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_AppDomainPtr Load_3 method example?

I am trying to load a C# assembly with _AppDomainPtr Load_3 method. Do you have some example since I get error:
hr = 0x80131533 : A mismatch has occurred between the runtime type of the array and the sub type recorded in the metadata.
Here is a snippet how do I load the assembly:
static void binarray(SAFEARRAY** output, const char* data, size_t size)
{
SAFEARRAYBOUND Bound;
Bound.lLbound = 0;
Bound.cElements = size;
*output = SafeArrayCreate(VT_R8, 1, &Bound);
double HUGEP *pdFreq;
HRESULT hr = SafeArrayAccessData(*output, (void HUGEP* FAR*)&pdFreq);
if (SUCCEEDED(hr))
{
// copy sample values from data[] to this safearray
for (DWORD i = 0; i < size; i++)
{
*pdFreq++ = data[i];
}
SafeArrayUnaccessData(*output);
}
}
And the call:
hr = spDefaultAppDomain->Load_3(output, &spAssembly);
Anyone used that?

Apparently I've found the problem. I was creating a SafeArray of Real numbers. The correct fix for anyone who needs that is:
static void binarray(SAFEARRAY** output, const unsigned char* data, size_t size)
{
SAFEARRAYBOUND Bound;
Bound.lLbound = 0;
Bound.cElements = size;
// VT_I1
*output = SafeArrayCreate(VT_UI1, 1, &Bound);
//VT_R8
unsigned char *pdFreq;
HRESULT hr = SafeArrayAccessData(*output, (void* FAR*)&pdFreq);
if (SUCCEEDED(hr))
{
// copy sample values from data[] to this safearray
for (DWORD i = 0; i < size; i++)
{
*pdFreq++ = data[i];
}
SafeArrayUnaccessData(*output);
}
}

faster way to return data as an array interoping c++

this is a very clean and nice solution to marsahall a struct array from unmanaged C++ code.
it is allmost perfect solution when it comes to simplicity, it took me a while to get to that level of understanding the concept, so that in few lines of code, as you can see C# Main(), i have a populated array of struct ready to be 'harvested'..
typedef struct {
int Id;
BSTR StrVal;
}Package;
extern "C" __declspec(dllexport) void dodata(int requestedLength,int StringSize, Package **Packs){
int count;
count=0;
*Packs = (Package*)LocalAlloc(0, requestedLength * sizeof(Package));
Package *Cur = *Packs;
while(count!= requestedLength)
{
Cur[count].StrVal = NULL;
Cur[count].Id = count;
Cur[count].StrVal=SysAllocString(L"abcdefghij");
Cur[count].StrVal[StringSize-1]=count+'0';
++count;
}
}
C#
[DllImport(#"ExportStructArr.dll", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
public static extern void dodata(int requestedLength, int StringSize, out IntPtr csPkPtr);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct csPk
{
public int V;
[MarshalAsAttribute(UnmanagedType.BStr, SizeConst = 10)]
public string testStr;
}
static void Main(string[] args){
int ArrL = 16000;
csPk[] Cpk = new csPk[ArrL];
IntPtr CpkPtr = IntPtr.Zero;
int szPk = Marshal.SizeOf(typeof(csPk));
dodata(ArrL, 10, out CpkPtr);
}
now all i have to do is :
for (int i = 0; i < Cpk.Length; i++)
{
Cpk[i] = (csPk)Marshal.PtrToStructure(new IntPtr(CpkPtr.ToInt32() + (szPk * i)), typeof(csPk));
}
the solution is quite easy as you can see
the question is using unsafe or any kind of transformation to the data, even going down to bytes...
how could i optimize it to perform better returning the data ?
Edit:
links i have tried to learn from other answers here in SO:
answer from Hans Passant
answer from AbdElRaheim
answer from supercat
also tried google : wikipedia , a github post by stephentoub

