C++: DialogResult and namespaces confusion...

Question

Hi I'm working with C++ Express, I'm new to Windows Forms and the namespaces used but not to C++. I'm having difficulties with DialogResults:

The MSDN documentation gives examples like this:

System::Windows::Forms::DialogResult result;
result = MessageBox::Show( this, message, caption, buttons );
if ( result == ::DialogResult::Yes )

Yet when I compile I get the following errors (for the if line) :

error C3083: 'DialogResult': the symbol to the left of a '::' must be a type
error C2039: 'Yes' : is not a member of '`global namespace''
error C2065: 'Yes' : undeclared identifier

So I also try without the leading :: and get:

error C2039: 'Yes' : is not a member of 'System::Windows::Forms::Form::DialogResult'
see declaration of 'System::Windows::Forms::Form::DialogResult'
error C2065: 'Yes' : undeclared identifier

Finally I try with the whole namespace (is that the right terminology ?) and it compiles:

if (result == System::Windows::Forms::DialogResult::Yes )

Now I suspect I may be missing something, but I copied this code from the MSDN examples yet in is not working, can someone tell me what I ought to be doing ? and is there some documentation I should be reading on this ?

Answer 1

Hi there -

Make sure you have both the #using and the using namespace directives to ensure the compiler understands your references.

For example -

#using <System.DLL>
#using <System.Drawing.DLL>
#using <System.Windows.Forms.DLL>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;

Thanks,
April Reagan
Visual C++ Program Management

Answer 2

Hi, i was having the exact same problem, i implemented the #using directives as you described but makes no difference at all, still need to type in system::windows::forms::dialogresult::ok for it to compile, any other suggestions would be great.

Answer 3

i  meet  a similar problem

  
     if ( openFileDialog1->ShowDialog() ==DialogResult::OK )
      {
         if ( (myStream = openFileDialog1->OpenFile()) != nullptr )
         {
            // Insert code to read the stream here.
            myStream->Close();
         }
      }

there are  only  tow items can be  selected  after  DilogResrlt::  .  they  are   get()  and   set().

 

Answer 4

Just wasted a morning on this one -- anyone got a fix yet? Seems there's already confusion in the docs, I've seen two MS code snippets, one reading:

 if ( openFileDialog1->ShowDialog() == DialogResult::OK )

the other:

 if ( openFileDialog1->ShowDialog() == ::DialogResult::OK )

Seriously thinking of moving to another platform... max sympathy to fellow-sufferers

FM

Answer 5

April Reagan MSFT wrote:

Hi there - Make sure you have both the #using and the using namespace directives to ensure the compiler understands your references. For example - #using <System.DLL> #using <System.Drawing.DLL> #using <System.Windows.Forms.DLL> using namespace System; using namespace System::Drawing; using namespace System::Windows::Forms;

Thanks April Reagan ,your suggestion solves my little problem.

and my problem was (Compiler Error C3083): the compiler couldn't recognize this:

System::Windows::Forms::MessageBox::Show("disposed");

But after writing  #using <System.Windows.Forms.DLL> in my code, Wow, this solves the problem and my happy life back again.

Thanks April Reagan

Answer 6

#using <System.DLL>
#using <System.Drawing.DLL>
#using <System.Windows.Forms.DLL>

Those did not help me. Same compile errors. But when I included the same sample code  into a MDI form application. The compile error went away. Very strange.


---
Free stuff is not really free, if it wastes your time.

Answer 7

I have the same exact issue and placing the #using directives doesn't work.

Still get these three errors:

Error    1    error C3083: 'DialogResult': the symbol to the left of a '::' must be a type   
Error    2    error C2039: 'OK' : is not a member of '`global namespace''   
Error    3    error C2065: 'OK' : undeclared identifier


Writing the entire System::Windows::Form:ialogResult:K compiles.

I'm have another issue, when I run the program the OpenFileDialog opens again after selecting a file.

This is strange, ShowDialog() returns a bool yet, what does OpenFileDialog1->ShowDialog() return? 

The dialog result should just be a member of the OpenFileDialog class, then checking a field in the data structure/class would be very easy.  But I'm not even sure what the is :ialogResult:K is doing, how does it get the pointer to the correct dialog box?

Is C++ dead?  has everyone just gone to C#?

This thread has gone 15 months unsolved!

Answer 8

in visual c++ express try

Code Snippet

System::Windows::Forms::DialogResult::OK instead of DialogResult::OK

it worked for me

Answer 9

great System::Windows::Forms:ialogResult:K worked instead of DialogResult:K i just don't get why as i have
using namespace System::Windows::Forms;
in my sourcecode, shouldn't that handle it?

but thanks a lot.

Answer 10

The  :: in front of DialogResult means DialogResult is a global identifier. The problem occurs when your using namespace declarations are inside of your local namespace.

The solution is to move those statements outside of and before your form application namespace.

*** THIS IS A PROBLEM ***

namespace myApp {

using namespace System;

using namespace System::Windows::Forms;

if ( result == :ialogResult::Yes ){
}

}

************************************

*** THIS FIXES THE PROBLEM ***


using namespace System;
using namespace System::Windows::Forms;

namespace myApp {

if ( result == :ialogResult::Yes ){
}

}

*****************************

Answer 11

Joe58,

Thanks!!

Solved the problem for me.

Clay L

Answer 12

thanks ,your imformation is right.
move the internal namespace out of your local namespace, it works.

---

MSN:[e-mail]

Answer 13

Thanks that's the simplest solution

Answer 14

short

private: System::Void Vaciar_Click(System::Object^  sender, System::EventArgs^  e) {
  short Confirmacion;
  Confirmacion = Convert::ToInt16(MessageBox::Show("DeleteList","Eliminar",MessageBoxButtons::YesNo,MessageBoxIcon::Question));
       if((Confirmacion.CompareTo(Convert::ToInt1(System::Windows::Forms::DialogResult::Yes)))    ==0){
          Lista->Items->Clear();
         NArticulos->Text=Convert::ToString(Lista->Items->Count);
   
    }
}