---
description: '.NET WPF component and application patterns'
applyTo: '**/*.xaml, **/*.cs'
---

## Summary

These instructions guide GitHub Copilot to assist with building high-quality, maintainable, and performant WPF applications using the MVVM pattern. It includes best practices for XAML, data binding, UI responsiveness, and .NET performance.

## Ideal project types

- Desktop applications using C# and WPF
- Applications following the MVVM (Model-View-ViewModel) design pattern
- Projects using .NET 8.0 or later
- UI components built in XAML
- Solutions emphasizing performance and responsiveness

## Goals

- Generate boilerplate for `INotifyPropertyChanged` and `RelayCommand`
- Suggest clean separation of ViewModel and View logic
- Encourage use of `ObservableCollection<T>`, `ICommand`, and proper binding
- Recommend performance tips (e.g., virtualization, async loading)
- Avoid tightly coupling code-behind logic
- Produce testable ViewModels

## Example prompt behaviors

### ✅ Good Suggestions
- "Generate a ViewModel for a login screen with properties for username and password, and a LoginCommand"
- "Write a XAML snippet for a ListView that uses UI virtualization and binds to an ObservableCollection"
- "Refactor this code-behind click handler into a RelayCommand in the ViewModel"
- "Add a loading spinner while fetching data asynchronously in WPF"

### ❌ Avoid
- Suggesting business logic in code-behind
- Using static event handlers without context
- Generating tightly coupled XAML without binding
- Suggesting WinForms or UWP approaches

## Technologies to prefer
- C# with .NET 8.0+
- XAML with MVVM structure
- `CommunityToolkit.Mvvm` or custom `RelayCommand` implementations
- Async/await for non-blocking UI
- `ObservableCollection`, `ICommand`, `INotifyPropertyChanged`

## Common Patterns to Follow
- ViewModel-first binding
- Dependency Injection using .NET or third-party containers (e.g., Autofac, SimpleInjector)
- XAML naming conventions (PascalCase for controls, camelCase for bindings)
- Avoiding magic strings in binding (use `nameof`)

## Sample Instruction Snippets Copilot Can Use

```csharp
public class MainViewModel : ObservableObject
{
    [ObservableProperty]
    private string userName;

    [ObservableProperty]
    private string password;

    [RelayCommand]
    private void Login()
    {
        // Add login logic here
    }
}
```

```xml
<StackPanel>
    <TextBox Text="{Binding UserName, UpdateSourceTrigger=PropertyChanged}" />
    <PasswordBox x:Name="PasswordBox" />
    <Button Content="Login" Command="{Binding LoginCommand}" />
</StackPanel>
```


---
Source: awesome-copilot (github/awesome-copilot) https://github.com/github/awesome-copilot/blob/cb64ad12e32737ae764becd6885462e9b4c7cb00/instructions/dotnet-wpf.instructions.md
MIT License

Copyright GitHub, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.