Such as mfc, it should add
DECLARE_SERIAL(CGraph)
If I a have a class,
class A
{
int a,b;
};
I can store the value of a and b to a file ,then read it.
So I couldn't understand why DECLARE_SERIAL(CGraph) used.
The DECLARE_SERIAL and IMPLEMENT_SERIAL macros are only necessary for classes derived from CObject that you wish to serialize polymorphically using the framework provided by MFC.
If your class is not derived from CObject and/or you do not wish to use MFC's serialization polymorphically (i.e. via a pointer to CObject), then of course you can implement your own solution as you rightly say.
For example, DECLARE_SERIAL(CMyClass) expands to the following code that goes in your class declaration
protected:
static CRuntimeClass* __stdcall _GetBaseClass();
public:
static CRuntimeClass classCMyClass;
static CRuntimeClass* __stdcall GetThisClass();
virtual CRuntimeClass* GetRuntimeClass() const;
static CObject* __stdcall CreateObject();
friend CArchive& __stdcall operator>>(CArchive& ar, CMyClass* &pOb);
and IMPLEMENT_SERIAL(CMyClass, CObject, VERSIONABLE_SCHEMA | 1) expands to the following code that goes in the cpp file
CObject* __stdcall CMyClass::CreateObject()
{
return new CMyClass;
}
extern AFX_CLASSINIT _init_CMyClass;
CRuntimeClass* __stdcall CMyClass::_GetBaseClass()
{
return (CObject::GetThisClass());
}
__declspec(selectany) CRuntimeClass CMyClass::classCMyClass =
{
"CMyClass", sizeof(class CMyClass), (0x80000000) | 1,
CMyClass::CreateObject, &CMyClass::_GetBaseClass, 0, &_init_CMyClass
};
CRuntimeClass* __stdcall CMyClass::GetThisClass()
{
return ((CRuntimeClass*)(&CMyClass::classCMyClass));
}
CRuntimeClass* CMyClass::GetRuntimeClass() const
{
return ((CRuntimeClass*)(&CMyClass::classCMyClass));
}
AFX_CLASSINIT _init_CMyClass((CMyClass::GetThisClass()));
CArchive& __stdcall operator>>(CArchive& ar, CMyClass* &pOb)
{
pOb = (CMyClass*) ar.ReadObject((CMyClass::GetThisClass()));
return ar;
}
As it says in MSDN it is also possible to use serialization without using the above macros:
Related
//MyWrapper.h
#include "arithmetic.h"
#include "mathematics.h"
namespace MyWrapper {
public ref class ClassA
{
public:
ClassA();
~ClassA();
int add(int, int);
private:
MyEngine::Arithmetic *nativeClassA;
}
public ref class ClassB
{
public:
ClassB(ClassA^ arith);
~ClassB();
int pow(int, int);
private:
MyEngine::Mathematics *nativeClassB;
}
}
//MyWrapper.cpp
#include "MyWrapper.h"
My::ClassA::ClassA()
{
nativeClassA = new MyEngine::Arithmetic();
}
My::ClassA::~ClassA()
{
delete nativeClassA;
}
int My::ClassA::add(int a, int b)
{
return nativeClassA->add(a, b);
}
My::ClassB::ClassB(ClassA^ classA)
{
nativeClassB = new MyEngine::Mathematics(classA->nativeClassA); //***Error***
}
My::ClassB::~ClassB()
{
delete nativeClassB;
}
int My::ClassB::pow(int a, int b)
{
int result = nativeClassB->pow(a, b);
return result;
}
Here, Mathematics class need to init with Arithmetic class.
But nativeClassA is private variable in ClassA.
So nativeClassB = new MyEngine::Mathematics(classA->nativeClassA); , it will occurs compile error.
So I changed the nativeClassA to public.
But at that time, nativeClassA will export to c#.
I don't want to export nativeClassA variable to c#.
How can I fix it?
Thanks in advice.
Since you're writing a managed class, you can use all the access modifiers that C# has. This seems like a perfect scenario for internal. (The linked documentation is for C#, but it's the same keyword in C++/CLI.)
typedef struct pt_input_bir
{
PT_BYTE byForm;
union {
PT_BIR *pBIR; ///< Used when byForm = PT_FULLBIR_INPUT */
PT_LONG lSlotNr; ///< Used when byForm = PT_SLOT_INPUT */
PT_BYTE abyReserved[20]; /** For future use */
} InputBIR;
} PT_INPUT_BIR
typedef struct pt_bir {
PT_BIR_HEADER Header;
PT_BYTE Data[1];
} PT_BIR
typedef struct pt_bir_header {
PT_DWORD Length;
PT_BYTE HeaderVersion;
PT_BYTE Type;
PT_WORD FormatOwner;
PT_WORD FormatID;
PT_CHAR Quality;
PT_BYTE Purpose;
PT_DWORD FactorsMask;
} PT_BIR_HEADER
and the C function is
PT_STATUS StoreFinger (
IN PT_CONNECTION hConnection,
IN PT_INPUT_BIR *pTemplate,
OUT PT_LONG *plSlotNr
)
Now I need to do the wrapper for the above C function in C#.
