Introduction to computing

AS Computing Unit F452

 Building Applications ◦ Creating computer applications in Visual Studio ◦ Creating program code using VB.NET ◦ Testing Code (when it goes wrong!)

 First thing you need to do in every Computing class is open Visual Studio. It can take a while so be patient…

You will create a ‘Windows Form Application’that will allow you to choose and view a picturein the window that your program runs in.Follow the instructions on the following slidesto produce your first program!

TOOLBOX PROJECT / SOLUTION EXPLORERDESIGNWINDOW OBJECT PROPERTIES CODE VIEW

 Requirements: ◦ To choose an image file ◦ To show the chosen image file as a picture in a window of a program ◦ To be able to quit/close the program when required

 File ◦ New  Windows Form Application Give it the name ‘Picture Viewer’

 Go to the Properties Window ◦ Find Form 1 > Text ◦ Change the ‘Text’ property from ‘Form1’ to ‘Picture Viewer’ Click the Save icon at the top! (do this quite often to prevent losing work) Change the Form Size ◦ Form Properties > Size  Height > 500  Width > 350

 Double-click to add objects: ◦ Add a ‘Button’ from the Toolbox with properties:  Name – btnSelectPicture  Location – 295,10 (x and y coordinates!)  Size - 85,23  Text - Select Picture

 Right click on the button, then copy, then paste within the form This will be the ‘Quit’ Button with properties:  Name – btnQuit  Location – 295,40  Text - Quit

 Back to the Toolbox Double click on ‘PictureBox’ This need the following properties:  Name – picShowPicture  BorderStyle - FixedSingle  Location – 8,8 SAVE!!!

 Toolbox ◦ Double-click OpenFileDialog (in Dialogs category) ◦ Note that it is hidden at the bottom! Select OpenFileDialog and set properties: ◦ Name - ofdSelectPicture ◦ Filename - (leave this bit blank) ◦ Filter - Windows Bitmaps|*.BMP|JPEG Files|*.JPG ◦ Title - Select Picture

 Double-click on the ‘Select Picture’ button ◦ Now you can add code to make it do stuff! Enter the code from the following slides

Show the open file dialog box If ofdSelectPicture.ShowDialog = DialogResult.OK Then Load the picture into the picture box picShowPicture.Image = Image.FromFile(ofdSelectPicture.FileName) Show the name of the file in the forms caption Me.Text = "Picture Viewer(" & ofdSelectPicture.FileName & ")" End If

Close the window and exit the applicationMe.Close()

 Click SAVE! Click the green RUN (triangle) button at the top in the main toolbar Try choosing a picture! Click ‘Quit’ to close your program

1. What type of VB program creates a standard Windows program?2. What window is used to change attributes of a form or control in the IDE?3. How do you access the code of a control?4. What property of a picture box do you set to display an image?5. What is the default event for a button control?

1. Windows Form Application2. Properties Window3. Double-click an object in design view4. The IMAGE property5. The CLICK event

Introduction to computing

by Secondary School on Jan 02, 2012

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Introduction to computing — Presentation Transcript