Managed C++/CLI

Re: Load from String Table

12-Mar-11 3:34

fzerd wrote:
Any idea ?

Not really, I have not seen this problem. I can only suggest you check all your settings in your forms and start up code to ensure nothing is maximising the windows.

I must get a clever new signature for 2011.

Load from String Table

pix_programmer8-Mar-11 20:59

pix_programmer

8-Mar-11 20:59

Hi!
I've to get the string from the String Table. I used the following code:

wchar_t myDocs[1024];
::LoadString(NULL,IDS_USERNAME_CH,myDocs,1024);

It shows the following error:
error C2065: 'IDS_USERNAME_CH' : undeclared identifier

I've to read the string(with ID IDS_USERNAME_CH) from the string Table and set the Text to a label. How to do this in C++/CLI?

Richard MacCutchan8-Mar-11 22:45

std::string to System::String conversion

8-Mar-11 22:45

That message seems fairly clear, check where have you defined IDS_USERNAME_CH and make sure it is included in the module you are trying to compile.

I must get a clever new signature for 2011.

piul8-Mar-11 6:30

piul

8-Mar-11 6:30

Hi,

I have

System::String ^ St = gcnew System::String("Hey ho!");
//...
std::string str("standard");

St = str;  //This line won't work, but it's what I'd like to achieve

The only way I can make it work is by doing gcnew again St = gcnew System::String(str.c_str()); but I'm guessing this is not the right way. All the examples I have found tell how to do this when creating a new instance of System::String but none how to do it with an existing one.

Richard MacCutchan8-Mar-11 6:45

8-Mar-11 6:45

System::String() has no constructor that accepts a std::string Try this:

St = str->c_str();

I must get a clever new signature for 2011.

piul8-Mar-11 6:51

piul

8-Mar-11 6:51

Tried it, no good.

error C2664: 'void System::Windows::Forms::Control::Text::set(System::String ^)' : cannot convert parameter 1 from 'const char *' to 'System::String ^'	<br />

Richard MacCutchan8-Mar-11 8:14

8-Mar-11 8:14

Sorry, I guess there is no simple way to do this other than :

St = gcnew System::String(str.c_str());

I must get a clever new signature for 2011.

piul9-Mar-11 21:48

piul

9-Mar-11 21:48

Fair enough. That's what I'd done, but... am I not re-allocating memory without freeing it first?? (I have to do it for a dozen of strings!)

Richard MacCutchan9-Mar-11 22:55

9-Mar-11 22:55

piul wrote:
am I not re-allocating memory without freeing it first?

It depends on the actual structure of your code. I think a more pertinent question would be: why are you using both std::string and System::String when you only really need one of them, probably the latter. For example code such as:

std::string str("Some string");
System::String ^ st = gcnew(str.c_str());

serves no real purpose, in that the std::string is totally redundant.

I must get a clever new signature for 2011.

Displaying Chinese Characters

anti.AS11-Mar-11 0:02

anti.AS

11-Mar-11 0:02

what about

St = gcnew String(str);

using namespace System::Runtime::InteropServices;
...
...
St = Marshal::PtrToStringAnsi((IntPtr)str);

T.RATHA KRISHNAN7-Mar-11 2:33

T.RATHA KRISHNAN

7-Mar-11 2:33

Hi!
I've set the Text to my label from an XML file. I need to set a chinese word to a label. Here is my XML file contents:

 <?xml version="1.0" encoding="UTF-8" ?> 
<Remember>游戏目的是使两手牌的点数越比庄家接近</Remember>

The chinese word is for test purpose only(may not be meaningful word). Here is my code for reading this tag and setting the text to a label.

XmlDocument ^ Config = gcnew XmlDocument;

if(System::IO::File::Exists("Config.xml"))
{
    Config->Load("Config.xml");
}
XPathNavigator ^ nav = Config->CreateNavigator();
XPathNodeIterator ^ iter;
            iter = nav->Select("download/Remember");
while(iter->MoveNext())
{
    System::String ^ ConfigText = iter->Current->Value;
    ConfigText->Trim();
}
System::Runtime::InteropServices::Marshal::StringToHGlobalUni(ConfigText);
m_pRemember->Text = ConfigText;

While I execute the program only boxes are displayed in place of the chinese characters. If I open the XML file in a browser, the chinese characters are displayed. What else to do to display the chinese language?

Re: Displaying Chinese Characters

John Schroedl7-Mar-11 5:20

Setting Access Control to a file. [modified]

7-Mar-11 5:20

Where are you displaying the text and seeing the boxes? To the console? To a TextBox or TextBlock?

If they are going to the console, then it probably makes sense that you'd see boxes as the console font is probably not set properly to a font with those characters. Use the system menu to change the font to a unicode font and try again if that's the case.

If it's to a textbox, again, check the typeface you're using. The browser is probably dynamically loading the font glyphs it needs and painting with those.

