Hi everyone!

I would like to know how to show my Form21 from a click on a button in Form1 I used this code here:

#include "Form21.h"
///
Form21 ^maForm2 = gcnew Form21();
maForm21->Show();

I do not know why it does not work yet I found it in FAQC + + / CLR

it shows me these errors:

1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(526): error C2065: 'Form21' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(526): error C2065: 'maForm2' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(526): error C2061: erreur de syntaxe : identificateur 'Form21'
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(527): error C2065: 'maForm2' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(527): error C2227: la partie gauche de '->Show' doit pointer vers un type class/struct/union/générique
1>          le type est ''unknown-type''
========== Génération : 0 a réussi, 1 a échoué, 1 mis à jour, 0 a été ignoré 

Thank you so much in advance

@ ddanbe: this is Form1.h

#pragma once
#include "tinyxml.h"
#include <string>
#include <vector>
#include <iostream>
#include "ConnectedComponentSearch1.h"
#include "ReadTestersResourcesXML.h"
#include "ReadTestersResourcesXML.h"
#include "ReadXMLTestersResources.h"
#include "ConnectedComponent.h"
#include "ReadEnvironmentXML1.h"
#include "crerxmlfichier1.h"
#include <sstream>
#include "msclr\marshal_cppstd.h"
#include"TestComponentsGainsVsNodesPlacement.h"
#include "Form21.h"
using namespace std;
namespace interfaceProject {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;
    using namespace System::IO;
    using namespace System::Runtime::InteropServices;

    /// <summary>
    /// Description résumée de Form1
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    public:
         Form1()
      : Form()
   {

      //This call is required by the Windows Form Designer.
      InitializeComponent();

      //Add any initialization after the InitializeComponent() call
   }

    protected:
        /// <summary>
        /// Nettoyage des ressources utilisées.
        /// </summary>
        ~Form1()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::Label^  L_NodesProvidedResources;
    protected: 
    private: System::Windows::Forms::Label^  L_TestersRequiredResources;
    private: System::Windows::Forms::DataGridView^  dataGridView1;
    private: System::Windows::Forms::DataGridView^  dataGridView2;
    private: System::Windows::Forms::Panel^  P_panelLodGain;

    private: System::Windows::Forms::Button^  B_LoadNode;
    private: System::Windows::Forms::Button^  B_LoadTest;
    private: System::Windows::Forms::Label^  l_gain;
    private: System::Windows::Forms::Button^  B_Load_Gain_Matrix;

    private: System::Windows::Forms::DataGridView^  dataGridView3;
    private: System::Windows::Forms::Button^  B_GecodeSolver;
    private: System::Windows::Forms::Button^  B_ShowResults;
    private: System::Windows::Forms::Button^  B_GenerateTestPlan;
    private: System::Windows::Forms::Button^  B_Quit;