How should I marshal the PT_INPUT_BIR* structure and how should I unmarshal it after return of this function?
Please help me to solve this.
/********************** FOR MORE DETAIL ABOUT THIS QUESTION**************************/
C struct and function are defined in above. pls refer there.
C# Struct :
For C# struct declaration i have maintatined two struct for the one C struct. bcz one is for setting the values and another one id for passing to c function.
C# app struct:
[StructLayout(LayoutKind.Sequential)]//for app
public struct FPINPUTBIR
{
public byte byForm;
public InputBIRType InputBIR;
}
[StructLayout(LayoutKind.Sequential)] // here when i use explicit it throws exception so i removed it.
public struct InputBIRType
{
// [FieldOffset(0)]
public FPBIR pBIR;
//[FieldOffset(0)]
public int lSlotNr;
//[FieldOffset(0)]
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 20)]
public byte[] abyReserved;
}
C# wrapper struct:
[StructLayout(LayoutKind.Sequential)]
public struct FP_INPUTBIR
{
public byte byForm;
public IntPtr mIPBIR;
}
[StructLayout(LayoutKind.Explicit, Size = 20, CharSet = CharSet.Ansi)]
public struct Input_BIRType
{
[FieldOffset(0)]
public IntPtr mBIR;
[FieldOffset(0)]
public int lSlotNr;
//[FieldOffset(8)]
//[MarshalAs(UnmanagedType.ByValArray, SizeConst = 20)]
//public byte[] abyReserved;
}
finally i will copy the value from the C# app struct to wrapper struct before the call the C fun()
2a) C# App Side Code is :
//here mAppMemory is already known value
FPINPUTBIR lfipdata = new FPINPUTBIR();
FPDATA lfpdata = new FPDATA();
lfipdata.byForm = (byte)eFPVerifyBy.FULLBIR_INPUT;
lfipdata.InputBIR = new InputBIRType();
lfipdata.InputBIR.abyReserved = new byte[20];
lfipdata.InputBIR.pBIR.Data = new byte[mAppMemory[listBox2.SelectedIndex].Header.Length];
Array.Copy(mAppMemory[listBox2.SelectedIndex].Data, lfipdata.InputBIR.pBIR.Data, mAppMemory[listBox2.SelectedIndex].Header.Length);
lfipdata.InputBIR.pBIR.Header = mAppMemory[listBox2.SelectedIndex].Header;
Verify(ref lfipdata); //calling from C# APP side to C# wrapper
C# wrapper side:
public int Verify(ref FPINPUTBIR apStoredTemplate )
{
// i passed the args (apStoredTemplate ) but throws exception struct mismatch with C struct.
//here i don't know what should i do.
CDLL.StoreFinger(..,ref apStoredTemplate,.. ); //pls refer the C function above
}
Questions:
Do i really need two C# structures for this.
what should i do inside the C# wrapper function. please remeber i have two C# struct with diff members.
Thanks.
You just need a little extension on what you used in the previous question for PT_BIR. There we marshalled that variable length struct as byte[]. You can use the same code to generate the byte array, and I won't revisit that.
Next you need the union. That is:
[StructLayout(LayoutKind.Explicit, Size = 20)]
public struct PT_INPUT_BIR_UNION
{
[FieldOffset(0)]
public IntPtr pBIR;
[FieldOffset(0)]
public int lSlotNr; // I'm guessing what PT_LONG is
}
No need to declare the reserved part of the union. The size takes care of that.
Then PT_INPUT_BIR is
[StructLayout(LayoutKind.Sequential)]
public struct PT_INPUT_BIR
{
Byte byForm;
PT_INPUT_BIR_UNION InputBirUnion;
}
Then you need to use GCHandle to pin the PT_BIR byte array. Let's keep to the same naming as used at that question, and assume that the PT_BIR is held in a byte[] variable named data.
GCHandle handle = GCHandle.Alloc(data, GCHandleType.Pinned);
try
{
PT_INPUT_BIR inputBir;
inputBir.byForm := ...;
inputBir.InputBirUnion.pBIR = handle.AddrOfPinnedObject();
// now call StoreFinger passing ref inputBir
}
finally
{
handle.Free();
}
When you declare StoreFinger the PT_BIR* parameter should be declared as ref PT_BIR.
I've been given a third party C/C++ library (.dll, .lib, .exp and .h) that I need to use in our C# app.
