Managed C++/CLI

8-Apr-10 4:59

Hi,

I'm quite new to C++/CLI and ran into a problem. I'm trying to get data from some textboxes on a form, for use in another source file. I think the best way to do this is to make a method in the form code which gets the textbox data and passes is to the source file when called. However, somehow I cannot get this working. Can anyone maybe point me in the right direction?

Any help would be great!

Andreoli Carlo13-Apr-10 0:41

13-Apr-10 0:41

is there some reletion between the first form and the second form....
do the first form generate the second form or the second form generate the first?

KlaasVersteeg13-Apr-10 1:31

13-Apr-10 1:31

Actually the code in which the data from the form is needed is no form itself. There is no relation between the form and the source file in which the data from the form is to be used.
I hope this makes it clear.

Andreoli Carlo13-Apr-10 2:22

13-Apr-10 2:22

google for this....and you'll find the solution

[DllImport("user32.dll")]
extern IntPtr FindWindow(String^ lpClassName, String^ lpWindowName);

once you have the pointer to the data's form, you have several way to get the data

KlaasVersteeg13-Apr-10 2:25

object to string (with 15 digit precision if decimal) [modified]

13-Apr-10 2:25

I'll have a go with that at Google. Thanks for your help!

T21028-Apr-10 4:49

T2102

8-Apr-10 4:49

I want to convert an object to a string and if it is a float, double, etc,,, then I would want to set the precision like I can with a printf statement.
What would be an efficient way to test if a System::Object is some decimal type and then set the precision? Thanks

//I've tried the following, but it does not work properly
switch (System::Type::GetTypeCode(columnYValues[n]->GetType())) {
case System::TypeCode::Decimal:
case System::TypeCode::Double:
case System::TypeCode::Single:
X=System::String::Format( "{0:f15}", columnYValues[n]->ToString() );
break;
default:
X = columnYValues[n]->ToString();
}

I am trying to create pivot tables using decimal headers and half of the time it does not work because of C++ .NET or ADO .NET's string conversions and zero tolerance.

modified on Friday, April 9, 2010 2:38 AM

Re: object to string (with 15 digit precision if decimal)

Andreoli Carlo13-Apr-10 0:39

Invoking Event Handlers Programmatically?

13-Apr-10 0:39

try with the following:

System::Convert::ToInt32
System::Convert::ToDouble
System::Convert::To......

TheBerk7-Apr-10 11:18

TheBerk

7-Apr-10 11:18

I'm not sure if this is possible, since I haven't been able to find much of anything on it, but I'm looking to call a control's event handlers programmatically. What I have is an application with multiple windows. Across the top of the app in a tool bar and one of those buttons, lets say copy, must preform that action on whichever window is currently active. They only way I can think to do this (as for various reasons the only way I can get these windows is as an instance of System::Windows::Forms::Control) is to trigger its Key Pressed event handler with 'Ctrl+C', but I can't seem to get access to it. Is this even possible? And if so how?

Thanks!

Andreoli Carlo7-Apr-10 23:04

7-Apr-10 23:04

So you press the button and want for example that in windows#1 it copy something, in windows#2 it copy something and so on....
if the toolbar is the 'creator' of the windows# you can use a list to have the pointer of all of the window you have created....then you can loop through the list and see which windows is active, and then call the specified function on that window....do i understand your problem?

TheBerk8-Apr-10 3:55

TheBerk

8-Apr-10 3:55

Right, if the button is pushed the copy event is called in whatever window is currently active. I have the a active window part already, from the tool bar I have an 'active Window' pointer, so thats not a problem, but since that pointer is just a System::Windows::Forms::Control pointer, I don't have access to any of the controls specially written "Copy" functions, just the standard Forms::Control functions. All of the controls which have some sort of copy functionality already can do it through "Ctrl+C" so I wanted to know if I could programmatically trigger its KeyPress event handler to use their copy functionality. I'm just not sure how to trigger an event like keypress via code.

Andreoli Carlo8-Apr-10 20:54

8-Apr-10 20:54

loaak at
http://msdn.microsoft.com/en-us/library/system.windows.forms.sendkeys.aspx[^]

also...you black boxes give you the possibilities only to use the "control+c" key or they provide also some public function to do the operations? if they give also public function you can always try to static_cast or dynamic_cast the Control pointer...if this is your case this is far better than trigger the ctr+c command

Getting an article published on CodeProject should be easier and faster for Bronze and Silver authors.

Luc Pattyn8-Apr-10 4:52

Luc Pattyn

8-Apr-10 4:52

Hi,

IMO you should not attempt to call an event handler explicitly; one reason is you would have to provide fake parameters, sender wouldn't be a problem, the particular EventArgs may prove more difficult to fake. Unless of course you're absolutely sure the handler doesn't (and never will) use its parameters.

There are two alternatives I would recommend:
1. some events can be triggered by calling an appropriate method, e.g. Button.PerformClick().
2. when the functionality of an event handler is also useful outside the normel event handling, refactor it into a separate method, call that from the event handler, and from anywhere else you'd like to call it.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

TheBerk8-Apr-10 5:05

TheBerk

8-Apr-10 5:05

Thanks for the reply! My problem I have with you're second suggestion is that some of the windows contain third party controls, and are basically black boxes, so I cannot move that functionality into a seperate method. You're first suggestion seems promising, is there a way to do something like that, but with key stokes instead of Button.PerformClick()? Thanks!