    private:
        /// <summary>
        /// Variable nécessaire au concepteur.
        /// </summary>
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
        /// <summary>
        /// Méthode requise pour la prise en charge du concepteur - ne modifiez pas
        /// le contenu de cette méthode avec l'éditeur de code.
        /// </summary>
        void InitializeComponent(void)
        {
            this->L_NodesProvidedResources = (gcnew System::Windows::Forms::Label());
            this->L_TestersRequiredResources = (gcnew System::Windows::Forms::Label());
            this->dataGridView1 = (gcnew System::Windows::Forms::DataGridView());
            this->dataGridView2 = (gcnew System::Windows::Forms::DataGridView());
            this->P_panelLodGain = (gcnew System::Windows::Forms::Panel());
            this->l_gain = (gcnew System::Windows::Forms::Label());
            this->B_Load_Gain_Matrix = (gcnew System::Windows::Forms::Button());
            this->dataGridView3 = (gcnew System::Windows::Forms::DataGridView());
            this->B_LoadNode = (gcnew System::Windows::Forms::Button());
            this->B_LoadTest = (gcnew System::Windows::Forms::Button());
            this->B_GecodeSolver = (gcnew System::Windows::Forms::Button());
            this->B_ShowResults = (gcnew System::Windows::Forms::Button());
            this->B_GenerateTestPlan = (gcnew System::Windows::Forms::Button());
            this->B_Quit = (gcnew System::Windows::Forms::Button());
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView1))->BeginInit();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView2))->BeginInit();
            this->P_panelLodGain->SuspendLayout();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView3))->BeginInit();
            this->SuspendLayout();
            // 
            // L_NodesProvidedResources
            // 
            this->L_NodesProvidedResources->AutoSize = true;
            this->L_NodesProvidedResources->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, static_cast<System::Drawing::FontStyle>((System::Drawing::FontStyle::Bold | System::Drawing::FontStyle::Italic)), 
                System::Drawing::GraphicsUnit::Point, static_cast<System::Byte>(0)));
            this->L_NodesProvidedResources->Location = System::Drawing::Point(61, 35);
            this->L_NodesProvidedResources->Name = L"L_NodesProvidedResources";
            this->L_NodesProvidedResources->Size = System::Drawing::Size(184, 18);
            this->L_NodesProvidedResources->TabIndex = 0;
            this->L_NodesProvidedResources->Text = L"Nodes Provided Resources: ";
            // 
            // L_TestersRequiredResources
            // 
            this->L_TestersRequiredResources->AutoSize = true;
            this->L_TestersRequiredResources->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, static_cast<System::Drawing::FontStyle>((System::Drawing::FontStyle::Bold | System::Drawing::FontStyle::Italic)), 
                System::Drawing::GraphicsUnit::Point, static_cast<System::Byte>(0)));
            this->L_TestersRequiredResources->Location = System::Drawing::Point(425, 35);
            this->L_TestersRequiredResources->Name = L"L_TestersRequiredResources";
            this->L_TestersRequiredResources->Size = System::Drawing::Size(187, 18);
            this->L_TestersRequiredResources->TabIndex = 1;
            this->L_TestersRequiredResources->Text = L"Testers Required Resources:";
            this->L_TestersRequiredResources->Click += gcnew System::EventHandler(this, &Form1::L_TestersRequiredResources_Click);
            // 
            // dataGridView1
            // 
            this->dataGridView1->ColumnHeadersHeightSizeMode = System::Windows::Forms::DataGridViewColumnHeadersHeightSizeMode::AutoSize;
            this->dataGridView1->Location = System::Drawing::Point(33, 65);
            this->dataGridView1->Name = L"dataGridView1";
            this->dataGridView1->Size = System::Drawing::Size(230, 123);
            this->dataGridView1->TabIndex = 2;
            this->dataGridView1->CellContentClick += gcnew System::Windows::Forms::DataGridViewCellEventHandler(this, &Form1::dataGridView1_CellContentClick);
            // 
            // dataGridView2
            // 
            this->dataGridView2->ColumnHeadersHeightSizeMode = System::Windows::Forms::DataGridViewColumnHeadersHeightSizeMode::AutoSize;
            this->dataGridView2->Location = System::Drawing::Point(410, 65);
            this->dataGridView2->Name = L"dataGridView2";
            this->dataGridView2->Size = System::Drawing::Size(240, 123);
            this->dataGridView2->TabIndex = 3;
            this->dataGridView2->CellContentClick += gcnew System::Windows::Forms::DataGridViewCellEventHandler(this, &Form1::dataGridView2_CellContentClick);
            // 
            // P_panelLodGain
            // 
            this->P_panelLodGain->Controls->Add(this->l_gain);
            this->P_panelLodGain->Controls->Add(this->B_Load_Gain_Matrix);
            this->P_panelLodGain->Controls->Add(this->dataGridView3);
            this->P_panelLodGain->Location = System::Drawing::Point(33, 258);
            this->P_panelLodGain->Name = L"P_panelLodGain";
            this->P_panelLodGain->Size = System::Drawing::Size(617, 123);
            this->P_panelLodGain->TabIndex = 4;
            // 
            // l_gain
            // 
            this->l_gain->AutoSize = true;
            this->l_gain->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, static_cast<System::Drawing::FontStyle>((System::Drawing::FontStyle::Bold | System::Drawing::FontStyle::Italic)), 
                System::Drawing::GraphicsUnit::Point, static_cast<System::Byte>(0)));
            this->l_gain->Location = System::Drawing::Point(198, 21);
            this->l_gain->Name = L"l_gain";
            this->l_gain->Size = System::Drawing::Size(74, 18);
            this->l_gain->TabIndex = 2;
            this->l_gain->Text = L"Gain (i,j)=";
            // 
            // B_Load_Gain_Matrix
            // 
