For each with IDictionary

For each with IDictionary

• Sridhar Paladugu

  Just for other folks on the forums, Here is a link to the bug: http://lab.msdn.microsoft.com/ProductFeedback/viewFeedback.aspx feedbackid=7dabbf4b-cc28-4cb3-b0cf-14100a949ce6

  Thanks,

  Ayman Shoukry

  VC++ Team

  
  
  

• ssmile73

  MsFit, could you log a bug at http://lab.msdn.microsoft.com/productfeedback/default.aspx so that the owners take a look straight ahead.

  Thanks,

  Ayman Shoukry

  VC++ Tean

  
  
  

• tricky_richy

  Can someone at microsoft comment

  It looks like for each is either unavailable or unusable in /clr:oldSyntax (which means there is a documentation error or a bug in the Microsoft C++ compiler). I've tried using for each in /clr:oldSyntax

  __gc class A {
  public:

    static void B(void)
    {

      int NumArray __gc[] = new int __gc[5];

      for each(int q in NumArray)
      {
        System::Console::WriteLine(q);
      }

    }

  };

  and I get the following errors

  .\Dictionary.cpp(8) : error C3083: 'cli': the symbol to the left of a '::' must be a type
  .\Dictionary.cpp(8) : error C2039: 'safe_cast' : is not a member of '`global namespace''
  .\Dictionary.cpp(8) : error C2065: 'safe_cast' : undeclared identifier
  .\Dictionary.cpp(8) : error C2062: type 'int' unexpected

  The first error is particularly interesting. It indicates it is trying to use the namespace cli (only available in C++/CLI) from within old managed C++. The equivalent class in C++/CLI:

  ref class A {
  public:
    static void B(void)
    {

      cli::array<int> ^NumArray = gcnew cli::array<int>(5);
      for each(int q in NumArray)
      {
        System::Console::WriteLine(q);
      }
    }

  };

  Compiles fine. This indicates that for each is not supported under managed C++ (why aren't you saying so in MSDN, and why doesn't the compiler give a clearer error )

  MsFiT...

  you should make it a priority to transition to C++/CLI if you can. The for each construct DOES work under C++/CLI. If that is not an option, try using the TryGetValue method (sorry, I'm not familiar with how to box/unbox values, So I'm going to cheat and use a slightly different IDictionary):

  System::Collections::Generic::IDictionary<int, int> *idict;

  for(int i = 0; i < idict->Count; ++i)
  {

    int ValRes = 0;
    idict->TryGetValue(i, &ValRes);
    System::Console::Write(ValRes);

  }

   

  
  
  

• happyt

  But these variants don't work too:

  Collections::Generic::IDictionary<String*,int> * mapLetters;
  for each(Collections::Generic::KeyValuePair<String*,int>*& q in mapLetters){}

  
  
  

• CyberDogg

  Couldn't you help me to write a line of code which will use for-each construct with an IDictionary

  
  
  

• Diesel31

  MsFiT wrote:

  I've got such code: Collections::Generic::IDictionary<String*,int> *mapLetters; for each(Collections::Generic::KeyValuePair<String,int>*q in mapLetters){ myFunction(); } And the for-each element does not work. I've got an error: error C3285: for each statement cannot operate on variables of type 'System::Collections::Generic::IDictionary<TKey,TValue> __gc *' But in official site of Microsoft they wrote that for-each must work fine. There's the note there: -- The foreach statement of the C# language (For Each in Visual Basic, for each in C++) requires the type of each element in the collection. Since each element of the IDictionary is a key/value pair, the element type is not the type of the key or the type of the value. Instead, the element type is KeyValuePair. For example: C++: for each (KeyValuePair<int, String^> kvp in myDictionary) {...} -- Here's the link: http://msdn2.microsoft.com/en-us/library/s4ys34ea(VS.80).aspx Something is wrong. How can I use for-each with IDictionary-element

  Although he wrote it specifically for C++/CLI, nish has already answered this question: http://blog.voidnish.com/ p=99.

  To find out how to pass-by-reference types in /clr:oldSyntax, see the last question in http://msdn.microsoft.com/msdnmag/issues/06/01/CAtWork/default.aspx.

  If the compiler still complains, take a close look at the comments made in nish's blog posting.

  
  
  
• For each with IDictionary