Car Inventory Using a Slider

Practical Learning: Starting the Exercise

1. Start Microsoft Visual Basic .NET and create a new Windows Application named CarInventory1
2. Save the following pictures, with their default names, in the folder that contains the current project (if you are using Microsoft Visual Basic .NET 2003, after you have created the CarInventory1 project, two other folders with name bin and obj are created; therefore, save these pictures in the bin folder inside of the CarInventory1 folder):
    
3. Test the application
4. Close it and return to Visual Studio .NET

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. On the main menu, click Project -> Add Class
2. Set the name of the class to ListOfCars and press Enter
3. Create the class as follows:
    

   Public Class ListOfCars Public Make As String Public Model As String Public CarYear As Int16 Public Doors As Byte Public CarPicture As String End Class

4. Double-click an empty area of the form
5. Before using the cars, declare a global array of ListOfCars just under the Inherits line. Name the array variable Car as follows:
    

   Public Class Form1 Inherits System.Windows.Forms.Form Dim Car(10) As ListOfCars

6. To initialize the array and the slider, implement the Load event as follows:
    

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Car(0) = New ListOfCars Car(0).Make = "Honda" Car(0).Model = "Civic" Car(0).CarYear = 1998 Car(0).Doors = 4 Car(0).CarPicture = "Civic1.bmp" Car(1) = New ListOfCars Car(1).Make = "Hyundai" Car(1).Model = "Elantra" Car(1).CarYear = 1996 Car(1).Doors = 4 Car(1).CarPicture = "Elantra.bmp" Car(2) = New ListOfCars Car(2).Make = "Ford" Car(2).Model = "Escape" Car(2).CarYear = 2003 Car(2).Doors = 5 Car(2).CarPicture = "FordEscape1.bmp" Car(3) = New ListOfCars Car(3).Make = "Ford" Car(3).Model = "Escort" Car(3).CarYear = 1997 Car(3).Doors = 2 Car(3).CarPicture = "FordEscort1.bmp" Car(4) = New ListOfCars Car(4).Make = "Mercury" Car(4).Model = "Grand Marquis" Car(4).CarYear = 2001 Car(4).Doors = 4 Car(4).CarPicture = "GrandMarquis.bmp" Car(5) = New ListOfCars Car(5).Make = "Mercury" Car(5).Model = "Mystique" Car(5).CarYear = 2000 Car(5).Doors = 4 Car(5).CarPicture = "Mystique.bmp" Car(6) = New ListOfCars Car(6).Make = "Lincoln" Car(6).Model = "Navigator" Car(6).CarYear = 2003 Car(6).Doors = 5 Car(6).CarPicture = "Navigator1.bmp" Car(7) = New ListOfCars Car(7).Make = "Nissan" Car(7).Model = "Sentra" Car(7).CarYear = 1997 Car(7).Doors = 2 Car(7).CarPicture = "Sentra.bmp" Car(8) = New ListOfCars Car(8).Make = "Ford" Car(8).Model = "Focus" Car(8).CarYear = 2002 Car(8).Doors = 4 Car(8).CarPicture = "Focus.bmp" Car(9) = New ListOfCars Car(9).Make = "Ki" Car(9).Model = "Sephia" Car(9).CarYear = 2003 Car(9).Doors = 4 Car(9).CarPicture = "Sephia.bmp" End Sub

7. When the user slides the track bar, we will update the values of the controls depending on the selected car.
   Get back to the form and double-click the TrackBar control to access its OnScroll event
8. Implement it as follows:
    

   Private Sub trbSlider_Scroll(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles trbSlider.Scroll ' Get the index of the current value of the track bar - 1 Dim CurPos As Int16 = trbSlider.Value ' Based on the current index, retrieve the values of the ' current car and assign each to the corresponding control txtMake.Text = Car(CurPos).Make txtModel.Text = Car(CurPos).Model txtYear.Text = Car(CurPos).CarYear.ToString() txtDoors.Text = Car(CurPos).Doors.ToString() pctCarPicture.Image = Drawing.Image.FromFile(Car(CurPos).CarPicture) End Sub Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click Close() End Sub

9. Test the application