14.3 Event Handling in Programming

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Questions and Answers

What is the primary purpose of a PictureBox control?

To create a RadioButton group

To handle user input

To display an image (correct)

To display a MessageBox

How do you add a resource, such as an image, to a project?

Double-click the project's Properties node and add the resource through the Resources tab (correct)

Drag and drop the file into the Solution Explorer

Use the OpenFileDialog to select the file

Create a new folder in the project directory and add the file manually

What is the benefit of embedding images in the application?

It improves the performance of the application

It increases the complexity of the application

It prevents problems of using several separate files (correct)

It reduces the size of the application

What type of control is used to enable users to select options for a MessageBox?

RadioButton Signup and view all the answers

What is the primary purpose of a RadioButton control?

To enable users to select one option from a group Signup and view all the answers

What is the primary function of the Anchor property in a GUI control?

To attach the control to a specific side of the form Signup and view all the answers

What is a common event associated with a PictureBox control?

Click Signup and view all the answers

What is the purpose of docking in GUI control layout?

To fill an entire side or area of the parent container Signup and view all the answers

What type of file is commonly displayed in a PictureBox control?

Bitmap image Signup and view all the answers

What happens when you anchor a control to the right and bottom sides of a form?

The control remains at a fixed distance from the sides of the form Signup and view all the answers

What is the purpose of the Padding property in a form?

To specify the distance between docked controls and the edges Signup and view all the answers

Where do you go to add a resource to a project?

Properties node Signup and view all the answers

What is the primary purpose of the Click event in GUI programming?

To trigger an action when a control is clicked Signup and view all the answers

What is the base class for GUI controls in Windows Forms?

Control Signup and view all the answers

What happens when you execute an application with anchored controls and enlarge the form?

The controls are resized to fit the new form size Signup and view all the answers

What is the relationship between a docked control and its parent container?

The control spans an entire side of the container Signup and view all the answers

What is the first parameter that an event handler receives when it's called?

An object reference to the object that generated the event Signup and view all the answers

Where does Visual Studio place the auto-generated GUI code?

In the Designer.cs file of the Form Signup and view all the answers

What is the purpose of the partial modifier in the Form's class declaration?

To allow the Form's class to be split among multiple files Signup and view all the answers

What is the name of the method that is called when the Form is created?

InitializeComponent Signup and view all the answers

What is the purpose of a delegate in the event-handling mechanism?

To connect an event handler to a control's event Signup and view all the answers

What is the name of the file that contains the auto-generated code for the Form?

Designer.cs Signup and view all the answers

What is the type of the second parameter that an event handler receives when it's called?

An EventArgs-derived object Signup and view all the answers

What is the purpose of the InitializeComponent method?

To initialize the Form's controls Signup and view all the answers

Study Notes

Event Handling

Each event handler receives two parameters: an object reference (sender) and an EventArgs object (or derived class) containing additional event information.
The auto-generated code for GUI events is placed in the Designer.cs file of the Form.
The partial modifier allows the Form's class to be split among multiple files.

Event-Handling Mechanism

Event handlers are connected to a control's events via special objects called delegates.

Control Properties and Layout

Controls derive from class Control (namespace System.Windows.Forms).
Class Control's properties and methods include:
- Anchor property to set a control's anchoring to the sides of the container
- Dock property to attach a control to a container, allowing it to span an entire side or fill the entire area
- Padding property to specify the distance between docked controls and the edges
Anchoring causes controls to remain at a fixed distance from the sides of the container.
Docking allows a control to span an entire side of its parent container or fill the entire container.

PictureBoxes

A PictureBox displays an image.
Common PictureBox properties and events include:
- Image property to set the displayed image
- Click event to respond to user interaction
Resources can be added programmatically by embedding images in the app, preventing file dependency issues.
To add a resource:
- Double click the project's Properties node in the Solution Explorer.
- Click the Resources tab.
- At the top of the Resources tab, click the down arrow next to the Add Resource button and select Add Existing File…
- Locate the files you wish to add and click the Open button.
- Save your project.

CheckBoxes and RadioButtons

RadioButtons can be used to enable users to select options for a MessageBox.

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Description

This quiz covers event handling in programming, including event handler parameters and EventArgs objects. It discusses how event handlers receive two parameters when called, including an object reference and an EventArgs object containing additional event information.