this is a complete blazing fast solution to populate a list of objects, i did my best
and i will be happy to have comments and suggestions.
c++
typedef struct _DataPacket
{
BSTR buffer;
UINT size;
} DataPacket;
extern "C" __declspec(dllexport) void GetPacksUnsafe( int size, DataPacket** DpArray )
{
int szr = size;int count=0;
*DpArray = (DataPacket*)CoTaskMemAlloc( szr * sizeof( DataPacket ));
if ( DpArray != NULL )
{
DataPacket* CurPack = *DpArray;
for ( int i = 0; i < szr; i++, CurPack++ )
{
CurPack->size = i;
CurPack->buffer = SysAllocString(L"SomeText00");
CurPack->buffer[9]=i+'0';
}
}
}
C#
[DllImport(#"ExportStructArr.dll", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
public static extern void GetPacksUnsafe(int size, PackU** outPackUArr);
[StructLayout(LayoutKind.Sequential)]
public unsafe struct PackU
{
public char* StrVal;
public int IntVal;
}
public static unsafe List<PackU> PopulateLstPackU(int ArrL)
{
PackU* PackUArrOut;
List<PackU> RtLstPackU = new List<PackU>(ArrL);
GetPacksUnsafe(ArrL, &PackUArrOut);
PackU* CurrentPack = PackUArrOut;
for (int i = 0; i < ArrL; i++, CurrentPack++)
{
RtLstPackU.Add(new PackU(){ StrVal = CurrentPack->StrVal, IntVal=CurrentPack->IntVal});
}
Marshal.FreeCoTaskMem((IntPtr)PackUArrOut);
for (int i = 0; i < 10; i++)
{
Console.WriteLine("{0}", new string(RtLstPackU[i].StrVal));
}
return RtLstPackU;
}
using the code is as simple as it could possibly be
static unsafe void Main(string[] args)
{
int ArrL = 100000;
List<PackU> LstPackU;
LstPackU = PopulateLstPackU(ArrL);
}
there you have a list of custom data as fast as a bullet..
EDIT
using pointers instead of strings :
typedef struct _DataPackCharPnt
{
char* buffer;
UINT IntVal;
} DataPackCharPnt;
extern "C" __declspec(dllexport) void GetPacksPnt( int size, DataPackCharPnt** DpArrPnt )
{
int count = 0;
int TmpStrSize = 10;
*DpArrPnt = (DataPackCharPnt*)CoTaskMemAlloc( size * sizeof( DataPackCharPnt ));
DataPackCharPnt* CurPackPnt = *DpArrPnt;
char dummyStringDataObject[]= "abcdefgHi";
for ( int i = 0; i < size; i++,CurPackPnt++ )
{
dummyStringDataObject[9] = i+'0';
CurPackPnt->IntVal=i;
CurPackPnt->buffer = (char*)malloc(sizeof(char)*TmpStrSize);
strcpy(CurPackPnt->buffer, dummyStringDataObject);
}
}
reduced the time taken from 11 to 7 ms populating 100k elements
is there any part of creating the buffer i could omit ?
the duty of dummyStringDataObject is to simulate work, say getting a file name then set the buffer with its value, so except for this extra time which is the whole purpose of this function, to return some unknown values and lengths of the strings...
could you optimize it even further ?

How to convert the IntPtr to an array?

How to convert the IntPtr to an array. Actually I called the function from unmanaged dll. It returns IntPtr. Now I need to convert it to an array. Please any one give an idea.Code snippet is below.
Unmanaged function declared
[DllImport("NLib.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern unsafe IntPtr N_AllocPt1dArray(NL_INDEX n, ref stacks S);
Calling the function
void Function1()
{
IntPtr PPtr=N_AllocPt1dArray(n, ref S);
}
Now I need to convert PPtr to an array(array is demo[]).where demo is defined by
public unsafe struct demo
{
public int x ;
public int y ;
public int z ;
}demo DEMO;

Try this:
array[0] = (demo)System.Runtime.InteropServices.Marshal.PtrToStructure(PPtr , typeof(demo));
UPDATE :
Solution 2 of this page is what you need.

