我在尝试将数据编码(marshal)到 DLL 函数并返回到 C# 代码时遇到了这个奇怪的错误。我不知道我在哪里传递 null 或读取无效内存,并且这个错误是如此模糊。有什么线索吗??
代码如下:
FeeCalculation函数在DLL中导出如下:
extern "C" __declspec(dllexport) void __stdcall FeeCalculation(char *cin,
char *cout, char *flimit, char *frate,
char *fwindow, char *fincrement, char *fbird,
char *fparameter, char *fvalidation, char *fcoupon);
[StructLayout(LayoutKind.Sequential)]
public struct feeAnswer
{
public uint fee;
public uint tax1;
public uint tax2;
public uint tax3;
public uint tax4;
public uint surcharge1;
public uint surcharge2;
public uint validationFee;
public uint couponFee1;
public uint couponFee2;
public uint couponFee3;
public uint couponFee4;
public ushort dstay;
public ushort mstay;
};
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct feeRequest
{
public byte day;
public byte month;
public uint year;
public byte hour;
public byte minute;
public byte rate;
public byte validation;
public byte coupon1;
public byte coupon2;
public byte coupon3;
public byte coupon4;
};
[DllImport("FeeCalculation.dll", CallingConvention = CallingConvention.StdCall,
CharSet = CharSet.Ansi)]
public static extern void FeeCalculation(feeRequest cin,
out feeAnswer cout, string flimit,
string frate, string fwindow, string fincrement, string fbird,
string fparameter,
string fvalidation, string fcoupon);
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
feeRequest freq = new feeRequest();
feeAnswer fans = new feeAnswer();
string flim = "";
string frat = "";
string fwin = "";
string finc = "";
string fbir = "";
string fpar = "";
string fval = "";
string fcoup = "";
freq.day = 26;
freq.month = 2;
freq.year = 2010; //2000 ~ 2099
freq.hour = 20;
freq.minute = 47;
freq.rate = 15;
freq.validation = 1;
freq.coupon1 = 2;
freq.coupon2 = 3;
freq.coupon3 = 4;
freq.coupon4 = 5;
FeeCalculation(freq, out fans, flim, frat, fwin, finc, fbir, fpar, fval, fcoup);
根据约翰的建议:
public static extern void FeeCalculation(feeRequest cin,
out feeAnswer cout,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr flimit,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr frate,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fwindow,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fincrement,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fbird,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fparameter,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fvalidation,
[MarshalAs(UnmanagedType.LPArray)]
IntPtr fcoupon);
...
FeeCalculation(freq, out fans, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
最佳答案
您的问题很可能是您尚未完成互操作声明。正如我之前所说,大多数“字符串”参数实际上都是 out byte[] 参数(或 out struct)
所以你需要做更多类似这样的事情
[DllImport("FeeCalculation.dll", CallingConvention = CallingConvention.StdCall,
CharSet = CharSet.Ansi)]
public static extern void FeeCalculation(feeRequest cin,
out feeAnswer cout,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] flimit,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] frate,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] fwindow,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] fincrement,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] fbird,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] fparameter,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[] fvalidation,
[MarshalAs(UnmanagedType.LPArray, SizeConst=100)]
out byte[]fcoupon);
您可能不关心其他参数,但该函数仍然会尝试写入它们,因此您必须提供虚拟缓冲区,并且缓冲区必须足够大才能容纳输出。 (因此您可能需要更改 SizeConst)。
如果您的函数容忍指向输出的 NULL 指针,那么您可以将不需要的值声明为 IntPtr
并为这些值传递 IntPtr.Zero
。
从长远来看,您确实需要声明该函数想要查看的所有结构,并正确地将它们全部传入。
编辑:好的,您想使用 IntPtr 或 MarshalAs/byte[],但不能同时使用两者。
public static extern void FeeCalculation(feeRequest cin,
out feeAnswer cout,
IntPtr flimit,
IntPtr frate,
IntPtr fwindow,
IntPtr fincrement,
IntPtr fbird,
IntPtr fparameter,
IntPtr fvalidation,
IntPtr fcoupon);
FeeCalculation(freq, out fans, IntPtr.Zero, ...
关于c# - "Attempted to read or write protected memory. This is often an indication that other memory is corrupt"Dll导入C#,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/2345945/