNNet("Back Prop", address, data);

当我调试我的代码时,出现错误:

尝试读取或写入受保护的内存.这通常表明其他内存已损坏.

Answer 1

首先,我假设DLL实际上并不是用VB6编写的.您显示Declare用于调用该函数的代码的事实与此相矛盾.所以我假设DLL是用其他语言编写的(例如C++),并且您当前正在从VB6调用DLL.

调用DLL的VB6代码声明如下:

Declare Function ApplyNNet Lib "DLLFileName" (MyNNetType As String,
    MyAddress As String, MyInput() As Double) As Variant

您的C#版本如下所示:

[DllImport("NNetApply.dll", EntryPoint = "ApplyNNet", 
    CallingConvention = CallingConvention.StdCall)] 
public static extern IntPtr ApplyNNet(string type, string add, double[,] data);

有两个明显的区别:

1. 第三个参数不匹配.而不是double[,]你需要double[].
2. 返回值不匹配.VB6变体无法与之匹配IntPtr.您需要object在C#代码中声明返回值是类型.

所以pinvoke应该是:

[DllImport("NNetApply.dll")] 
public static extern object ApplyNNet(string type, string add, double[] data);

更新

使用此声明,您会收到pinvoke错误:

PInvoke限制:无法返回变体.

我不知道你怎么能在pinvoke中解决这个问题.在你的情况下,我想我会创建一个包装DLL并将其作为COM接口公开的VB6项目.然后,我将为您的C#项目添加一个COM引用,然后继续.