            this->B_Load_Gain_Matrix->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_Load_Gain_Matrix->Location = System::Drawing::Point(155, 57);
            this->B_Load_Gain_Matrix->Name = L"B_Load_Gain_Matrix";
            this->B_Load_Gain_Matrix->Size = System::Drawing::Size(157, 23);
            this->B_Load_Gain_Matrix->TabIndex = 1;
            this->B_Load_Gain_Matrix->Text = L"Load_Gain_Matrix";
            this->B_Load_Gain_Matrix->UseVisualStyleBackColor = true;
            this->B_Load_Gain_Matrix->Click += gcnew System::EventHandler(this, &Form1::B_Load_Gain_Matrix_Click);
            // 
            // dataGridView3
            // 
            this->dataGridView3->ColumnHeadersHeightSizeMode = System::Windows::Forms::DataGridViewColumnHeadersHeightSizeMode::AutoSize;
            this->dataGridView3->Location = System::Drawing::Point(374, 3);
            this->dataGridView3->Name = L"dataGridView3";
            this->dataGridView3->Size = System::Drawing::Size(240, 117);
            this->dataGridView3->TabIndex = 0;
            this->dataGridView3->CellContentClick += gcnew System::Windows::Forms::DataGridViewCellEventHandler(this, &Form1::dataGridView3_CellContentClick);
            // 
            // B_LoadNode
            // 
            this->B_LoadNode->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_LoadNode->Location = System::Drawing::Point(105, 212);
            this->B_LoadNode->Name = L"B_LoadNode";
            this->B_LoadNode->Size = System::Drawing::Size(75, 23);
            this->B_LoadNode->TabIndex = 5;
            this->B_LoadNode->Text = L"Load";
            this->B_LoadNode->UseVisualStyleBackColor = true;
            this->B_LoadNode->Click += gcnew System::EventHandler(this, &Form1::B_LoadNode_Click);
            // 
            // B_LoadTest
            // 
            this->B_LoadTest->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_LoadTest->Location = System::Drawing::Point(497, 212);
            this->B_LoadTest->Name = L"B_LoadTest";
            this->B_LoadTest->Size = System::Drawing::Size(75, 23);
            this->B_LoadTest->TabIndex = 6;
            this->B_LoadTest->Text = L"Load";
            this->B_LoadTest->UseVisualStyleBackColor = true;
            this->B_LoadTest->Click += gcnew System::EventHandler(this, &Form1::B_LoadTest_Click);
            // 
            // B_GecodeSolver
            // 
            this->B_GecodeSolver->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_GecodeSolver->Location = System::Drawing::Point(54, 409);
            this->B_GecodeSolver->Name = L"B_GecodeSolver";
            this->B_GecodeSolver->Size = System::Drawing::Size(108, 23);
            this->B_GecodeSolver->TabIndex = 7;
            this->B_GecodeSolver->Text = L"Gecode Solver";
            this->B_GecodeSolver->UseVisualStyleBackColor = true;
            this->B_GecodeSolver->Click += gcnew System::EventHandler(this, &Form1::B_GecodeSolver_Click);
            // 
            // B_ShowResults
            // 
            this->B_ShowResults->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_ShowResults->Location = System::Drawing::Point(198, 409);
            this->B_ShowResults->Name = L"B_ShowResults";
            this->B_ShowResults->Size = System::Drawing::Size(107, 23);
            this->B_ShowResults->TabIndex = 8;
            this->B_ShowResults->Text = L"Show Results";
            this->B_ShowResults->UseVisualStyleBackColor = true;
            this->B_ShowResults->Click += gcnew System::EventHandler(this, &Form1::B_ShowResults_Click);
            // 
            // B_GenerateTestPlan
            // 
            this->B_GenerateTestPlan->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_GenerateTestPlan->Location = System::Drawing::Point(348, 409);
            this->B_GenerateTestPlan->Name = L"B_GenerateTestPlan";
            this->B_GenerateTestPlan->Size = System::Drawing::Size(142, 23);
            this->B_GenerateTestPlan->TabIndex = 9;
            this->B_GenerateTestPlan->Text = L"Generate Test Plan";
            this->B_GenerateTestPlan->UseVisualStyleBackColor = true;
            this->B_GenerateTestPlan->Click += gcnew System::EventHandler(this, &Form1::B_GenerateTestPlan_Click);
            // 
            // B_Quit
            // 
            this->B_Quit->Font = (gcnew System::Drawing::Font(L"Times New Roman", 11.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point, 
                static_cast<System::Byte>(0)));
            this->B_Quit->Location = System::Drawing::Point(537, 409);
            this->B_Quit->Name = L"B_Quit";
            this->B_Quit->Size = System::Drawing::Size(75, 23);
            this->B_Quit->TabIndex = 10;
            this->B_Quit->Text = L"Quit";
            this->B_Quit->UseVisualStyleBackColor = true;
            this->B_Quit->Click += gcnew System::EventHandler(this, &Form1::B_Quit_Click);
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(679, 455);
            this->Controls->Add(this->B_Quit);
            this->Controls->Add(this->B_GenerateTestPlan);
            this->Controls->Add(this->B_ShowResults);
            this->Controls->Add(this->B_GecodeSolver);
            this->Controls->Add(this->B_LoadTest);
            this->Controls->Add(this->B_LoadNode);
            this->Controls->Add(this->P_panelLodGain);
            this->Controls->Add(this->dataGridView2);
            this->Controls->Add(this->dataGridView1);
            this->Controls->Add(this->L_TestersRequiredResources);
            this->Controls->Add(this->L_NodesProvidedResources);
            this->Name = L"Form1";
            this->Text = L"Gecode";
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView1))->EndInit();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView2))->EndInit();
            this->P_panelLodGain->ResumeLayout(false);
            this->P_panelLodGain->PerformLayout();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView3))->EndInit();
            this->ResumeLayout(false);
            this->PerformLayout();

