Car Inventory Using a Slider
 
Car Inventory

Introduction

This small application uses a dialog box on which the user can review a list of cars.

Prerequisites:

 

Creating the Application

This application was used to study or review the Track Bar control. We simply expand it here to include other controls that can provide more information about the car that is displaying.

Practical Learning: Starting the Exercise
  1. Start Microsoft Visual C++ .Net and create a new Windows  named CarInventory1
      
  2. Click Open
  3. Save the following pictures, with their default names, in the folder that contains the current project (if you are using Microsoft Visual C++ .Net 2003, after you have created the CarInventory1 project, another folder with the same name, CarInventory1, is created; therefore, save these pictures in the CarInventory1 folder inside of the primary CarInventory1 folder):
     
  4. Test the application
  5. Close it and return to Visual Studio

Designing the Application
  1. Design the form as follows:
     
    Control Text Name Additional Properties
    Group Box Car Description    
    Label Make:    
    TextBox Honda txtMake  
    Label Model:    
    TextBox Civic txtModel  
    Label Year:    
    TextBox 1998 txtYear  
    Label Doors:    
    TextBox 4 txtDoors  
    PictureBox   pctCarPicture Image: Select Civic1.bmp
    TrackBar   trbSlider Minimum: 1
    TickStyle: TopLeft
  2. Save everything
 

Coding the Application
  1. Right-click the form and click View Code
  2. To store the values for the controls of the form, in the top section of the file, create a managed structure named CLisOfCars as follows:
      
    namespace CarInventory1
{
	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;

	__gc struct CListOfCars
	{
		String *Make;
		String *Model;
		unsigned int CarYear;
		unsigned int Doors;
		String *CarPicture;
	};

	/// <summary> 
	/// Summary for Form1
	///
  3. Before using the cars, declare a managed array of CListOfCars just under InitializeComponents. Name the array variable Car as follows:
      
    private:
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		void InitializeComponent(void)	
		
		static CListOfCars *Car[] = __gc new CListOfCars*[10];
  4. To initialize the array and the slider, return to the form. Double-click an empty area of the form to access its OnLoad() event and implement it as follows:
      
    private: System::Void Form1_Load(System::Object *  sender, System::EventArgs *  e)
			 {
				 Car[0] = new CListOfCars;
				 Car[0]->Make = S"Honda";
				 Car[0]->Model = S"Civic";
				 Car[0]->CarYear = 1998;
				 Car[0]->Doors = 4;
				 Car[0]->CarPicture = S"Civic1.bmp";
				 
				 Car[1] = new CListOfCars;
				 Car[1]->Make = S"Hyundai";
				 Car[1]->Model = S"Elantra";
				 Car[1]->CarYear = 1996;
				 Car[1]->Doors = 4;
				 Car[1]->CarPicture = S"Elantra.bmp";
				 
				 Car[2] = new CListOfCars;
				 Car[2]->Make = S"Ford";
				 Car[2]->Model = S"Escape";
				 Car[2]->CarYear = 2003;
				 Car[2]->Doors = 5;
				 Car[2]->CarPicture = S"FordEscape1.bmp";
				 
				 Car[3] = new CListOfCars;
				 Car[3]->Make = S"Ford";
				 Car[3]->Model = S"Escort";
				 Car[3]->CarYear = 1997;
				 Car[3]->Doors = 2;
				 Car[3]->CarPicture = S"FordEscort1.bmp";

				 Car[4] = new CListOfCars;
				 Car[4]->Make = "Mercury";
				 Car[4]->Model = "Grand Marquis";
				 Car[4]->CarYear = 2001;
				 Car[4]->Doors = 4;
				 Car[4]->CarPicture = S"GrandMarquis.bmp";

				 Car[5] = new CListOfCars;
				 Car[5]->Make = "Mercury";
				 Car[5]->Model = "Mystique";
				 Car[5]->CarYear = 2000;
				 Car[5]->Doors = 4;
				 Car[5]->CarPicture = S"Mystique.bmp";

				 Car[6] = new CListOfCars;
				 Car[6]->Make = "Lincoln";
				 Car[6]->Model = "Navigator";
				 Car[6]->CarYear = 2003;
				 Car[6]->Doors = 5;
				 Car[6]->CarPicture = S"Navigator1.bmp";

				 Car[7] = new CListOfCars;
				 Car[7]->Make = "Nissan";
				 Car[7]->Model = "Sentra";
				 Car[7]->CarYear = 1997;
				 Car[7]->Doors = 2;
				 Car[7]->CarPicture = S"Sentra.bmp";

				 Car[8] = new CListOfCars;
				 Car[8]->Make = "Ford";
				 Car[8]->Model = "Focus";
				 Car[8]->CarYear = 2002;
				 Car[8]->Doors = 4;
				 Car[8]->CarPicture = S"Focus.bmp";

				 Car[9] = new CListOfCars;
				 Car[9]->Make = "Kia";
				 Car[9]->Model = "Sephia";
				 Car[9]->CarYear = 2003;
				 Car[9]->Doors = 4;
				 Car[9]->CarPicture = S"Sephia.bmp";
			 }
  5. When the user slides the track bar, we will update the values of the selected car and we will call the OnPaint() event of the form to change the picture of the car.
    Get back to the form and double-click the TrackBar control to access its OnScroll event
  6. Implement it as follows:
      
    private: System::Void trbSlider_Scroll(System::Object *  sender, System::EventArgs *  e)
{
        // Get the index of the current value of the track bar - 1
        int CurPos = this->trbSlider->Value - 1;

        // Based on the current index, retrieve the values of the
        // current car and assign each to the corresponding control 
        this->txtMake->Text	= this->Car[CurPos]->Make;
        this->txtModel->Text	= this->Car[CurPos]->Model;
        this->txtYear->Text	= this->Car[CurPos]->CarYear.ToString();
        this->txtDoors->Text	= this->Car[CurPos]->Doors.ToString(); 
        this->pctCarPicture->Image = Drawing::Image::FromFile(Car[CurPos]->CarPicture);
 }
  7. Test the application
 
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