StringToChar: identifier not found

#pragma once
 
#include <stdio.h>
#include <cmath>
#include <string.h>
#include <stdlib.h>
using namespace std;
namespace kursovaja {
 
    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::Runtime::InteropServices;
 
    /// <summary>
    /// Summary for Form1
    ///
    /// WARNING: If you change the name of this class, you will need to change the
    ///          'Resource File Name' property for the managed resource compiler tool
    ///          associated with all .resx files this class depends on.  Otherwise,
    ///          the designers will not be able to interact properly with localized
    ///          resources associated with this form.
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    public:
        Form1(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }
 
    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~Form1()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::Button^  button1;
    protected: 
    private: System::Windows::Forms::Button^  button2;
 
    private: System::Windows::Forms::Label^  label1;
    private: System::Windows::Forms::Label^  label2;
    private: System::Windows::Forms::Label^  label3;
    private: System::Windows::Forms::TextBox^  textBox1;
    private: System::Windows::Forms::TextBox^  textBox2;
    private: System::Windows::Forms::TextBox^  textBox3;
    private: System::Windows::Forms::PictureBox^  pictureBox1;
    private: System::Windows::Forms::DataGridView^  dg1;
 
    private: System::Windows::Forms::MenuStrip^  menuStrip1;
    private: System::Windows::Forms::OpenFileDialog^  openFileDialog1;
    private: System::Windows::Forms::SaveFileDialog^  saveFileDialog1;
    private: System::Windows::Forms::DataGridViewTextBoxColumn^  Column1;
    private: System::Windows::Forms::DataGridViewTextBoxColumn^  Column2;
    private: System::Windows::Forms::ToolStripMenuItem^  saveToolStripMenuItem;
    private: System::Windows::Forms::ToolStripMenuItem^  loadToolStripMenuItem;
 
        /// <summary>
        /// Required designer variable.
        /// </summary>
        System::ComponentModel::Container ^components;
 
