Hello World
This tutorial walks through building a simple Hermes application with native menus.
Project Setup
Create a new console application:
bash
dotnet new console -n HelloHermes
cd HelloHermes
dotnet add package HermesBasic Window
Replace the contents of Program.cs:
csharp
using Hermes;
var window = new HermesWindow()
.SetTitle("Hello Hermes")
.SetSize(800, 600)
.Center()
.LoadHtml("""
<!DOCTYPE html>
<html>
<head>
<style>
body {
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
margin: 0;
background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
color: white;
}
h1 { font-size: 3rem; }
</style>
</head>
<body>
<h1>Hello, Hermes!</h1>
</body>
</html>
""");
window.WaitForClose();Run it:
bash
dotnet runAdding Menus
Native menus are a core feature of Hermes. Let's add a menu bar:
csharp
using Hermes;
var window = new HermesWindow()
.SetTitle("Hello Hermes")
.SetSize(800, 600)
.Center();
// Configure menus before showing the window
window.MenuBar
.AddMenu("File", file =>
{
file.AddItem("New", "file.new", item => item.WithAccelerator("Ctrl+N"))
.AddItem("Open...", "file.open", item => item.WithAccelerator("Ctrl+O"))
.AddSeparator()
.AddItem("Exit", "file.exit", item => item.WithAccelerator("Alt+F4"));
})
.AddMenu("Help", help =>
{
help.AddItem("About", "help.about");
});
// Handle menu clicks
window.MenuBar.ItemClicked += itemId =>
{
Console.WriteLine($"Menu clicked: {itemId}");
if (itemId == "file.exit")
{
window.Close();
}
};
window.LoadHtml("<h1>Hello with Menus!</h1>");
window.WaitForClose();Window Configuration
Hermes uses a fluent API for window configuration:
csharp
var window = new HermesWindow()
.SetTitle("My App")
.SetSize(1024, 768) // Initial size
.SetMinSize(640, 480) // Minimum size
.SetMaxSize(1920, 1080) // Maximum size
.Center() // Center on screen
.SetResizable(true) // Allow resizing
.SetTopMost(false) // Not always on top
.SetDevToolsEnabled(true) // Enable F12 dev tools
.RememberWindowState(); // Persist size/positionEvents
Handle window events:
csharp
window
.OnClosing(() => Console.WriteLine("Window closing..."))
.OnResized((w, h) => Console.WriteLine($"Resized to {w}x{h}"))
.OnFocusIn(() => Console.WriteLine("Focused"))
.OnFocusOut(() => Console.WriteLine("Lost focus"));Loading Content
Three ways to load content:
csharp
// Load a URL
window.Load("https://example.com");
// Load HTML directly
window.LoadHtml("<h1>Hello!</h1>");
// Load from a custom scheme (for bundled assets)
window.RegisterCustomScheme("app", path =>
{
var content = LoadAssetFromBundle(path);
return (content, "text/html");
});
window.Load("app://index.html");Complete Example
Here's a complete hello world with all features:
csharp
using Hermes;
// Optional: Pre-warm WebView for faster startup (Windows)
HermesWindow.Prewarm();
var window = new HermesWindow()
.SetTitle("Hello Hermes")
.SetSize(800, 600)
.Center()
.SetDevToolsEnabled(true)
.RememberWindowState();
window.MenuBar
.AddMenu("File", file =>
{
file.AddItem("Exit", "file.exit", item => item.WithAccelerator("Ctrl+Q"));
});
window.MenuBar.ItemClicked += itemId =>
{
if (itemId == "file.exit") window.Close();
};
window.LoadHtml("""
<!DOCTYPE html>
<html>
<body style="font-family: system-ui; text-align: center; padding: 50px;">
<h1>Hello, Hermes!</h1>
<p>Press Ctrl+Q or use File > Exit to close.</p>
</body>
</html>
""");
window.WaitForClose();Next Steps
- Blazor Quick Start — Use Blazor for your UI
- Menus Guide — Advanced menu patterns
- HermesWindow API — Full API reference