        }


#pragma endregion
        //this->StartPosition = FormStartPosition::CenterScreen;
    private: System::Void L_TestersRequiredResources_Click(System::Object^  sender, System::EventArgs^  e) {
             }
    private: System::Void dataGridView1_CellContentClick(System::Object^  sender, System::Windows::Forms::DataGridViewCellEventArgs^  e) {
                 dataGridView1->AutoResizeColumnHeadersHeight();

      // Resize all the row heights to fit the contents of all non-header cells.
     dataGridView1->AutoResizeRows(
            DataGridViewAutoSizeRowsMode::AllCellsExceptHeaders);
         // Set the column header names.


             }
    private: System::Void B_LoadNode_Click(System::Object^  sender, System::EventArgs^  e) {
 dataGridView1->ColumnCount = 4;
      dataGridView1->ColumnHeadersVisible = true;

      // Set the column header style.
      DataGridViewCellStyle ^ columnHeaderStyle = gcnew DataGridViewCellStyle;
      columnHeaderStyle->BackColor = Color::Aqua;
      columnHeaderStyle->Font = gcnew System::Drawing::Font( "Verdana",10,FontStyle::Bold );
      dataGridView1->ColumnHeadersDefaultCellStyle = columnHeaderStyle;

      // Set the column header names.
      dataGridView1->Columns[ 0 ]->Name = "";
      dataGridView1->Columns[ 1 ]->Name = "RAM";
      dataGridView1->Columns[ 2 ]->Name = "CPU";
      dataGridView1->Columns[ 3 ]->Name = "BAT";

      // Populate the rows.