It depends of what type of data you are pointing to, the next code get an array of strings from an IntPtr:
nstring is the number of elements you expect to get.
You can modify the code to satisfy your needs, but this can give you an idea of how to retrive data from an IntPtr in an unmaganed block code.
private string[] ConvertIntPtrToStringArray(IntPtr p, int nstring)
{
//Marshal.ptr
string[] s = new string[nstring];
char[] word;
int i, j, size;
unsafe
{
byte** str = (byte**)p.ToPointer();
i = 0;
while (i < nstring)
{
j = 0;
while (str[i][j] != 0)
j++;
size = j;
word = new char[size];
j = 0;
while (str[i][j] != 0)
{
word[j] = (char)str[i][j];
j++;
}
s[i] = new string(word);
i++;
}
}
return s;
}
cheers,
Kevin

Updating an C dll struct array and its elements values from C# code using dllimport

I have C code which will be build as a dynamic library (DLL) , which i would like
to call C function from C# using dLL created from the C code
C code :
struct data
{
char data_val1[100];
float data_val2;
float data_val3[50];
};
typedef struct data data;
#ifdef __cplusplus
extern "C" __declspec(dllexport) void cfun_call(data *pdata,long count);
#endif
#ifdef __cplusplus
extern "C"
{
#endif
__declspec(dllexport) void cfun_call(data *pdata,long count)
{
int x = 0;
for(x=0;x<count;x++)
{
data[x].data_val2 = (pdata->data_val3[49] + pdata->data_val3[48]) / 2.0;
}
}
#ifdef __cplusplus
}
#endif
Here i wanted to import the function "cfun_call" in C# code, and pass values to the fucntion call
and manipulate the passed values in C function from the dll and wanted to display the updated values
back to the C# code and display it, Since my expertise in C# is limited i need some help to solve this issue
C# code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
class Program
{
public class data
{
public char[] data_val1 = new char[100];
public float data_val2;
public float[] data_val3 = new float[50];
};
[DllImport("mycdll.dll", EntryPoint = "cfun_call", CallingConvention = CallingConvention.Cdecl, ExactSpelling = false)]
// void cfun_call(data *pdata,long count); //C function for reference
public static extern void cfun_call([In, Out] data[] ouputdata, long count);
static void Main(string[] args)
{
data[] objData = new data[10];
for (int i = 0; i < 10; i++)
{
//Fill the data in objitemData
objData[i] = new objData();
for (int j = 0; j < 100; j++)
{
objData[i].data_val1[j] = '\0';
}
for (int k = 0; k < 50; k++)
{
objData[i].data_val3[k] = 20.00;
}
objData[i].data_val2 = 0.00;
}
cfun_call(objData,10); //Making call to C dll function
for (int i = 0; i < 10; i++)
Console.WriteLine("{0} ", objData[i].data_val2);
Console.WriteLine("");//new line
Console.ReadLine();
}
}
Here the values (objData) passed from C# function is not updated by using the C dll fucntion , I am not sure why.
Can anyone point me to right direction ?
Edit 1:
I have updated code as suggested ,
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct data
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)]
public char[] data_val1;
public float data_val2;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 50)]
public float[] data_val3;
};
Initialized struct elements like below ,
data[] objData = new data[10];
for (int i = 0; i < 10; i++)
{
//Fill the data in objitemData
objData[i] = new objData();
for (int j = 0; j < 100; j++)
{
objData[i].data_val1[j] = '\0'; //I am getting exception here
}
for (int k = 0; k < 50; k++)
{
objData[i].data_val3[k] = 20.00;
}
objData[i].data_val2 = 0.00;
}
Runtime i am getting null ptr exception , like
An unhandled exception of type 'System.NullReferenceException' occurred in mybinary.exe
Additional information: Object reference not set to an instance of an object.
How to initialize the struct array elements properly in manged code ?
Edit 2:
Hi one more question , when i add , objData[i].data_val3[k] = randomData; //randomvalues, It is not updated when making cfun_call while using contnt value it is updated why ?

