Using IAsyncResult : IAsyncResult « Development « Visual C++ .NET

1. Visual C++ .NET
2. Development
3. IAsyncResult

Using IAsyncResult

 

#include "stdafx.h"
using namespace System;
using namespace System::Threading;

ref class MyClass{
public:
   property String^ Value;

   MyClass(String^ s) { Value = s; }
};

delegate void DoSearch(String^, MyClass^);

ref class Database{
   IAsyncResult^ result;
   MyClass^ m_r;
   public:
      Database(String^ s) { m_r = gcnew MyClass(s); }

   void Query(String^ queryString, MyClass^ r){
       r->Value = "New Value";
   }
   void InitiateQuery(String^ queryString){
      DoSearch^ qf = gcnew DoSearch(this, &Database::Query);
      Console::WriteLine(m_r->Value);
      result = qf->BeginInvoke(queryString, m_r,gcnew AsyncCallback(this, &Database::ProcessResult),qf);
   }

   bool IsQueryCompleted(){
      return result->IsCompleted;
   }

   void ProcessResult(IAsyncResult^ result)
   {
      DoSearch^ caller = (DoSearch^) result->AsyncState;
      caller->EndInvoke(result);
      Console::WriteLine(m_r->Value);
   }

};
int main(){
   Database doc("Old Value");
   doc.InitiateQuery("SELECT * FROM Employee ");

   while (! doc.IsQueryCompleted() ){
       Thread::Sleep(100);
   }
}

   
  

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