    //  Console::WriteLine(f);
        ReadEnvironmentXML1 reader;
    //ReadTestersResourcesXML reader1;
    int size=reader.lire_size();
    vector<string> myNodes= reader.lire_Nodes();
    vector<vector<int>> edgs=reader.lire_Links();
    vector<int> capacitRam= reader.lire_RAM();
    vector<int> capacitBat = reader.lire_BAT( ) ;
    vector<int> capacitCPU= reader.lire_CPU();
    vector<vector<int>>  lnk_val = reader.lire_Links_val();
    vector<int> maxp= reader.lire_MaxP();

    while(!myNodes.empty())
    {
          int j =0;
        string f=myNodes[j];
      String^ Cell0= gcnew String(f.c_str());
        myNodes.erase( myNodes.begin());

       int Number=capacitRam[j];
       string g = static_cast<ostringstream*>( &(ostringstream() << Number) )->str();
       String^ Cell1= gcnew String(g.c_str());
       capacitRam.erase(capacitRam.begin());

        int Number1=capacitCPU[j];
      string h = static_cast<ostringstream*>( &(ostringstream() << Number1) )->str();
       String^ Cell2= gcnew String(h.c_str());
       capacitCPU.erase(capacitCPU.begin());

      int Number2=capacitBat[j];
      string r = static_cast<ostringstream*>( &(ostringstream() << Number2) )->str();
      String^ Cell3= gcnew String(r.c_str());
      capacitBat.erase(capacitBat.begin());

    array<String^>^row1 = gcnew array<String^>{
         Cell0 ,Cell1, Cell2, Cell3
      };
     array<Object^>^rows = {row1};
      System::Collections::IEnumerator^ myEnum = rows->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         array<String^>^rowArray = safe_cast<array<String^>^>(myEnum->Current);      
         dataGridView1->Rows->Add( rowArray );
      }

    }           

             }
private: System::Void B_LoadTest_Click(System::Object^  sender, System::EventArgs^  e) {

dataGridView2->ColumnCount = 4;
      dataGridView2->ColumnHeadersVisible = true;

      // Set the column header style.
      DataGridViewCellStyle ^ columnHeaderStyle = gcnew DataGridViewCellStyle;
      columnHeaderStyle->BackColor = Color::Aqua;
      columnHeaderStyle->Font = gcnew System::Drawing::Font( "Verdana",10,FontStyle::Bold );
      dataGridView2->ColumnHeadersDefaultCellStyle = columnHeaderStyle;

      // Set the column header names.
      dataGridView2->Columns[ 0 ]->Name = "";
      dataGridView2->Columns[ 1 ]->Name = "RAM";
      dataGridView2->Columns[ 2 ]->Name = "CPU";
      dataGridView2->Columns[ 3 ]->Name = "BAT";

      // Populate the rows.

    ReadXMLTestersResources reader1;
    int size1=reader1.lire_size();
    vector<string>MyTesters= reader1.Lire_testeur();
    vector<int> capacitRam1= reader1.lire_RAM();
    vector<int> capacitCPU1= reader1.lire_CPU( );
    vector<int> capacitBat1 = reader1.lire_BAT( );
    while(!MyTesters.empty())
    {
          int j =0;
        string f=MyTesters[j];
      String^ Cell0= gcnew String(f.c_str());
        MyTesters.erase( MyTesters.begin());

       int Number=capacitRam1[j];
       string g = static_cast<ostringstream*>( &(ostringstream() << Number) )->str();
       String^ Cell1= gcnew String(g.c_str());
       capacitRam1.erase(capacitRam1.begin());

