Introduction
Microsoft has released
version 2.0 of the Visual Basic 2005 Power Packs; the kit may be downloaded from
here (http://msdn2.microsoft.com/en-us/vbasic/bb735936.aspx). Among other
things, the kit contains a collection of drawing primitive controls in the form
of an oval shape, a rectangle shape, and a line shape.
Figure 1: Using the
Drawing Primitives from the Visual Basic 2005 Power Pack 2.0
Installed Controls
Upon installation of the
tools; those items will appear in the toolbox under the heading of Visual Basic
Power Packs v2.0. After the installation, you should see the Print Form, Line
Shape, Oval Shape, and Rectangle Shape controls in the toolbox section. This
article only addresses the drawing primitives.
Features.
Adding to a Form
In order to use a
control, just drag the control from the toolbox and drop it onto the form as you
would any other toolbox control; alternatively the controls may be added in code
and added to the control collection.
Figure 2: Power Packs
Section of the Toolbox
Resize and Reposition
Once the drawing controls
have been added to the page, the user may click on a control which in turn
results in the display of the controls resizing handles. With the resizing
handles present, the user may resize the oval or rectangle, or resize and
reposition the beginning and end points of the line.
Figure
3: Manipulating a Control at Design Time
Control Properties
Each controls properties
are exposed in the IDE property grid upon selection of the control. The user may
set fill colors and styles, border thicknesses, gradient effects, and other
control related properties from this interface. Such properties may also be
manipulated in code at run time.
Figure
3: Setting Control Properties in the Property Grid
Control Events
The controls are
configured to respond to a number of common events, by writing event handlers
for these events is it possible to create responsive instances of the
controls. In the example provided, the three oval controls are configured to
show a roll-over effect when the mouse passes into and out of the control, and
to respond to a click event.
The following code is used to alter the fill gradient color property of an oval
control whenever the mouse enters the controls boundaries.
Private
Sub OvalShape1_MouseEnter(ByVal
sender As System.Object,
ByVal e
As
System.EventArgs) Handles OvalShape1.MouseEnter
OvalShape1.FillGradientColor =
Color.CornflowerBlue
End
Sub
And this code is used to
restore the fill gradient color to its previous state once the mouse leaves the
controls boundaries.
Private
Sub OvalShape1_MouseLeave(ByVal
sender As System.Object,
ByVal e
As
System.EventArgs) Handles OvalShape1.MouseLeave
OvalShape1.FillGradientColor =
Color.FromArgb(255, 255, 192)
End
Sub
Here, a click event
handler is added for the same control and is used to manage the visible property
on three line symbol controls also added to this page.
Private
Sub OvalShape1_Click(ByVal
sender As System.Object,
ByVal e As
System.EventArgs) Handles OvalShape1.Click
LineShape1.Visible =
True
LineShape2.Visible =
False
LineShape3.Visible =
False
End
Sub
Summary
Overall, the drawing
primitives are a useful set of controls that may be used to enhance the
appearance of an application GUI. The Microsoft site
(http://msdn2.microsoft.com/en-us/vbasic/bb735936.aspx) is soliciting opinions
and suggestions for additional controls and enhancements to the existing
controls. Some additions that come to mind might be the inclusion of a
transparent background label and a drop shadow enhancement to the existing
controls (and the mentioned label control).
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