I am trying to migrate a project to VC++ 2010
The project contains the file TabbedMDI.h (by Danial Bowen) which gives the error "named followd by '::' must be a class or namespace name for the line
"typedef typename TClient::TTabCtrl TTabCtrl;"
code snipit follows
template <
class T,
class TClient = CTabbedMDIClient< CDotNetTabCtrl<CTabViewTabItem> >,
class TBase = WTL::CMDIWindow,
class TWinTraits = ATL::CFrameWinTraits>
class ATL_NO_VTABLE CTabbedMDIFrameWindowImpl :
public WTL::CMDIFrameWindowImpl<T, TBase, TWinTraits >
{
public:
// Expose the type of MDI client
typedef typename TClient TClient;
// Expose the type of tab control
typedef typename TClient::TTabCtrl TTabCtrl;
// Member variables
protected:
TClient m_tabbedClient;
Just compiled Daniel's SimpleTabbedMDIDemo sample from Custom Tab Controls, Tabbed Frame and Tabbed MDI with VC2010 Express (WTL 8.1, ATL 8.00 from WinDDK) without problem (except manifest duplication).
Your problem is elsewhere.
[Edit]
Do you use the latest TabbedMDI.h? mine has:
// History (Date/Author/Description):
// ----------------------------------
//
// 2005/07/13: Daniel Bowen
// - Namespace qualify the use of more ATL and WTL classes.
// - CTabbedMDIFrameWindowImpl:
// * Add GetMDITabCtrl
Related
I am trying to build a simple project in Visual Studio 2017 using the template CLR/Empty CLR project .. I have added references to required namespaces, but when I try to inherit "IMessageFilter" class in my class I get below error, What should I do?
class fails to implement interface member function "System::Windows::Forms::IMessageFilter::PreFilterMessage" (declared in "c:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\System.Windows.Forms.dll"
#pragma once
using namespace System;
using namespace System::Windows::Forms;
ref class myClass : public IMessageFilter // this is not accepted by compiler with error
{
public:
myClass();
};
As the error message suggests, you need to implement the PreFilterMessage message function that is required by the IMessageFilter interface:
virtual bool PreFilterMessage(Message% message)
{
// from MSDN: return true to filter the message and stop it from being dispatched; false to allow the message to continue to the next filter or control.
return true;
};
To make it short visual studio 2017 crashes when I am compiling this file:
#pragma once
/// #file
/// #brief Class mbe::HandleBase
#include <unordered_map>
//#include <cassert>
namespace mbe
{
template <class Derived>
class HandleBased abstract
{
public:
typedef unsigned long long int HandleID;
public:
HandleBased();
~HandleBased();
// Maybe rename to GetHandleId()?
HandleID ThisHandleId();
/*{
return id;
}*/
// Maybe rename to FindHandledObject
static Derived * FindPtr(HandleID id)
{
auto it = HandleBased::GetMap().find(id);
if (it == HandleBased::GetMap().end())
return nullptr;
// Should always be save
//assert(dynamic_cast<Derived *>(it->second));
return static_cast<Derived *>(it->second);
}
private:
static HandleID NextHandle()
{
// Every handle will get its own unique id
static HandleID next = 0;
return next++;
}
static std::unordered_map<HandleID, HandleBased *>& GetMap()
{
// Create the static map which will be used to keep track of the Derived handles and their ids
static std::unordered_map<HandleID, HandleBased *> map;
return map;
}
private:
HandleID id; // The id of this handle object
};
#pragma region Template Implementation
template<class Derived>
HandleBased<Derived>::HandleBased() :
id(NextHandle())
{
HandleBased::GetMap()[id] = this;
}
template<class Derived>
HandleBased<Derived>::~HandleBased()
{
auto it = HandleBased::GetMap().find(id);
HandleBased::GetMap().erase(it);
}
template<class Derived>
inline HandleID HandleBased<Derived>::ThisHandleId()
{
return id;
}
#pragma endregion
} // namespace mbe
It compiles fine when the ThisHandleId() function is defined directly below its definition. Is something wrong with my template implementation? I have noticed that the HandleID typedef does not show up in intellisense.
Sometimes VS crashes completely (goes grey and windows displays the message: "Visual Studio 2017 stopped working". Sometimes it just shows that ingame message: "C/C++ optimising compiler stopped working"
Furthermore, I get a ton of compile errors when defining the other functions beneath the HandleBase class or in an inline file. As I said, everything compiles just fine if all functions are implemented just beneath their definition. I have also experimented with removing inline which avoids the crash but gives me even more compile errors. Mosty complete non-sense such as:
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(75): warning C4346: "ThisHandleId": Abhängiger Name ist kein Typ
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(76): note: Präfix mit "typename" zum Angeben eines Typs
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(76): error C2988: Unerkannte Vorlagendeklaration/-definition
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(76): error C2059: Syntaxfehler: ""
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(76): error C2143: Syntaxfehler: Es fehlt ";" vor "{"
2>c:\users\adrian\documents\visual studio 2017\projects\mars base engine ecs 5\mars base engine ecs\handlebase.h(76): error C2447: "{": Funktionsheader fehlt - Parameterliste im alten Stil?
Sorry for the German comments, but u can probably guess what some of them meen. There is stuff like 'depended name is not a type', 'syntax error ""' and 'missing an ; before {'
Also, I don't think removing the inline is a good idea in the first place.