        int Number1=capacitCPU1[j];
      string h = static_cast<ostringstream*>( &(ostringstream() << Number1) )->str();
       String^ Cell2= gcnew String(h.c_str());
       capacitCPU1.erase(capacitCPU1.begin());

      int Number2=capacitBat1[j];
      string r = static_cast<ostringstream*>( &(ostringstream() << Number2) )->str();
      String^ Cell3= gcnew String(r.c_str());
      capacitBat1.erase(capacitBat1.begin());

    array<String^>^row1 = gcnew array<String^>{
         Cell0 ,Cell1, Cell2, Cell3
      };
     array<Object^>^rows = {row1};
      System::Collections::IEnumerator^ myEnum = rows->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         array<String^>^rowArray = safe_cast<array<String^>^>(myEnum->Current);      
         dataGridView2->Rows->Add( rowArray );
      }

    }       

         }
private: System::Void B_Load_Gain_Matrix_Click(System::Object^  sender, System::EventArgs^  e) {
             ConnectedComponentSearch1 reader2;
             reader2.init_graph();
    vector<bool> manel=reader2.Breadth_First_Search("N1");
    vector<ConnectedComponent> ala= reader2.CC_calculation();
    reader2.m_edges;
             ReadEnvironmentXML1 reader;
    //ReadTestersResourcesXML reader1;
      int size=reader.lire_size();
    vector<string> myNodes= reader.lire_Nodes();
    vector<vector<int>> edgs=reader.lire_Links();
    vector<int> capacitRam= reader.lire_RAM();
    vector<int> capacitBat = reader.lire_BAT( ) ;
    vector<int> capacitCPU= reader.lire_CPU();
    vector<vector<int>>  lnk_val = reader.lire_Links_val();
    vector<int> maxp= reader.lire_MaxP();

             dataGridView3->ColumnCount =size ;
             dataGridView3->ColumnHeadersVisible = true;

      // Set the column header style.
      DataGridViewCellStyle ^ columnHeaderStyle = gcnew DataGridViewCellStyle;
      columnHeaderStyle->BackColor = Color::Aqua;
      columnHeaderStyle->Font = gcnew System::Drawing::Font( "Verdana",10,FontStyle::Bold );
      dataGridView3->ColumnHeadersDefaultCellStyle = columnHeaderStyle;

      // Set the column header names.

      for (int i =0;i<reader2.m_vertices_number;i++)
      {
            string f=reader2.m_vertices[i];
      String^ Cell0= gcnew String(f.c_str());
      dataGridView3->Columns[ i ]->Name = Cell0;
      }


      // Populate the rows.
    int d=0;
    const std::size_t w(100);
     const std::size_t h(100);
     vector<vector<int>>GainMatrix;
    for(unsigned int i(0); i < h; ++i)
      GainMatrix.emplace_back(std::vector<int>(w));
         int pied =-1;
        for (int i =0; i <ala.size(); i++ )
        { 
            for (int j=0; j<ala[i].m_nodes.size(); j++)  
            {
                pied++;
                string f=ala[i].m_nodes[j];
                cout<<"f="<<f<<endl;
                vector<int>naoufal = reader2.distance_calculation(ala[i], f);

                for( int a =0; a <naoufal.size(); a++ )
                {
                int Number=naoufal[a];
                string g = static_cast<ostringstream*>( &(ostringstream() << Number) )->str();
                String^ Cell2= gcnew String(g.c_str());

                array<String^>^row1 = gcnew array<String^>{
                Cell2
                    };
                    array<Object^>^rows = {row1};
                      System::Collections::IEnumerator^ myEnum = rows->GetEnumerator();
                      while ( myEnum->MoveNext() )
                      {
                         array<String^>^rowArray = safe_cast<array<String^>^>(myEnum->Current);      
                         dataGridView3->Rows->Add( rowArray );
                      }

                 }




            }
        }



         }
private: System::Void B_GecodeSolver_Click(System::Object^  sender, System::EventArgs^  e) {
         }
private: System::Void B_ShowResults_Click(System::Object^  sender, System::EventArgs^  e) {
            //this->Hide();
            // TestComponentsGainsVsNodesPlacement ^maForm2 = gcnew TestComponentsGainsVsNodesPlacement();
                //maForm2->Show();

