Thank you for your help.
I'd like to call the DLL that my client gave me from my C# program.
The function specification is written in C++ and
Due to my lack of knowledge, I am having trouble knowing how to call from C#.
Thank you for your guidance.
// -- Specifications (in C++)
// functions:
longSample(FOO*foo);
// FOO structural member
Var_1 (type: unsigned char, size 16, In)
Var_2 (type: unsigned char, size 24, In)
Var_3 (Type: unsigned char, Size 128, Out)
// -- Current Code --
// What I'm not sure about:
// Declaration and initialization part of the structure. Can C++ with unsigned char* be C# with Byte[N]...
// The part of the FromHexString function that converts hexadecimal strings to Byte.To be honest, I don't know how to pass the C# string.
class CSample
{
// Call DLL SSampleFunc.dll を.For the argument, pass the structure FOO.
DllImport("SampleFunc.dll", CallingConvention=CallingConvention.Cdecl)
private external static long SampleFunc (FOO foo);
// Define structure
public structure FOO
{
public byte [ ] Var_1;
public byte [ ] Var_2;
public byte [ ] Var_3;
}
public FOO foo;
public CSample()
{
// Initialization of structure
foo.Var_1 = FromHexString("0C08"; // 4-character hexadecimal number
foo.Var_2 = FromHexString ("123412341234123412341234123412341234"; //32 characters in every four digits
foo.Var_3 = new byte [128]; // Buffer to retrieve string from DLL.
}
// Function to convert string to hexadecimal
private static byte [ ] FromHexString(string str)
{
int length = str. Length/2;
byte [ ] bytes = new byte [ length ];
int j = 0;
for (inti=0; i<length;i++)
{
bytes[i] = Convert.ToByte(str.Substring(j,2),16);
j+=2;
}
return bytes;
}
// Function calling DLL
private void ExecSample()
{
long ret = SampleFunc(foo); //ret contains an error code.
}
}
Are Default marshalling or Marshaling data with platform calls helpful?(also the lower tier in the left tree of the page.)
// FOO structural member
Var_1 (type: unsigned char, size 16, In)
Var_2 (type: unsigned char, size 24, In)
Var_3 (Type: unsigned char, Size 128, Out)
The corresponding C# code for is
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)]
public structure Foo{
MarshallAs (UnmanagedType.ByValTStr, SizeConst=16) public string Var_1;
MarshallAs (UnmanagedType.ByValTStr, SizeConst=24) public string Var_2;
MarshallAs (UnmanagedType.ByValTStr, SizeConst=128) public string Var_3;
}
Also
// functions:
longSample(FOO*foo);
C# code corresponding to , but the size of long in the C++ language is environmentally dependent.For example, Visual C++, where long is 4 bytes.Therefore, you must select int which is also 4 bytes in the C# language (long in the C# language is 8 bytes).
[DllImport("SampleFunc.dll", CallingConvention=CallingConvention.Cdecl)]
private external static int SampleFunc(ref FOO foo);
If you declare it correctly as described above, no further action is required because the .NET Framework runtime translates correctly.
// The part of the FromHexString function that converts hexadecimal strings to Byte.To be honest, I don't know how to pass the C# string.
This point is unknown to third parties because the question statement does not indicate what values should be passed.
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