BUG: IntelliSense Limitations with C++ Classes

View products that this article applies to.

This article was previously published under Q190968

SYMPTOMS

This article discusses some of the limitations of IntelliSense when working with classes. The following problems are addressed:

Class constructors do not activate Parameter Info.
Private members display in Members list for an object outside of the class definition.
IntelliSense may not recognize standard Win32 data types in member functions when default parameters are used.
IntelliSense does not recognize the member functions of a few new MFC classes, such as CIPAddressCtrl, CMonthCalCtrl, CRebar, and CRebarCtrl.
IntelliSense may not display the member list of a class in the constructor of a derived class if its virtual base class member is used inside the derived class constructor.

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Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

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MORE INFORMATION

The following is a code sample that illustrates the limitations described in this article. This sample should be placed into a header file:

   // 
   // Test.h : IntelliSense Class Limitations
   // 

   //void IntelliSenseFix(DWORD,UINT);

   class CIntelliSense
   {
   public :
      CIntelliSense(int n=5) { Num = n; }
      void Win32Types(DWORD dw=10, UINT ui=6) {}
      void MFCProblem()
      {
         CMonthCalCtrl calCtrl;
      }

   private :
      void PrivateFunction() {}
      int Num;
   }

Create a Visual C++ MFC project, and include the header file above into a source file.

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Class Constructors Do Not Activate Parameter Info

Type the following line of code into the source file:

CIntelliSense CIs(

Notice that no Parameter Info appears for the optional parameter "n" in the class constructor.

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Private Members Display in Members List Outside the Class Definition

Type the following lines of code into the source file:

   CIntelliSense CIs;
   CIs.

The Members list for the CIntelliSense class should appear after typing the period. Notice that it contains the PrivateFunction member function and the Num member variable.

Although these functions and variables appear in the Members list, they will generate a compiler error C2248 if used. Private member variables and functions can not be used outside of the class in which they are defined.

IntelliSense May Not Recognize Standard Win32 Data Types in Member

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Functions When Default Parameters Are Used

Type the following lines of code into the source file:

   CIntelliSense CIs;
   CIs.Win32Types(

Notice that only the first DWORD parameter appears in the Parameter Info for this function. IntelliSense does not provide Parameter Info for the second parameter of this function.

When an unknown data type is used in a member function parameter list, IntelliSense stops parsing the function at that point. At times, IntelliSense does not recognize Win32 data types as valid data types when used in member functions. This is related to the use of default parameters, and it causes Parameter Info and Type Info to generate a truncated list of function parameters. The only way to avoid this problem is to use the data type outside of a default parameter list before it is used in the member function. This has to occur in the same file that contains the class definition. The following is a workaround:

Identify all of the data types that are having this problem.
Create a global function prototype above the class where the problem occurs.
Place each of the data types that IntelliSense doesn't recognize in the function's parameter list.

In the sample code, remove the comments from the global IntelliSenseFix prototype function. The complete Parameter Info and Type Info now appears for the Win32Types function.

IntelliSense Does Not Recognize the Member Functions of a Few New MFC

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Classes, such as CIPAddressCtrl, CMonthCalCtrl, CRebar, and CRebarCtrl

In the CIntelliSense::MFCProblem function, enter a new line after the instantiation of the CMonthCalCtrl object. Insert the following code:

calCtrl.

The Members list will appear, but it does not include the member functions for CmonthCalCtrl; however, it does include the members for the CWnd class.

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REFERENCES

For additional information, please see the following article in the Microsoft Knowledge Base:

153284 (http://support.microsoft.com/kb/153284/EN-US/ ) Limitations of IntelliSense in Visual C++ 6.0

"About Automatic Statement Completion;" Visual C++ Documentation, Using Visual C++, Visual C++ Users Guide, Text Editor, Overview: Text Editor, About Automatic Statement Completion.

"Automatically Completing Statements;" Visual C++ Documentation, Using Visual C++, Visual C++ Users Guide, Text Editor, How do I ... Topics: Text Editor, Automatically completing Statements.

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