Stephens' C# Programming with Visual Studio® 2010 24-Hour Trainer

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LESSON 9 Creating and displaying new Forms

The following code demonstrates this technique. The main form’s Load event handler creates and dis-

plays a new

ColorForm. When the user clicks the main form’s Red button, its event handler changes the

remote form’s

BackColor and ForeColor properties. The startup form also contains green and blue

buttons that have similar event handlers.

// The remote form we will manipulate.

ColorForm remoteColorForm;

// Create and display the remote form.

private void Form1_Load(object sender, EventArgs e)

{

remoteColorForm = new ColorForm();

remoteColorForm.Show();

}

// Make the color form red.

private void redButton_Click(object sender, EventArgs e)

{

remoteColorForm.BackColor = Color.Red;

remoteColorForm.ForeColor = Color.Pink;

}

Here the remoteColorForm variable is declared outside of the event handlers. The form’s Load event

handler initializes the variable and displays the remote form. The

redButton_Click event handler

uses it. Because the variable is declared outside of the event handlers, they can all use it. (Lesson 13

has more to say about when and where variables are available to the code.)

In the previous example, I moved the code that creates the ColorForm into the

main form’s

Load event handler. If that code stayed in a Button’s Click event

handler, the user could click it a bunch of times and create many different

forms. Each time the prog