Transcript Windows Forms - University of South Florida

Windows Forms II
Chapter 20
1
RadioButton / GroupBox Controls
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Used to solicit a multiple choice input.
Radio buttons work as a group.
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Selecting one unselects any previous
choice.
The GroupBox defines the group.
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Expand “All Windows Forms” in Toolbox.
Drag GroupBox to the form.
Drag four radio buttons from the Toolbox
and drop inside the GroupBox.
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You can also copy and paste controls.
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Ctrl-C, Ctrl-V
2
GroupBox Properties
Text Property
Location and size are normally set interactively via the designer.
The usual appearance properties are available.
3
RadioButton Properties
Text
Checked is true for a button that is selected. (Max of 1 per group.)
4
Add an OK Button
5
Code for Button Click Event
enum Classification {Unknown, Freshman, Sophomore, Junior, Senior};
Classification year = Classification.Unknown;
private void btnOK_Click(object sender, System.EventArgs e)
{
if (rbFreshman.Checked)
year = Classification.Freshman;
else if (rbSophomore.Checked)
year = Classification.Sophomore;
else if (rbJunior.Checked)
year = Classification.Junior;
else if (rbSenior.Checked)
year = Classification.Senior;
}
if (year == Classification.Unknown)
MessageBox.Show("Please select year");
else
MessageBox.Show("You will be recorded as a " + year.ToString());
End of Section
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The PictureBox Control
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Allows you to include images on your form.
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Typically a jpeg or gif file
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Other possibilities.
Important Properties:
 Image (Browse to file)
 Location
 Size
 SizeMode
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Normal, StretchImage, AutoSize, CenterImage, Zoom
BorderStyle
7
The PictureBox Control
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Need an image file?
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Try google > images
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From search on University of South Florida
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Image file is in Downloads area of class web site:
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http://www.cse.usf.edu/~turnerr/Software_Systems_Development/
Downloads/USF_Bull.gif
Download to desktop
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The PictureBox Control
9
Setting the Image Property
Select the Image property.
Click on the elipses (...) button.
10
Setting the Image Property
Click on Import.
11
Setting the Image
Navigate to the image file.
Select the file and click Open.
12
Setting the Image
Click OK.
13
Setting the Image
The image file has been copied into the project.
14
SizeMode Values
From the Help page for SizeMode:
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Valid values for this property are taken from the
PictureBoxSizeMode enumeration.
By default, in PictureBoxSizeMode.Normal mode, the Image is
placed in the upper left corner of the PictureBox, and any part
of the image too big for the PictureBox is clipped.
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PictureBoxSizeMode.Zoom causes the image to be stretched or
shrunk to fit the PictureBox, while maintaining the aspect ratio.
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Using the PictureBoxSizeMode.StretchImage value causes the
image to stretch to fit the PictureBox.
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Using the PictureBoxSizeMode.AutoSize value causes the control
to resize to always fit the image.
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Using the PictureBoxSizeMode.CenterImage value causes the
image to be centered in the client area.
15
The PictureBox Control
Set size mode to Zoom.
Build and run.
16
SizeMode Zoom
SizeMode = Zoom
17
SizeMode Normal
SizeMode = Normal
18
CenterImage
SizeMode = CenterImage
19
AutoSize
SizeMode = Autosize
Most of the PictureBox falls outside the form.
20
AutoSize
Window resized to hold entire PictureBox control.
21
The PictureBox Control
Conclusions:
 Try to match size of actual image to size that
you need on the form.
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If not, Zoom is usually the best bet.
But, at least, be sure the ratio of height to width
is about the same.
End of Section
22
Where is the image?
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It's embedded in the program
You don't need to retain or deploy the original image file.
23
Form1.resx
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In the project folder, you can drill down
and find the file.
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Form1.resx
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Form1.resx
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Form1.resx
27
Form1.resx
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End of Section
The ComboBox Control
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“Combination” of text entry box and
dropdown list.
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Select from list or enter text.
Important Properties:
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Items (Collection of strings to display.)
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DropDownStyle
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Can be set using the designer or by program.
Simple
DropDown
DropDownList
Text
Text Entry Only
Text Entry or Select
Select Only
Whatever was selected or entered
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The ComboBox Control
Set name to cbYear.
30
Setting the Choices
31
Setting the Choices
Click OK.
32
Getting the User’s Choice
Build and run.
33
Program Running
34
The ComboBox Control
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After clicking on the arrow:
35
The ComboBox Control
After user selects Sophomore
36
Getting the User’s Choice
End of Section
37
Handling the FormClosing Event
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In Design View, select the form (by
clicking anywhere on the background.)
In the Properties window, select Events.
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Beside “FormClosing” type the name
that you want to give to the event
handler (e.g., FormIsClosing)
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(Lightening bolt icon at top of window.)
Don't use the event name, FormClosing.
Press Enter.
38
Setting the Event Handler
39
Handling the FormClosing Event
This creates the following stub in the code file:
private void FormIsClosing(
object sender,
System.ComponentModel.CancelEventArgs e)
{
}
This function will be called when the user clicks the Close button
on the form.
40
Using a MessageBox to Get User Input
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Add this code inside the FormIsClosing function.
DialogResult result =
MessageBox.Show("Are you sure you want to quit?",
"Confirm",
MessageBoxButtons.YesNo,
MessageBoxIcon.Question);
e.Cancel = (result == DialogResult.No);
41
MessageBox Example
MessageBox.Show("Are you sure you want to quit?",
"Confirm",
MessageBoxButtons.YesNo,
MessageBoxIcon.Question);
42
Add a Close Button
43
Close Button Click Event Handler
private void btnClose_Click(object sender, EventArgs e)
{
this.Close();
}
44
We still get the FormClosing Event
End of Section
45
Summany
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Visual Studio makes it easy to create
simple Windows forms applications.
There is an enormous amount of
information about Windows forms.
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Only a small amount of it is necessary in
order to create simple applications.
Need to be aware of what exists.
Need to be able to find what you need
when you need it.
End of Presentation
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