In case you are wondering what the code is for, its described in the acceted answer of this stack overflow question: Using shared_ptr for unique ownership (kind of) - is this good practice?
Hope you can help me with this weird occurence....
Thanks,
Adrian
HandleID is a scoped type. Hence, you will need to use HandleBased<Derived>::HandleID. Furthermore, since HandleID is a dependent type. Hence, you will need to use typename HandleBased<Derived>::HandleID.
Use:
template<class Derived>
inline typename HandleBased<Derived>::HandleID HandleBased<Derived>::ThisHandleId()
{
return id;
}
Alternatively, use trailing return type (Thanks are due to #Angew):
template <class Derived>
auto HandleBase<Derived>::ThisHandleId() -> HandleId
{
return id;
}
That works since trailing return types are within the scope of the class.
How to restrict a template argument of Wrapper to be a Wrapper<Any,MyArray<AnyT>> elegantly?
Don't break content assist (Visual Studio).
High readability. Not use a hacky approach.
For some reasons, most solution love to hack.
Make it obvious at the very first line by using C++ syntax rule. (not just green comment)
As far as I know, there are many solutions, but every solution doesn't meet the criteria.
Workaround 1 (template specialization, fail 1)
template<class T> class MyArray{};
template<class T,class T2> class Wrapper;
template<class T,class T2> class Wrapper<T,MyArray<T2>>{
using Test=int;
};
class B{};
class C{};
int main() {
Wrapper<C,MyArray<B>> wrapper;
return 0;
}
This code is modified from https://stackoverflow.com/a/43518221 (#max66).
Context clue / syntax highlighting of IDE will be confused.
In my case, it marks some correct types as error e.g. :-
class ShowError : public Wrapper<B,MyArray<C>>{
Test n=0; //<-- unknown "Test" (intellisense)
};
Workaround 2 (some hacky field/typedef, fail 2)
template<class T> class MyArray{
public: using MyArrayT=T;
};
template<class T,class T2> class Wrapper{
public: using myT=typename T2::MyArrayT;
//^ assert at compile time
};
This idea come from a comment in https://stackoverflow.com/a/43518295 (#Jarod42)
The class declaration doesn't mention about MyArray, it just uses a hacky (less readable) way (MyArrayT) to enforce that T2 is MyArray.
Workaround 3 (base class, fail 2)
class MyArrayBase{};
template<class T> class MyArray : public MyArrayBase{ };
template<class T,class T2> class Wrapper{
//check something around MyArrayBase *object = new T2();
// or "is_base_of"
};
The code is modified from Restrict C++ Template Parameter to Subclass and C++ templates that accept only certain types.
It has same disadvantage as workaround 2.
It is not obvious for common user.
Workaround 4 (SNIFAE, fail 1)
By adding std::enable_if on the template class declaration (Wrapper), I can get a working hack.
Unfortunately, content assist hate it.
Reference
Here are the other links that I read :-
http://www.informit.com/articles/article.aspx?p=376878 (template template parameter)
restrict a template function, to only allow certain types (not related to template type as a parameter)
You can write a custom type trait is_specialization, as follows:
template<class Type, template<class...> class Template>
struct is_specialization
: std::false_type {};
template<template<class...> class Template, class... TArgs>
struct is_specialization<Template<TArgs...>, Template>
: std::true_type {};
Then you just need to static_assert that is_specialization is true for the given template argument:
template<class T,class T2>
class Wrapper {
static_assert(is_specialization<T2, MyArray>::value, "T2 must be a specialization of MyArray");
};
I'm trying to use boost::fast_pool_allocator in place of the standard allocator and it won't work (ironically with another boost library) because fast_pool_allocator has more than one template parameter even though it claims to be compatible with std::allocator and everything except the first has a default value.
I am trying to pass it as a class template that expects a single template parameter. The specific error:
error: type/value mismatch at argument 3 in template parameter list for "template<class Point, template<class, class> class Container, template<class> class Allocator> class boost::geometry::model::multi_point"
error: expected a template of type "template<class> class Allocator", got "template<class T, class UserAllocator, class Mutex, unsigned int NextSize, unsigned int MaxSize> class boost::fast_pool_allocator"
Is there a way to make this actually work?
Use the following template instead of boost::fast_pool_allocator
template <class T>
using fast_pool_allocator_t = boost::fast_pool_allocator<T>;
This will also work if you are not using C++11.
template <class T>
struct fast_pool_allocator_t : boost::fast_pool_allocator<T>
{ };
i'm having trouble with syntax regarding c++ Windows Forms..
this is how you obviously do it in a regular cpp project: http://www.cplusplus.com/doc/tutorial/structures/
but its not the same in windows forms :/
any help??
THANKS!
btw, i figured it out!
you must create a new class in the project...
call it, Player.h
in the new class, you must instantiate the class like below
to make it a managed class so it fits well with the managed code
in the forms (notice ref class keyword)
struct markedPos
{
int xPos;
int yPos;
};
ref class Player
{
public:
Player()
{
}
protected:
private:
};
then simply in the forms.h file, you must include the new class like any other class:
#include "Player.h"
and all you have to do is make an instance of the player in your forms and it'll work like magic! What i've learned: Do all your heavy lifting in the managed classes outside of the forms... which work just like your regular c++ classes...
cheers!
** You don't need to use managed code! if your getting problems with it, just remove 'ref' before class name