ThirdPartyLibrary.h contains...
class AClass {
public:
typedef enum {
green = 7,
blue = 16
} Color;
virtual int GetData()=0;
virtual int DoWork(Color, char *)=0;
};
void * Func1(int, AClass **aClass);
In my C++/CLI code I have done this...
#include "ThirdPartyLibrary.h"
using namespace System;
using namespace System::Runtime::InteropServices;
namespace Wrapper {
public ref class MyBridgeClass
{
private:
AClass* pAClass;
public:
// C# code will call this method
void AMethod (int x)
{
int y = x+10;
Func1 (y, &(this->pAClass)); // <-- error!
}
}
}
I get a build error that reads...
cannot convert parameter 2 from 'cli::interior_ptr<Type>' to 'AClass **'
with
[
Type=AClass *
]
Cannot convert a managed type to an unmanaged type
Any ideas? Maybe I need #pragma manage/unmanged tags in my C++/CLI?
The reason you're getting that error is because of how managed memory works.
In your managed class, you've got a pointer defined. The address of that pointer is part of the managed object, and can change when the garbage collector runs. That's why you can't just pass &pAClass to the method, the GC can change what that address actually is.
There's a couple things you can do to fix this:
You could create an unmanaged helper class to hold the AClass* member. I'd do this if that pointer needs to stay valid beyond the invocation of this method, or if you have a lot of unmanaged pointers to hold.
struct UnmanagedHolder
{
AClass* pAClass;
};
public ref class MyBridgeClass
{
private:
// must create in constructor, delete in destructor and finalizer.
UnmanagedHolder* unmanaged;
public:
// C# code will call this method
void AMethod (int x)
{
int y = x+10;
Func1 (y, &(this->unmanaged->pAClass));
}
};
If you only need the pointer to be valid within AMethod, and the pointer doesn't need to remain valid after the call to Func1, then you can use a pin_ptr.
void AMethod (int x)
{
int y = x+10;
pin_ptr<AClass*> pin = &(this->pAClass);
Func1 (y, pin);
}
I have this code for the C# in Visual Studio 2012.
public Task SwitchLaserAsync(bool on)
{
return Task.Run(new Action(() => SwitchLaser(on)));
}
This will execute SwitchLaser method (public nonstatic member of a class MyClass) as a task with argument bool on.
I would like to do something similar in managed C++/CLI. But I am not able to find out any way how to run a task, which will execute a member method taking one parameter.
Current solution is like this:
Task^ MyClass::SwitchLaserAsync( bool on )
{
laserOn = on; //member bool
return Task::Run(gcnew Action(this, &MyClass::SwitchLaserHelper));
}
Implementation of SwitchLaserHelper function:
void MyClass::SwitchLaserHelper()
{
SwitchLaser(laserOn);
}
There must be some solution like in C# and not to create helper functions and members (this is not threadsafe).
There isn't yet any way to do this.
In C# you have a closure. When your C++/CLI compiler was written, the standardized syntax for closures in C++ was still being discussed. Thankfully, Microsoft chose to wait and use the standard lambda syntax instead of introducing yet another unique syntax. Unfortunately, it means the feature isn't yet available. When it is, it will look something like:
gcnew Action([this, on](){ SwitchLaser(on) });
The current threadsafe solution is to do what the C# compiler does -- put the helper function and data members not into the current class, but into a nested subtype. Of course you'll need to save the this pointer in addition to your local variable.
ref class MyClass::SwitchLaserHelper
{
bool laserOn;
MyClass^ owner;
public:
SwitchLaserHelper(MyClass^ realThis, bool on) : owner(realThis), laserOn(on) {}
void DoIt() { owner->SwitchLaser(laserOn); }
};
Task^ MyClass::SwitchLaserAsync( bool on )
{
return Task::Run(gcnew Action(gcnew SwitchLaserHelper(this, on), &MyClass::SwitchLaserHelper::DoIt));
}
The C++ lamdba syntax will simply create that helper class for you (currently it works for native lambdas, but not yet for managed ones).
Here's generic code I wrote this afternoon which might help (although it's not an exact match for this question). Maybe this will help the next person who stumbles onto this question.
generic<typename T, typename TResult>
ref class Bind1
{
initonly T arg;
Func<T, TResult>^ const f;
TResult _() { return f(arg); }
public:
initonly Func<TResult>^ binder;
Bind1(Func<T, TResult>^ f, T arg) : f(f), arg(arg) {
binder = gcnew Func<TResult>(this, &Bind1::_);
}
};
ref class Binder abstract sealed // static
{
public:
generic<typename T, typename TResult>
static Func<TResult>^ Create(Func<T, TResult>^ f, T arg) {
return (gcnew Bind1<T, TResult>(f, arg))->binder;
}
};
Usage is
const auto f = gcnew Func<T, TResult>(this, &MyClass::MyMethod);
return Task::Run(Binder::Create(f, arg));
Here's the working answer.. Have tested it.. Passing an argument (int) to the action sampleFunction.
