Step 10: Write Code for Additional Buttons and a Check Box

Now you're ready to complete the other four methods. You could copy and paste this code, but if you want to learn the most from this tutorial, type the code and use IntelliSense.

For a video version of this topic, see Tutorial 1: Create a Picture Viewer in Visual Basic - Video 5 or Tutorial 1: Create a Picture Viewer in C# - Video 5.

Note

As a best practice: Always comment your code. Comments are information for a person to read, and it's worth the time to make your code understandable. Everything on a comment line is ignored by the program. In Visual C#, you comment a line by typing two forward slashes at the beginning (//), and in Visual Basic you comment a line by starting with a single quotation mark (').

To write code for additional buttons and a check box

• Add the following code.

  Private Sub clearButton_Click() Handles clearButton.Click
      ' Clear the picture.
      PictureBox1.Image = Nothing 
  End Sub 
  
  Private Sub backgroundButton_Click() Handles backgroundButton.Click
      ' Show the color dialog box. If the user clicks OK, change the 
      ' PictureBox control's background to the color the user chose. 
      If ColorDialog1.ShowDialog() = DialogResult.OK Then
          PictureBox1.BackColor = ColorDialog1.Color
      End If 
  End Sub 
  
  Private Sub closeButton_Click() Handles closeButton.Click
      ' Close the form.
      Close()
  End Sub 
  
  Private Sub CheckBox1_CheckedChanged() Handles CheckBox1.CheckedChanged
      ' If the user selects the Stretch check box, change  
      ' the PictureBox's SizeMode property to "Stretch". If the user  
      ' clears the check box, change it to "Normal". 
      If CheckBox1.Checked Then
          PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
      Else
          PictureBox1.SizeMode = PictureBoxSizeMode.Normal
      End If 
  End Sub
  

  private void clearButton_Click(object sender, EventArgs e)
  {
      // Clear the picture.
      pictureBox1.Image = null;
  }
  
  private void backgroundButton_Click(object sender, EventArgs e)
  {
      // Show the color dialog box. If the user clicks OK, change the 
      // PictureBox control's background to the color the user chose. 
      if (colorDialog1.ShowDialog() == DialogResult.OK)
          pictureBox1.BackColor = colorDialog1.Color;
  }
  
  private void closeButton_Click(object sender, EventArgs e)
  {
      // Close the form. 
      this.Close();
  }
  
  private void checkBox1_CheckedChanged(object sender, EventArgs e)
  {
      // If the user selects the Stretch check box,  
      // change the PictureBox's 
      // SizeMode property to "Stretch". If the user clears 
      // the check box, change it to "Normal".
      if (checkBox1.Checked)
          pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
      else
          pictureBox1.SizeMode = PictureBoxSizeMode.Normal;
  }
  

To continue or review

• To go to the next tutorial step, see Step 11: Run Your Program and Try Other Features.

• To return to the previous tutorial step, see Step 9: Review, Comment, and Test Your Code.