Your translation of the struct is incorrect. You need it to be like so:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct data
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)]
public char[] data_val1;
public float data_val2;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 50)]
public float[] data_val3;
};
You have to make this a struct since you need to pass an array of values. Your declaration using class leads to you passing an array of references.
You will need to initialize the arrays explicitly now. That might look like so:
data[] objData = new data[10];
for (int i = 0; i < 10; i++)
{
objData[i].data_val1 = new char[100];
objData[i].data_val2 = 0.00;
objData[i].data_val3 = new float[50];
for (int k = 0; k < 50; k++)
{
objData[i].data_val3[k] = 20.0f;
}
}
Further, C++ long is 32 bits wide, but C# long is 64 bits wide. You therefore have a mismatch. Your p/invoke should be:
[DllImport("mycdll.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void cfun_call(
[In, Out] data[] ouputItem_data,
int count
);

Passing string arrays from COM to C#

I need to access C# methods in a COM dll via COM-like interface. One of the method requires an array of strings to be passed as input.
Am creating a SAFEARRAY and passing it to the COM Interop. However, this does not seem to be working, as I see an exception in the interop layer. (System.Runtime.InteropServices.SafeArrayTypeMismatchException).
Obviously, there seems to be a difference in type being expected.
Pasting the code here:
C# method to be invoked:
public long DoIt3(int nFiles, string[] fileNames);
C++ code invoking the same:
int _tmain()
{
TCHAR *fileNames[128] = { TEXT("C:\\Program Files\\IBM\\RTC.NET"),
TEXT("C:\\KIRAN\\Work\\RFT"), TEXT(".\\bin\\Debug") };
SAFEARRAY *pSA = CreateSafeStringArray(3, fileNames);
_tprintf(TEXT("%d"), pIManaged->DoIt3(3, pSA));
SafeArrayDestroy(pSA);
}
static SAFEARRAY *CreateSafeStringArray(long nElements, TCHAR *elements[])
{
SAFEARRAYBOUND saBound[1];
saBound[0].cElements = nElements;
saBound[0].lLbound = 0;
SAFEARRAY *pSA = SafeArrayCreate(VT_VARIANT, 1, saBound);
if (pSA == NULL)
{
return NULL;
}
for (int ix = 0; ix < nElements; ix++)
{
VARIANT v;
VariantInit(&v);
v.vt = VT_BSTR;
v.bstrVal = elements[ix];
long rgIndicies[1];
rgIndicies[0] = ix + saBound[0].lLbound;
HRESULT hr = SafeArrayPutElement(pSA, rgIndicies, &v);
_tprintf(TEXT("%d"), hr);
VariantClear(&v);
}
return pSA;
}
Any ideas/suggestions are welcome.

I figured it out! The following code works:
static SAFEARRAY *CreateSafeStringArray(long nElements, TCHAR *elements[])
{
SAFEARRAYBOUND saBound[1];
saBound[0].cElements = nElements;
saBound[0].lLbound = 0;
SAFEARRAY *pSA = SafeArrayCreate(VT_BSTR, 1, saBound);
if (pSA == NULL)
{
return NULL;
}
for (int ix = 0; ix < nElements; ix++)
{
BSTR pData = SysAllocString(elements[ix]);
long rgIndicies[1];
rgIndicies[0] = saBound[0].lLbound + ix;
HRESULT hr = SafeArrayPutElement(pSA, rgIndicies, pData);
_tprintf(TEXT("%d"), hr);
}
return pSA;
}
Thanks for all your suggestions!

In the case of an array of BSTR strings, you can set the BSTR values directly on your array, and also you need to allocate memory for your BSTR elements, you could use ATL/MFC CString for that:
...
psa = SafeArrayCreate( VT_BSTR, 1, saBound);
HRESULT hr = SafeArrayLock( psa );
//TODO: test for hr success
if (pSA == NULL)
{
return NULL;
}
for (int ix = 0; ix < nElements; ix++)
{
long rgIndicies[1];
rgIndicies[0] = ix + saBound[0].lLbound;
CString tempstr(elements[ix]);
((BSTR*)psa->pvData)[ix] = tempstr.AllocSysString();
_tprintf(TEXT("%d"), hr);
}
hr = SafeArrayUnlock( psa );
//TODO: test for hr success
...