#pragma region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        void InitializeComponent(void)
        {
            this->button1 = (gcnew System::Windows::Forms::Button());
            this->button2 = (gcnew System::Windows::Forms::Button());
            this->label1 = (gcnew System::Windows::Forms::Label());
            this->label2 = (gcnew System::Windows::Forms::Label());
            this->label3 = (gcnew System::Windows::Forms::Label());
            this->textBox1 = (gcnew System::Windows::Forms::TextBox());
            this->textBox2 = (gcnew System::Windows::Forms::TextBox());
            this->textBox3 = (gcnew System::Windows::Forms::TextBox());
            this->pictureBox1 = (gcnew System::Windows::Forms::PictureBox());
            this->dg1 = (gcnew System::Windows::Forms::DataGridView());
            this->Column1 = (gcnew System::Windows::Forms::DataGridViewTextBoxColumn());
            this->Column2 = (gcnew System::Windows::Forms::DataGridViewTextBoxColumn());
            this->menuStrip1 = (gcnew System::Windows::Forms::MenuStrip());
            this->saveToolStripMenuItem = (gcnew System::Windows::Forms::ToolStripMenuItem());
            this->loadToolStripMenuItem = (gcnew System::Windows::Forms::ToolStripMenuItem());
            this->openFileDialog1 = (gcnew System::Windows::Forms::OpenFileDialog());
            this->saveFileDialog1 = (gcnew System::Windows::Forms::SaveFileDialog());
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->pictureBox1))->BeginInit();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dg1))->BeginInit();
            this->menuStrip1->SuspendLayout();
            this->SuspendLayout();
            // 
            // button1
            // 
            this->button1->Location = System::Drawing::Point(268, 21);
            this->button1->Name = L"button1";
            this->button1->Size = System::Drawing::Size(75, 23);
            this->button1->TabIndex = 0;
            this->button1->Text = L"button1";
            this->button1->UseVisualStyleBackColor = true;
            this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);
            // 
            // button2
            // 
            this->button2->Location = System::Drawing::Point(268, 50);
            this->button2->Name = L"button2";
            this->button2->Size = System::Drawing::Size(75, 23);
            this->button2->TabIndex = 1;
            this->button2->Text = L"button2";
            this->button2->UseVisualStyleBackColor = true;
            this->button2->Click += gcnew System::EventHandler(this, &Form1::button2_Click);
            // 
            // label1
            // 
            this->label1->AutoSize = true;
            this->label1->Location = System::Drawing::Point(35, 21);
            this->label1->Name = L"label1";
            this->label1->Size = System::Drawing::Size(35, 13);
            this->label1->TabIndex = 3;
            this->label1->Text = L"label1";
            // 
            // label2
            // 
            this->label2->AutoSize = true;
            this->label2->Location = System::Drawing::Point(35, 48);
            this->label2->Name = L"label2";
            this->label2->Size = System::Drawing::Size(35, 13);
            this->label2->TabIndex = 4;
            this->label2->Text = L"label2";
            // 
            // label3
            // 
            this->label3->AutoSize = true;
            this->label3->Location = System::Drawing::Point(35, 74);
            this->label3->Name = L"label3";
            this->label3->Size = System::Drawing::Size(35, 13);
            this->label3->TabIndex = 5;
            this->label3->Text = L"label3";
            // 
            // textBox1
            // 
            this->textBox1->Location = System::Drawing::Point(94, 21);
            this->textBox1->Name = L"textBox1";
            this->textBox1->Size = System::Drawing::Size(100, 20);
            this->textBox1->TabIndex = 6;
            // 
            // textBox2
            // 
            this->textBox2->Location = System::Drawing::Point(94, 48);
            this->textBox2->Name = L"textBox2";
            this->textBox2->Size = System::Drawing::Size(100, 20);
            this->textBox2->TabIndex = 7;
            // 
            // textBox3
            // 
            this->textBox3->Location = System::Drawing::Point(94, 74);
            this->textBox3->Name = L"textBox3";
            this->textBox3->Size = System::Drawing::Size(100, 20);
            this->textBox3->TabIndex = 8;
            // 
            // pictureBox1
            // 
            this->pictureBox1->Location = System::Drawing::Point(38, 150);
            this->pictureBox1->Name = L"pictureBox1";
            this->pictureBox1->Size = System::Drawing::Size(409, 263);
            this->pictureBox1->TabIndex = 9;
            this->pictureBox1->TabStop = false;
            // 
            // dg1
            // 
            this->dg1->ColumnHeadersHeightSizeMode = System::Windows::Forms::DataGridViewColumnHeadersHeightSizeMode::AutoSize;
            this->dg1->Columns->AddRange(gcnew cli::array< System::Windows::Forms::DataGridViewColumn^  >(2) {this->Column1, this->Column2});
            this->dg1->Location = System::Drawing::Point(453, 2);
            this->dg1->Name = L"dg1";
            this->dg1->Size = System::Drawing::Size(240, 150);
            this->dg1->TabIndex = 10;
            // 
            // Column1
            // 
            this->Column1->HeaderText = L"Column1";
            this->Column1->Name = L"Column1";
            // 
            // Column2
            // 
            this->Column2->HeaderText = L"Column2";
            this->Column2->Name = L"Column2";
            // 
            // menuStrip1
            // 
            this->menuStrip1->Items->AddRange(gcnew cli::array< System::Windows::Forms::ToolStripItem^  >(2) {this->saveToolStripMenuItem, 
                this->loadToolStripMenuItem});
            this->menuStrip1->Location = System::Drawing::Point(0, 0);
            this->menuStrip1->Name = L"menuStrip1";
            this->menuStrip1->Size = System::Drawing::Size(764, 24);
            this->menuStrip1->TabIndex = 11;
            this->menuStrip1->Text = L"menuStrip1";
            // 
            // saveToolStripMenuItem
            // 
            this->saveToolStripMenuItem->Name = L"saveToolStripMenuItem";
            this->saveToolStripMenuItem->Size = System::Drawing::Size(46, 20);
            this->saveToolStripMenuItem->Text = L"Save";
            this->saveToolStripMenuItem->Click += gcnew System::EventHandler(this, &Form1::saveToolStripMenuItem_Click);
            // 
            // loadToolStripMenuItem
            // 
            this->loadToolStripMenuItem->Name = L"loadToolStripMenuItem";
            this->loadToolStripMenuItem->Size = System::Drawing::Size(47, 20);
            this->loadToolStripMenuItem->Text = L"Load";
            this->loadToolStripMenuItem->Click += gcnew System::EventHandler(this, &Form1::loadToolStripMenuItem_Click);
            // 
            // openFileDialog1
            // 
            this->openFileDialog1->FileName = L"openFileDialog1";
            this->openFileDialog1->FileOk += gcnew System::ComponentModel::CancelEventHandler(this, &Form1::openFileDialog1_FileOk);
            // 
            // saveFileDialog1
            // 
            this->saveFileDialog1->FileOk += gcnew System::ComponentModel::CancelEventHandler(this, &Form1::saveFileDialog1_FileOk);
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(764, 467);
            this->Controls->Add(this->dg1);
            this->Controls->Add(this->pictureBox1);
            this->Controls->Add(this->textBox3);
            this->Controls->Add(this->textBox2);
            this->Controls->Add(this->textBox1);
            this->Controls->Add(this->label3);
            this->Controls->Add(this->label2);
            this->Controls->Add(this->label1);
            this->Controls->Add(this->button2);
            this->Controls->Add(this->button1);
            this->Controls->Add(this->menuStrip1);
            this->MainMenuStrip = this->menuStrip1;
            this->Name = L"Form1";
            this->Text = L"Form1";
            this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->pictureBox1))->EndInit();
            (cli::safe_cast<System::ComponentModel::ISupportInitialize^  >(this->dg1))->EndInit();
            this->menuStrip1->ResumeLayout(false);
            this->menuStrip1->PerformLayout();
            this->ResumeLayout(false);
            this->PerformLayout();
 