             Form21 ^maForm2 = gcnew Form21();
             maForm2->Show();

         }
private: System::Void B_GenerateTestPlan_Click(System::Object^  sender, System::EventArgs^  e) {
             // Demande de confirmation
    if (MessageBox::Show(this, 
            "Sauvegarder le document?",
            "Sauvegarde", 
            MessageBoxButtons::YesNo,
            MessageBoxIcon::Question) == Windows::Forms::DialogResult::No)
        return;

             int m=5;
             int n=5;
             crerxmlfichier1 writer;
             writer.write_simple_doc2(n,m);
         }
private: System::Void B_Quit_Click(System::Object^  sender, System::EventArgs^  e) {

             Close();
         }
private: System::Void dataGridView2_CellContentClick(System::Object^  sender, System::Windows::Forms::DataGridViewCellEventArgs^  e) {
             dataGridView2->AutoResizeColumnHeadersHeight();

      // Resize all the row heights to fit the contents of all non-header cells.
     dataGridView2->AutoResizeRows(
            DataGridViewAutoSizeRowsMode::AllCellsExceptHeaders);

         }

private: System::Void dataGridView3_CellContentClick(System::Object^  sender, System::Windows::Forms::DataGridViewCellEventArgs^  e) {

             dataGridView3->AutoResizeColumnHeadersHeight();

      // Resize all the row heights to fit the contents of all non-header cells.
     dataGridView3->AutoResizeRows(
            DataGridViewAutoSizeRowsMode::AllCellsExceptHeaders);
         }
};
}

i wiill send you also my Form21 because i think i did implemented it also

#pragma once
#include "Form1.h"
#include <vector>
#include <string>

namespace interfaceProject {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;

    /// <summary>
    /// Description résumée de Form2
    /// </summary>
    public ref class Form2 : public System::Windows::Forms::Form
    {
    public:
        Form2()
            : Form()
        {
            InitializeComponent();
            //
            //TODO: ajoutez ici le code du constructeur
            //
        }

    protected:
        /// <summary>
        /// Nettoyage des ressources utilisées.
        /// </summary>
        ~Form2()
        {
            if (components)
            {
                delete components;
            }
        }

    private: System::Windows::Forms::DataGridView^  dataGridView1;
    protected: 

    private:
        /// <summary>
        /// Variable nécessaire au concepteur.
        /// </summary>
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
        /// <summary>
        /// Méthode requise pour la prise en charge du concepteur - ne modifiez pas
        /// le contenu de cette méthode avec l'éditeur de code.
        /// </summary>
        void InitializeComponent(void)
        {
            this->dataGridView1 = (gcnew System::Windows::Forms::DataGridView());
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView1))->BeginInit();
            this->SuspendLayout();
            // 
            // dataGridView1
            // 
            this->dataGridView1->ColumnHeadersHeightSizeMode = System::Windows::Forms::DataGridViewColumnHeadersHeightSizeMode::AutoSize;
            this->dataGridView1->Location = System::Drawing::Point(12, 12);
            this->dataGridView1->Name = L"dataGridView1";
            this->dataGridView1->Size = System::Drawing::Size(524, 150);
            this->dataGridView1->TabIndex = 1;
            this->dataGridView1->CellContentClick += gcnew System::Windows::Forms::DataGridViewCellEventHandler(this, &Form2::dataGridView1_CellContentClick);
            // 
            // Form2
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(566, 262);
            this->Controls->Add(this->dataGridView1);
            this->Name = L"Form2";
            this->Text = L"Form2";
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dataGridView1))->EndInit();
            this->ResumeLayout(false);

        }
#pragma endregion
    private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {

             }
    private: System::Void dataGridView1_CellContentClick(System::Object^  sender, System::Windows::Forms::DataGridViewCellEventArgs^  e) {
            dataGridView1->AutoResizeColumnHeadersHeight();

      // Resize all the row heights to fit the contents of all non-header cells.
     dataGridView1->AutoResizeRows(
            DataGridViewAutoSizeRowsMode::AllCellsExceptHeaders);
         // Set the column header names.

