Avalonia first meeting

When we meet a new language, we write “Hello world”, and when we meet a new UI, we create a notebook. Here I want to show a simple example of friendship with the Framework korssplatformennym the GUI AvaloniaUI .



First, install the required template.

To do this, save this repository on your machine.

Open the console and write:

dotnet new --install [путь до скачанного шаблона]

And create a starting project:

dotnetnewavalonia.mvvm-oNotebook

Add a simple markup as in wpf in the MainWindow.xaml file.

<Windowxmlns="https://github.com/avaloniaui"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:vm="clr-namespace:Notebook.ViewModels;assembly=Notebook"Icon="resm:Notebook.Assets.avalonia-logo.ico"Title="Notebook"><!--Биндим горячие клавиши--><Window.KeyBindings><KeyBindingGesture="Ctrl+O"Command="{Binding Open}" /><KeyBindingGesture="Ctrl+S"Command="{Binding Save}" /></Window.KeyBindings><Design.DataContext><vm:MainWindowViewModel /></Design.DataContext><!--Стандартная разметочка гридом--><Grid><Grid.RowDefinitions><RowDefinitionHeight="Auto" /><RowDefinitionHeight="*" /></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinitionWidth="*" /></Grid.ColumnDefinitions><!--Менюшечка--><MenuGrid.Row="0"Grid.Column="0"><MenuItemHeader="File"><MenuItemHeader="Open"Command="{Binding Open}" /><MenuItemHeader="Save As"Command="{Binding Save}" /></MenuItem></Menu><!--Основное текстовое поле--><TextBoxGrid.Row="1"Grid.Column="0"Text="{Binding Data}"AcceptsReturn="True" /></Grid></Window>

C mvvm everything is a little different here, since ReactiveUI is used by default.

So in the MainWindowViewModel.cs file we add:

privatestring _data;
        publicstringData
        {
            get => _data;
            set => this.RaiseAndSetIfChanged(ref _data, value);
        }

But in contrast to the default wpf, avaloniya allows the team to bind commands directly to the methods.
And it is also worth noting that the file dialogs in this framework are only asynchronous.
Then opening the document will look like this:

publicasyncTaskOpen()
        {
            var dialog = new OpenFileDialog();
            string[] result = null;
            dialog.Filters.Add(new FileDialogFilter() {Name = "Text", Extensions = {"txt"}});
            result = awaitdialog.ShowAsync();
            if (result != null)
            {
                Data = File.ReadAllText(result.First());
            }
        }

And here is the preservation:

publicasyncTaskSave()
        {
            var dialog = new SaveFileDialog();
            dialog.Filters.Add(new FileDialogFilter() 
            {Name = "Text", Extensions = {"txt"}});
            varresult = awaitdialog.ShowAsync(newMainWindow());
            if (result != null)
            {
                File.WriteAllText(result, Data);
            }
        }

In order for the application to run on Linux, you will have to add another dependency: Avalonia.Skia.Linux.Natives.

But unfortunately, not all assemblies will be able to display our window. Ubuntu (including Mate) does an excellent job on both the large (x64) architecture and the arm, but Raspbian obviously fails.


PS

The project is incredibly interesting and enjoyable. It has a lot of targeted platforms, including apple ones, we hope that soon it will work fine on all platforms.