        }
        float x1,y1,x2,y2; 
        double x,y,min,max,interval;
        array<float>^ a;                                    
        array<float>^ b;
        Bitmap^ bmp;
        Graphics^ gr;
    String^ FileName; 
  char* StrToChar(System::String^ string) 
{
  return (char*)(void*)Marshal::StringToHGlobalAnsi(string);
}
    
#pragma endregion
    private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
                 dg1->Rows->Clear();
                
                 min=Convert::ToInt32(textBox1->Text);
                  max=Convert::ToInt32(textBox2->Text);
                  interval=Convert::ToInt32(textBox3->Text);
                 for(x=min;x<max;x=x+interval)
                 {
                    if (x==1)
                        x++;
                    if (x==-1)
                        x++;
                    
                    y=sin(x)*x;
                        
                    dg1->Rows->Add(x,y);
 
                 }
             }
private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e) {
             a = gcnew array<float>(dg1->RowCount);
             b = gcnew array<float>(dg1->RowCount);
 
            
            
             Pen^ p=gcnew Pen(pictureBox1->BackColor);
             SolidBrush^ sb=gcnew SolidBrush(pictureBox1->BackColor);
           gr->FillRectangle(sb,0,0,pictureBox1->Width,pictureBox1->Height);
 
            
                a[0]=Convert::ToDouble(dg1->Rows[0]->Cells[0]->Value)+pictureBox1->Width/2;
                b[0]=Convert::ToDouble(dg1->Rows[0]->Cells[1]->Value)+pictureBox1->Height/2;
 
 
             for(int i=0;i<dg1->RowCount-1;i++) 
             {
                x1=Convert::ToDouble(dg1->Rows[i]->Cells[0]->Value);
                y1=Convert::ToDouble(dg1->Rows[i]->Cells[1]->Value);
                x2=Convert::ToDouble(dg1->Rows[i+1]->Cells[0]->Value);
                y2=Convert::ToDouble(dg1->Rows[i+1]->Cells[1]->Value);
                x1=x1+pictureBox1->Width/2;
                y1=y1+pictureBox1->Height/2;
                x2=x2+pictureBox1->Width/2;
                y2=y2+pictureBox1->Height/2;
 
 
gr->DrawLine(Pens::Black,x1,y1,x2,y2);
a[i+1]=x2;
b[i+1]=y2;
            }
             pictureBox1->Image=bmp;
            
