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

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LESSON 25 Fine-Tuning Classes

In the form’s

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Load event handler, create some ShapeRectangles and ShapeEllipses and

add them to the list.

Give the form a

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CheckBox labeled Colored. In its CheckedChanged event handler, invalidate

the form to force a redraw.

In the form’s

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Paint event handler, redraw the form by looping through the Shapes in the

list. If the

CheckBox is checked, invoke the Shape objects’ Draw method, passing it the pen

and brush

Pens.Blue and Brushes.LightBlue. If the CheckBox is not checked, invoke the

Draw method with no parameters.

Hints

If gr is the Graphics object, then you can use these methods to draw:

gr.Clear(this.BackColor)

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— Clears the object with the form’s background color.

gr.FillRectangle(

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brush, rect) — Fills a rectangle defined by the Rectangle rect with

brush.

gr.DrawRectangle(

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pen, rect) — Outlines a rectangle defined by the Rectangle rect

with

pen.

gr.FillEllipse(

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brush, rect) — Fills an ellipse defined by the Rectangle rect with brush.

gr.DrawEllipse(

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pen, rect) — Outlines an ellipse defined by the Rectangle rect with pen.

In the

Paint event handler, draw on the Graphics object provided by the event handler’s

e.Graphics parameter.

Step-by-Step

Start a new program and create the

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Shape class.

Give the class a

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using System.Drawing directive.

1. Simply place the using directive at the top of the file.

Give the class a property named

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Bounds