MAUI BindingContext绑定

方法一：在CS代码中绑定

// MainPage.xaml.cs
public partial class MainPage : ContentPage
{
    private readonly IServiceProvider _serviceProvider;
    public MainPage(IServiceProvider serviceProvider)
    {
        InitializeComponent();
        _serviceProvider = serviceProvider;
        BindingContext = _serviceProvider.GetService<MyViewModel>();
    }
}

方法二：使用XAML中x:Static

定义：

public class VMLocator
{
    public static T GetRequiredService<T>() where T : class
    {
        if (App.Current?.Handler.MauiContext == null)
            throw new NullReferenceException("App.Current.Handler.MauiContext为空");

        return App.Current.Handler.MauiContext.Services.GetRequiredService<T>();            
    }

    public static MainPageViewModel GetMainPageViewModel => GetRequiredService<MainPageViewModel>();
}

绑定1：静态绑定

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:vm ="clr-namespace:MauiTest.ViewModel"
             x:Class="MauiTest.MainPage"
             BindingContext="{x:Static vm:VMLocator.GetMainPageViewModel}"

绑定2：通过资源绑定（注意：通过这个方法时类VMLocator中的GetMainPageViewModel不能定义为静态属性）

定义资源

<?xml version = "1.0" encoding = "UTF-8" ?>
<Application xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:MauiTest"
             xmlns:vm="clr-namespace:MauiTest.ViewModel"
             x:Class="MauiTest.App">
    <Application.Resources>
        <ResourceDictionary>
            <vm:VMLocator x:Key="SrcVMLocator"></vm:VMLocator> //定义VMLocator资源
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Resources/Styles/Colors.xaml" />
                <ResourceDictionary Source="Resources/Styles/Styles.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

绑定资源

<ContentPage.BindingContext>
    <Binding Source="{x:StaticResource SrcVMLocator}" Path="GetMainPageViewModel"></Binding>
</ContentPage.BindingContext>

方法三：使用自定义标记扩展

定义：

public class ViewModelLocator : IMarkupExtension
{
    public string ViewModelType { get; set; } = "";

    public object ProvideValue(IServiceProvider serviceProvider)
    {
        if (string.IsNullOrEmpty(ViewModelType))
            throw new ArgumentException("ViewModelType cannot be null or empty.");

        var type = Type.GetType(ViewModelType);
        if (type == null)
            throw new ArgumentException($"Type {ViewModelType} not found.");

        var viewModel = App.Current.Handler.MauiContext.Services.GetService(type);

        return viewModel;
    }
}

绑定：

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"    
             xmlns:vm ="clr-namespace:MauiTest.ViewModel"
             x:Class="MauiTest.MainPage"
             BindingContext="{vm:ViewModelLocator ViewModelType=MauiTest.ViewModel.MainPageViewModel}"

方法一及方法三在xaml进行属性绑定时无提示问题解决方案

方法一：使用 x:DataType 指令
x:DataType 指令可以帮助XAML编辑器识别绑定的类型，从而提供智能提示。

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"    
             xmlns:vm ="clr-namespace:MauiTest.ViewModel"
             x:Class="MauiTest.MainPage"
             x:DataType="vm:MainPageViewModel"
             >