hello world

The classic hello world

First, ensure everything is ready to start developping.

The minimal C.R.O.W. application

Create a new empty C# project and add the Crow NuGet package and one backend. For now, other backend than Cairo are experimental.

mkdir helloworld
cd helloworld
dotnet new console
dotnet add package Crow --prerelease
dotnet add package Crow.CairoBackend --prerelease

The resulting .csproj file should look something like this:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Crow" Version="1.0.1-beta"/>
    <PackageReference Include="Crow.CairoBackend" Version="1.0.1-beta" />
  </ItemGroup>
</Project>

The Interface class is the crow application base class, it controls inputs (keyboard, mouse, ....) and rendering.

static void Main(string[] args) {
  using (Interface app = new Interface ()) {
    app.Initialized += (sender, e)
      => app.LoadIMLFragment (@"<Label Text='Hello World' />");
    app.Run ();
  }

At this point, you have a working Crow Application loading a simple Label.

Usualy, the main application class will be derived from the Interface class:

class MyApplication : Interface	{
  static void Main (string[] args) {
    using (MyApplication app = new MyApplication ())
      app.Run ();

Then, instead of using the Initialized event to load ui components, you may override the OnInitialized Method of the Interface:

protected override void OnInitialized () {
  base.OnInitialized ();//the base method just raises the Initilized event.
  LoadIMLFragment (@"<Label Text='Hello World' />");
}

Ui components may be also directly instantiated in code instead of using IML, target Interface must be specified on manual widget creation:

AddWidget (new Label (this) { Text = "Hello World" });

Source