**Course Title:** Mastering C#: From Fundamentals to Advanced Programming **Section Title:** Building Desktop Applications with Windows Forms and WPF **Topic:** Create a basic desktop application using Windows Forms or WPF.(Lab topic) **Objective:** In this lab topic, you will create a basic desktop application using Windows Forms or WPF. You will learn how to design a user interface, write event handlers, and work with controls to create a fully functional desktop application. **Prerequisites:** * Familiarity with C# syntax and Windows Forms or WPF basics * Visual Studio installed on your machine **Getting Started with Windows Forms:** Windows Forms is a built-in library in .NET Framework for building desktop applications. To create a new Windows Forms project in Visual Studio, follow these steps: 1. Open Visual Studio and click on "Create a new project" 2. Search for "Windows Forms App" and select the template 3. Choose the desired framework (e.g., .NET Core 3.1) 4. Name your project and click "Create" **Designing the User Interface:** To design the user interface, you can use the Visual Studio designer tool. Here's how to add a button and a label to your form: 1. Open the Form1.cs [Design] view 2. Drag and drop a Button from the Toolbox to the form 3. Double-click on the button to create a click event handler 4. Drag and drop a Label from the Toolbox to the form 5. Double-click on the label to create a label text property **Writing Event Handlers:** Event handlers are methods that respond to user interactions, such as button clicks. To write an event handler, follow these steps: 1. Double-click on the button to create a click event handler 2. In the code editor, write the event handler code 3. To update the label text, use the label.Text property Here's an example of a button click event handler: ```csharp private void button1_Click(object sender, EventArgs e) { label1.Text = "Button clicked!"; } ``` **Working with Controls:** Controls are UI elements that allow users to interact with your application. Here's how to work with controls: 1. Add a control to your form, such as a TextBox 2. Double-click on the control to create an event handler 3. Use the control's properties and methods to update its behavior Here's an example of working with a TextBox control: ```csharp private void textBox1_TextChanged(object sender, EventArgs e) { label1.Text = textBox1.Text; } ``` **Getting Started with WPF:** WPF is a more modern and powerful library for building desktop applications. To create a new WPF project in Visual Studio, follow these steps: 1. Open Visual Studio and click on "Create a new project" 2. Search for "WPF App" and select the template 3. Choose the desired framework (e.g., .NET Core 3.1) 4. Name your project and click "Create" **Designing the User Interface:** To design the user interface, you can use XAML (eXtensible Application Markup Language). Here's how to add a button and a label to your window: ```xml <Window x:Class="WpfApp1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <Button Content="Click me!" Click="Button_Click" HorizontalAlignment="Left" Margin="12,12,0,0" VerticalAlignment="Top" Width="75"/> <Label x:Name="label1" Content="Status" HorizontalAlignment="Left" Margin="103,18,0,0" VerticalAlignment="Top"/> </Grid> </Window> ``` **Writing Event Handlers:** Event handlers are similar to those in Windows Forms. To write an event handler, follow these steps: 1. Create an event handler method in your code-behind file (e.g., MainWindow.xaml.cs) 2. Use the event handler method to update the label text Here's an example of a button click event handler: ```csharp private void Button_Click(object sender, RoutedEventArgs e) { label1.Content = "Button clicked!"; } ``` **Working with Controls:** Controls are similar to those in Windows Forms. Here's how to work with controls: 1. Add a control to your window, such as a TextBox 2. Use the control's properties and methods to update its behavior Here's an example of working with a TextBox control: ```csharp private void TextBox_TextChanged(object sender, TextChangedEventArgs e) { label1.Content = textBox1.Text; } ``` **Lab Exercise:** Create a new Windows Forms or WPF project and design a simple calculator application with buttons for numbers 0-9, operators (+, -, \*, /), and a label to display the result. Here's a starting point for your lab exercise: https://docs.microsoft.com/en-us/visualstudio/get-started/csharp/tutorial-windows-forms **Additional Resources:** * Windows Forms documentation: https://docs.microsoft.com/en-us/dotnet/desktop/winforms/ * WPF documentation: https://docs.microsoft.com/en-us/dotnet/desktop/wpf/ **Do you have any questions or need help?**