John

pix_programmer3-Mar-11 20:47

pix_programmer

3-Mar-11 20:47

Hi!
How to set Full Control & Write Unlock to a file from C++/CLI? The reason why I want this is:
I'm creating a log in form. While clicking a button, I'm writing the log in information to a file(to implement "Remember Me" functionality). While creating installer for this application, this works fine under Win XP. But did not work with Windows 7. There I've to manually set Full Control to the file. Users of my app won't like this. I used the following code to set Access control:

path = L"RememberMe.ini";	System::IO::File::SetAccessControl(path,System::Security::AccessControl::FileSecurity::WriteUnlock());

But this results in the following error:

error C3767: 'System::Security::AccessControl::ObjectSecurity::WriteUnlock': candidate function(s) not accessible

How to set access control from C++/CLI? or Can any one suggest an alternative solution to my problem? I'm using Visual Studio 2008 Deployment Project to write setup file.

modified on Friday, March 4, 2011 1:59 AM

Re: Setting Access Control to a file.

N a v a n e e t h4-Mar-11 6:25

N a v a n e e t h

4-Mar-11 6:25

pix_programmer wrote:
error C3767: 'System::Security::AccessControl::ObjectSecurity::WriteUnlock': candidate function(s) not accessible

You are trying to access a protected method. WriteUnlock() is a protected method and won't be accessible from outside the class.

pix_programmer wrote:
While creating installer for this application, this works fine under Win XP. But did not work with Windows 7. There I've to manually set Full Control to the file.

From Vista onwards, you need to utilize the program data folders to write information like this. You will have full write access to these folders.

pix_programmer wrote:
How to set access control from C++/CLI

Look at the MSDN documentation[^] for SetAccessControl() method.

Smile | :)

Best wishes,
Navaneeth

User Control

Milton N3-Mar-11 1:18

Milton N

3-Mar-11 1:18

Hi all,
I'm working on a user control which is basicly a customized edit control (HexEditBox).
It has a context menu which is activated by the right mouse click, as per normal.
All is working fine with the control, but has a visual aspect that I'm not happy with.
When the context menu is activated the caret is hidden from the control.
For most of the menu items this is irrelevant, but for the paste option the user looses
visual indication where the paste will occur.
It is anyway possible the prevent the context menu from hiding the controls caret?
Thanks in advance .. Milton

Re: User Control

amit_soni3-Mar-11 1:59

amit_soni

3-Mar-11 1:59

Passing arrays betwen C++ and C#

jordabi2-Mar-11 5:31

2-Mar-11 5:31

I have a C# method declared as:

public static bool MethodName(double [] d1,....)

and am try to call it from a C++ mixed mode method. I have tried to to so as follows:

array<double ^,="" 1=""> ^d = gcnew array<double ^,="" 1="">(2);
d[0] = gcnew double
d[1] = gcnew double
d[0] = 1.0;
d[1] = 2.0;

classname::MethodName(d);

I get a compler error saying cannot convert param 1 from cli::array<type, dimmension=""> ^ to cli::array<Type, dimmension> ^

Does anyone have any ideas on how to correctly pass an arry from C++ to c#?

John Schroedl2-Mar-11 5:53

2-Mar-11 5:53

The array does not indicate the type of object in the array. So, I would allocate it like this:

array<double>^ d = gcnew array<double>(2);

d[0] = 1.0;
d[1] = 2.0;

MethodTakingDoubleArray(d);

John

jordabi2-Mar-11 6:01

2-Mar-11 6:01

Thanks. I actually just figured it out myself also. Do you by any chance know how to pass a double from C++ to C# as an out parameter?

John Schroedl2-Mar-11 6:05

2-Mar-11 6:05

Sure, that should be no problem. I just tried this.

C++/CLI side:

double val = 1.0;
CSharpObj->ChangeInCSharp(val);
Debug::WriteLine(val);

C# side:

public void ChangeInCSharp(out double changeme)
{
   changeme = 4.0;
}

John

jordabi2-Mar-11 6:25

2-Mar-11 6:25

Thank you. Now, can you explain why that works to me? I am a very seasoned native C++ and C# developer, but am pretty green to the CLI stuff. an out parameter would normally be passed by reference, but the way that this is being called seems to be by value.

John Schroedl2-Mar-11 7:47

2-Mar-11 7:47

It's all in the metadata of the method signature written by the C# compiler. When C++/CLI compiler resolves the call, it sees the IL Metadata indicating that the parameter is 'out'. So, the C++/CLI compiler knows to generate calling code with the value passed by reference. I haven't looked at the generated IL but it's also possible that the double is boxed when passed as an out parameter.

John

jordabi2-Mar-11 7:52

2-Mar-11 7:52

Thank you. I love "automagic" code.

John Schroedl2-Mar-11 8:06