     // Create an unbound DataGridView by declaring a column count.
      dataGridView1->ColumnCount = 4;
      dataGridView1->ColumnHeadersVisible = true;

      // Set the column header style.
      DataGridViewCellStyle ^ columnHeaderStyle = gcnew DataGridViewCellStyle;
      columnHeaderStyle->BackColor = Color::Aqua;
      columnHeaderStyle->Font = gcnew System::Drawing::Font( "Verdana",10,FontStyle::Bold );
      dataGridView1->ColumnHeadersDefaultCellStyle = columnHeaderStyle;

      // Set the column header names.
      dataGridView1->Columns[ 0 ]->Name = "Recipe";
      dataGridView1->Columns[ 1 ]->Name = "Category";
      dataGridView1->Columns[ 2 ]->Name = "Main Ingredients";
      dataGridView1->Columns[ 3 ]->Name = "Rating";

      // Populate the rows.
      array<String^>^row1 = gcnew array<String^>{
         "Meatloaf","Main Dish","ground beef","**"
      };
      array<String^>^row2 = gcnew array<String^>{
         "Key Lime Pie","Dessert","lime juice, evaporated milk","****"
      };
      array<String^>^row3 = gcnew array<String^>{
         "Orange-Salsa Pork Chops","Main Dish","pork chops, salsa, orange juice","****"
      };
      array<String^>^row4 = gcnew array<String^>{
         "Black Bean and Rice Salad","Salad","black beans, brown rice","****"
      };
      array<String^>^row5 = gcnew array<String^>{
         "Chocolate Cheesecake","Dessert","cream cheese","***"
      };
      array<String^>^row6 = gcnew array<String^>{
         "Black Bean Dip","Appetizer","black beans, sour cream","***"
      };
      array<Object^>^rows = {row1,row2,row3,row4,row5,row6};
      System::Collections::IEnumerator^ myEnum = rows->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         array<String^>^rowArray = safe_cast<array<String^>^>(myEnum->Current);
         dataGridView1->Rows->Add( rowArray );
      }
             }
             }
    };
}

when ijust put the include (#include "Form21.h") it shows me these errors :

1>------ Début de la génération : Projet : interfaceProject, Configuration : Debug Win32 ------
1>  interfaceProject.cpp
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form21.h(139): error C2143: erreur de syntaxe : absence de ';' avant '}'
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form21.h(140): error C2059: erreur de syntaxe : '}'
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form21.h(140): error C2143: erreur de syntaxe : absence de ';' avant '}'
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form21.h(140): error C2059: erreur de syntaxe : '}'
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(333): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(333): error C2065: 'string' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(333): error C2065: 'myNodes' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(334): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(334): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(334): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(335): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(335): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(336): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(336): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(337): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(337): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(338): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(338): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(338): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(339): error C2065: 'vector' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(339): error C2062: type 'int' inattendu
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(341): error C2065: 'myNodes' : identificateur non déclaré
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(341): error C2228: la partie gauche de '.empty' doit avoir un class/struct/union
1>          le type est ''unknown-type''
1>c:\visual studio 2010\projects\interfaceproject\interfaceproject\Form1.h(341): fatal error C1903: impossible de récupérer à partir des erreurs précédentes ; arrêt de la compilation
========== Génération : 0 a réussi, 1 a échoué, 1 mis à jour, 0 a été ignoré ==========

and when i remove it form1 works fine!!!!! is that normal ????????

Yes, but I never see Form21(vingt et un) I see Form2(deux) as a class. There must be a name confusion somewhere I guess.

@ddanbe thank you for your help it is just like you said need an implementation for the form21.h , ineed just to mre focus on my work , thank you again have a good day :)

This question has already been answered. Start a new discussion instead.