Getting an article published on CodeProject should be easier and faster for Bronze and Silver authors.

Luc Pattyn8-Apr-10 5:15

Luc Pattyn

8-Apr-10 5:15

yes, you can send key strokes and mouse actions to any window you like, whether in your own app or another one. However may be tricky, and error prone; the user (assuming there is one) may well interfere with your automation (or vice versa), so I do not recommend it in general.

If you must, there is the SendKeys class; its SendWait() method is useful. What I have been doing for mouse automation mostly is based on Win32 functions such as SetCursorPos() and SendInput(), both in user32.dll

WARNING: localization changes the shortcut letters that can be used to steer menu's and buttons.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

How to unload mixed-mode MFC assembly loaded in AppDomain

catrill5-Apr-10 17:31

catrill

5-Apr-10 17:31

We have been bringing our old C++ code that uses MFC into the .NET world by compiling it into a mixed-mode assembly. We have found that when this assembly is loaded in an AppDomain e.g. by NUnit or by ASP .NET, the dll is not unloaded when the AppDomain is unloaded. The host application can load the dll many times, and may eventually run out of memory.

I have found that this is due to static data. If I make a simple mixed mode assembly with no static data, or with a static object with a default constructor, the dll is unloaded correctly. If the object has a non-trivial constructor, then the dll is not unloaded.

Even the simplest MFC dll has a static CWinApp derived object, so I don't think it would be possible to remove this kind of static data from our mixed-mode dll without a removing its dependency on MFC (a task that is too big to contemplate at the moment). Is there any other way to force the mixed-mode dll to be freed when the AppDomain is unloaded?

unable to call function in CLI/C++ dll from native C++, when linked Explicitly

Cherry_manju4-Apr-10 23:51

Cherry_manju

4-Apr-10 23:51

Hi,
I am able to call the funtion successfully, when linked the dll implicitly.
But when I am linking explicitly using LoadLibrary and GetProcAddress, GetProcAddress returning NULL value.
what mightbe the problem, I am using the same function name as I have used while implicit linking.

regards,
Charan

Re: unable to call function in CLI/C++ dll from native C++, when linked Explicitly

N a v a n e e t h5-Apr-10 15:44

N a v a n e e t h

5-Apr-10 15:44

Are you saying it works when you link statically? Have you exported the functions that are eligible to call?

Best wishes,
Navaneeth

global access to objects / instances

KlaasVersteeg31-Mar-10 2:31

31-Mar-10 2:31

I'm quite new to programming C++ and I ran into a problem. I'm working on a program in which some objects are being used by different functions, in separate files. I created the objects in a header file and can access them from a source file. However, I would like to have an instance of the object available for access from all of my functions. How can I create such objects / instances?

Any help is highly appreciated.

Richard MacCutchan31-Mar-10 2:46

Richard MacCutchan

31-Mar-10 2:46

I'm not sure I fully understand your question, but the usual way of doing this is to pass a reference to the object to each function that requires it. Making objects globally visible is generally less safe. For example:

int main()
{
    CType* object = new CType();
    // do other stuff

    // call a function, passng it reference to the object
    BOOL result = MyFunc(object);
    // etc
}
BOOL MyFunc(CType* anObject)
{
    // do other work
    // call next function passing the object pointer
    int rc = OtherStuff(anObject);

    // etc
}

txtspeak is the realm of 9 year old children, not developers. Christian Graus

KlaasVersteeg31-Mar-10 2:59

31-Mar-10 2:59

Thanks for the quick answer Richard!

I tried to do this, but the problem I ran into is the following:

I have a sourcefile "program.cpp" with header "program.h" in which my classes are defined. I want to pass an object from "program.cpp" to "function1.cpp", by:
double^ function1result = function1(CType^ object)

In function1 I should now write the function as:
double^ function1(CType^ object){}

When I do that, I get an "undeclared identifyer" error. When I include the "program.h" header where the class is defined I get a "type redefinition" error. So my question is how to pass these objects in a way that such errors are avoided.

Richard MacCutchan31-Mar-10 3:07

Richard MacCutchan

31-Mar-10 3:07

Arjen Tjallema wrote:
When I include the "program.h" header where the class is defined I get a "type redefinition" error.

This means you are defining the type (presumably CType) in more than one place in your source code. Without seeing more of your header and source file it's difficult to be more explicit.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

KlaasVersteeg31-Mar-10 3:25

31-Mar-10 3:25

Thanks again! I'll put some bits of my code here to clarify my question.

The "program.h" header contains a class clGlobals:

public ref class clGlobals
{
public:
	double^ airDensity;
	double^ waterDensity;
	double^ gravitation;
};

In my "program.cpp" source I create an instance, put some values in it and (try to) call function1:

clGlobals^ globals = gcnew clGlobals();
globals->airDensity = Convert::ToDouble(1.025);
globals->waterDensity = Convert::ToDouble(1025);
globals->gravitation = Convert::ToDouble(9.81);

double^ load = function1();

The "function1.h" header contains a declaration of the function:

double^ load(clGlobals^ global);

And the "function1.cpp" source contains the actual function:

double^ load(clGlobals^ global)
{
        // function stuff...
	return load;
}

I hope this clarifies my question.