1. Control Structures Part C – Groups of Controls
Lecture Set 5
Control Structures
Part C – Groups of Controls

2. Objectives
Learn first how to construct grouped controls with statically defined choices
(Later – not in this Lecture Set) Learn at least one way to populate a grouped control from a dynamically changeable source such as a simple sequential file or even a database
2/24/ :58 PM

3. Control Groups
Container controls are used to group control instances together
The GroupBox control is a container control
Visual Studio supports several other container controls
2/24/ :58 PM2/24/ :58 PM

4. The GroupBox Control (Syntax)
The BackColor and ForeColor properties define the color
Visual text appears in the Text property
2/24/ :58 PM2/24/ :58 PM

5. The RadioButton Control
The end user selects one button from a group of buttons
Members
The Text property contains the visible text
The Checked property defines whether the RadioButton is selected
The CheckedChanged event fires when the button is clicked
2/24/ :58 PM2/24/ :58 PM

6. Multicast Event Handlers (Introduction)
One event handler handles the same event for many control instances
The Handles clause contains a comma-separated list of control instances and event names
A period separates the control instance and event name
2/24/ :58 PM2/24/ :58 PM

7. Multicast Event Handlers (Example)
Handles click event for all 9 buttons on Tic-Tac-Toe board
Uses name (“btnrc”) attribute of button where r is the row ID and c the column ID of the button (0 <= r, c <= 2)
// “Wires” event handler to each of 9 buttons (part of nested loops)
this.boardView[row, col].Click += new System.EventHandler(this.Button_Click);
// One event handler wired to all 9 buttons on the board
private void Button_Click(object sender, EventArgs e) {
Button thisButton = (Button)sender;
thisButton.BackColor = Color.LightGoldenrodYellow;
string thisID = thisButton.Name.Substring(3, 2);
int rowID = (int)thisID[0] - (int)'0';
int colID = (int)thisID[1] - (int)'0';
((Button)sender).Enabled = false;
((Button)sender).Text = "C";
} // end Button Click
2/24/ :58 PM2/24/ :58 PM

8. Multi-cast Event Handlers (Another Example)
For more examples, look at Lecture Set 07, particularly:
LectureSet07XSender
LectureSet07XDynamic
2/24/ :58 PM2/24/ :58 PM