#include "stdafx.h"
#include "CLRSamples.h"
using namespace System;
using namespace System::Threading;
using namespace System::Threading::Tasks;
using namespace System::Collections;
using namespace System::Collections::Generic;
void CLRSamples::sampleFunction(Object^ number)
{
Console::WriteLine(number->ToString());
Thread::Sleep((int)number * 100);
}
void CLRSamples::testTasks()
{
List<Task^>^ tasks = gcnew List<Task^>();
for (int i = 0; i < 10; i++)
{
tasks->Add(Task::Factory->StartNew((Action<Object^>^)(gcnew Action<Object^>(this, &CLRSamples::sampleFunction)), i));
}
Task::WaitAll(tasks->ToArray());
Console::WriteLine("Completed...");
}
int main(array<System::String ^> ^args)
{
CLRSamples^ samples = gcnew CLRSamples();
samples->testTasks();
Console::Read();
return 0;
}
I had a similar problem when I wanted to provide a parameter to a task executing a method which does not return a value (retuns void). Because of that Func<T, TResult> was not an option I could use. For more information, please check the page Using void return types with new Func.
So I ended up with a solution where I created a helper class
template <typename T>
ref class ActionArguments
{
public:
ActionArguments(Action<T>^ func, T args) : m_func(func), m_args(args) {};
void operator()() { m_func(m_args); };
private:
Action<T>^ m_func;
T m_args;
};
which is using Action<T> delegate to encapsulate a method that has a single parameter and does not return a value.
I would then use this helper class in a following way
ref class DisplayActivationController
{
public:
DisplayActivationController();
void StatusChanged(EventArgs^ args) { };
}
Action<EventArgs^>^ action =
gcnew Action<EventArgs^>(this, &DisplayActivationController::StatusChanged);
ActionArguments<EventArgs^>^ action_args =
gcnew ActionArguments<EventArgs^>(action, args);
Threading::Tasks::Task::Factory->
StartNew(gcnew Action(action_args, &ActionArguments<EventArgs^>::operator()));
Approach using the helper class is probably not the most elegant solution, but is the best one I could find to be used in C++/CLI which does not support lambda expressions.
If you are using c++/ CLR, then make a C# dll and add reference to it
namespace TaskClrHelper
{
public static class TaskHelper
{
public static Task<TResult> StartNew<T1, TResult>(
Func<T1, TResult> func,
T1 arg)
=> Task.Factory.StartNew(() => func(arg));
public static Task<TResult> StartNew<T1, T2, TResult>(
Func<T1, T2, TResult> func,
T1 arg1, T2 arg2)
=> Task.Factory.StartNew(() => func(arg1, arg2));
}
}
bool Device::Stop(int timeout)
{
_ResetEvent_Running->Set();
return _ResetEvent_Disconnect->WaitOne(timeout);
}
Task<bool>^ Device::StopAsync(int timeout)
{
auto func = gcnew Func<int, bool>(this, &Device::Stop);
return TaskClrHelper::TaskHelper::StartNew<int,bool>(func,timeout);
}
I'm trying to write a wrapper for a very simple std::pair<std::string, float> in C++/CLI but I get the error message: no instance of constructor "std::pair<_Ty1, _Ty2>::pair [with _Ty1=std::string, _Ty2=float]" matches the argument list, argument types are: (std::string, float)
What am I doing wrong and why doesn't std::string match std::string?
#include <msclr\marshal_cppstd.h>
#include <string>
using namespace System;
using namespace System::Runtime::InteropServices;
typedef std::pair<std::string, float> Parameter;
static std::string StringToNative(String^ str)
{
msclr::interop::marshal_context context;
return context.marshal_as<std::string>(str);;
}
public ref class CLIParameter
{
public:
CLIParameter(System::String^ name, float value) : _name(name), _value(value) {};
Parameter toNativeParameter()
{
return Parameter(StringToNative(_name), _value);
}
private:
System::String^ _name;
float _value;
};
int main()
{
CLIParameter^ par = gcnew CLIParameter("test", 1);
}
Your method toNativeParameter() is incorrect. It should be defined as follows:
Parameter toNativeParameter()
{
// copy the floating point value from the managed heap to the local stack
float value = _value;
// create the pair
return std::make_pair(StringToNative(_name), value);
}
Notice that you should use std::make_pair to create the actual pair. In addition, a key step to make this work is copying the floating point value from the managed heap into the local stack. The reason is that native functions such as std::make_pair cannot create native references to an object from the managed (garbage collected) heap i.e. a member of a managed class.