             Drawing::Font^ drawFont = gcnew Drawing::Font("Arial", 13);
            
             {
             gr->DrawString("X",drawFont,Brushes::Black,400,150);
            gr->DrawString("0",drawFont,Brushes::Black,204,135);
            gr->DrawString("0",drawFont,Brushes::Black,204,10);
             }
             
            
        gr->DrawLine (Pens::Black,0, pictureBox1->Height/2, pictureBox1->Width,pictureBox1->Height/2);
             gr->DrawLine (Pens::Black,pictureBox1->Width/2, 0, pictureBox1->Width/2,pictureBox1->Height);
                             for (int a=0;a<pictureBox1->Width;a+=5)
                    gr->DrawLine (Pens::Black,a, pictureBox1->Height/2-3,a,pictureBox1->Height/2+3);
 
             for (int a=0;a<pictureBox1->Height;a+=5)
        gr->DrawLine (Pens::Black, pictureBox1->Width/2-3,a,pictureBox1->Width/2+3,a);
             
 
 
              
 
         }
         
private: System::Void openFileDialog1_FileOk(System::Object^  sender, System::ComponentModel::CancelEventArgs^  e) {
              openFileDialog1->ShowDialog();
             Bitmap^ bmp=gcnew Bitmap(openFileDialog1->FileName);
             pictureBox1->Image=bmp;
         }
private: System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e) {
              bmp=gcnew Bitmap(pictureBox1->Width,pictureBox1->Height);
             gr=Graphics::FromImage(bmp);
         }
private: System::Void saveFileDialog1_FileOk(System::Object^  sender, System::ComponentModel::CancelEventArgs^  e) {
             if(saveFileDialog1->ShowDialog()==Windows::Forms::DialogResult::OK)
             {
                String^ FileName;
                FileName=saveFileDialog1->FileName;
                float xtab,ytab;
 
    
 
char * char_filename = (char *)((void*)System::Runtime::InteropServices::Marshal::StringToHGlobalAnsi(FileName));
FILE* f=fopen(char_filename,"wb");
System::Runtime::InteropServices::Marshal::FreeHGlobal(cli::safe_cast<System::IntPtr>(char_filename));
                for(int i=0;i<dg1->RowCount;i++)
                {
                    xtab=Convert::ToDouble(dg1->Rows[i]->Cells[0]->Value);
                    ytab=Convert::ToDouble(dg1->Rows[i]->Cells[1]->Value);
                    fwrite(&xtab,sizeof(float),1,f);
                    fwrite(&ytab,sizeof(float),1,f);
                }
                fclose(f);
             }
         }
private: System::Void saveToolStripMenuItem_Click(System::Object^  sender, System::EventArgs^  e) {
              if(saveFileDialog1->ShowDialog()==Windows::Forms::DialogResult::OK)
             {
                 bmp->Save(saveFileDialog1->FileName);
             }
         }
         
         
private: System::Void loadToolStripMenuItem_Click(System::Object^  sender, System::EventArgs^  e) {
                   if (openFileDialog1->ShowDialog()== Windows::Forms::DialogResult::OK)
                  {
                        String^ FileName;
                FileName=openFileDialog1->FileName;
                      float xtab,ytab;
                FILE *f;
                
             f=fopen(StringToChar(FileName), "rb");
             while (feof(f))
             {
                 fread (&xtab,sizeof (float),1,f);
                 if (feof(f))
                 {
                    fread (&ytab,sizeof (float),1,f);
                    
                 }
             }}
         }
};
};