Xaml Xamarin自定义控件命令不'；行不通

我希望自定义控件在单击按钮时触发命令

    public partial class TestControl : ContentView
    {
        public TestControl()
        {
            InitializeComponent();
            Test = new Command(async () =>
            {
                await Application.Current.MainPage.DisplayAlert("asd", "asd", "asd");
            });
        }

        public ICommand Test { get; }
    }

---

根据您的描述和代码，您希望在自定义控件中创建Icommand

我做了一个示例，您可以看看，首先创建Icommand BindableProperty

测试控制：

<ContentView.Content>
    <StackLayout>
        <Button x:Name="btn1" Text="press" />
    </StackLayout>
</ContentView.Content>

  public partial class TestControl : ContentView
{
    public ICommand CommandInButton
    {
        get { return (ICommand)GetValue(CommandInButtonProperty); }
        set { SetValue(CommandInButtonProperty, value); }
    }
   
    public static readonly BindableProperty CommandInButtonProperty = BindableProperty.Create(
    propertyName: "CommandInButton",
    returnType: typeof(ICommand),
    declaringType: typeof(TestControl),
    defaultValue: null,
    propertyChanged: CommandInButtonPropertyChanged);

    private static void CommandInButtonPropertyChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var control = (TestControl)bindable;
        control.btn1.Command= (ICommand)newValue;
    }

    public TestControl()
    {
        InitializeComponent();
    }
    
}

公共部分类TestControl:ContentView
{
公共ICommand命令按钮
{
获取{return（ICommand）GetValue（CommandInButtonProperty）；}
set{SetValue（CommandInButtonProperty，value）；}
}
公共静态只读BindableProperty命令InButtonProperty=BindableProperty.Create(
propertyName:“命令按钮”，
returnType:typeof（ICommand），
declaringType:typeof（测试控制），
defaultValue:null，
propertyChanged：命令按钮propertyChanged）；
私有静态void命令ButtonPropertyChanged（BindableObject bindable、object oldValue、object newValue）
{
var-control=（TestControl）可绑定；
control.btn1.Command=（ICommand）newValue；
}
公共测试控制（）
{
初始化组件（）；
}
}

您可以访问内容页：

 <local:TestControl CommandInButton="{Binding Test}" />

 public ICommand Test { get; }
    public Page3()
    {
        InitializeComponent();

        Test = new Command(async () =>
        {
            await Application.Current.MainPage.DisplayAlert("asd", "asd", "asd");
        });

        this.BindingContext = this;
       
    }

公共ICommand测试{get；}
公共网页3（）
{
初始化组件（）；
测试=新命令（异步（）=>
{
等待应用程序。当前。主页。显示警报（“asd”、“asd”、“asd”）；
});
this.BindingContext=this；
}

日志中是否有任何特定错误？这很有效！下一步是使命令可绑定。我想先让它在控制范围内工作。但我现在要用这个密码。非常感谢。

[Mono] Warning: Degraded allocation.  Consider increasing nursery-size if the warning persists.
[Mono] GC_TAR_BRIDGE bridges 0 objects 0 opaque 0 colors 0 colors-bridged 0 colors-visible 52 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.03ms tarjan 0.03ms scc-setup 0.02ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.01ms
[Mono] GC_BRIDGE: Complete, was running for 0.14ms
[Mono] GC_MINOR: (Concurrent start) time 22.50ms, stw 56.42ms promoted 900K major size: 16448K in use: 15445K los size: 1024K in use: 871K
[Mono] GC_MAJOR_CONCURRENT_START: (Degraded mode overflow)
[mpanyname.eTAp] Explicit concurrent copying GC freed 406(29KB) AllocSpace objects, 0(0B) LOS objects, 50% free, 1601KB/3MB, paused 499us total 7.510ms
[Mono] GC_TAR_BRIDGE bridges 42 objects 43 opaque 1 colors 42 colors-bridged 42 colors-visible 42 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.04ms tarjan 0.02ms scc-setup 0.03ms gather-xref 0.07ms xref-setup 0.01ms cleanup 0.02ms
[Mono] GC_BRIDGE: Complete, was running for 8.62ms
[Mono] GC_MAJOR_CONCURRENT_FINISH: (finishing) time 734.57ms, stw 22.44ms los size: 1024K in use: 231K
[Mono] GC_MAJOR_SWEEP: major size: 16960K in use: 15533K
[Mono] GC_TAR_BRIDGE bridges 0 objects 0 opaque 0 colors 0 colors-bridged 0 colors-visible 42 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.04ms tarjan 0.02ms scc-setup 0.03ms gather-xref 0.07ms xref-setup 0.01ms cleanup 0.02ms
[Mono] GC_BRIDGE: Complete, was running for 0.24ms
[Mono] GC_MINOR: (Concurrent start) time 19.60ms, stw 38.71ms promoted 300K major size: 32640K in use: 31136K los size: 1024K in use: 504K
[Mono] GC_MAJOR_CONCURRENT_START: (Degraded mode overflow)
[mpanyname.eTAp] Explicit concurrent copying GC freed 3(16KB) AllocSpace objects, 0(0B) LOS objects, 50% free, 1601KB/3MB, paused 402us total 7.396ms
[Mono] GC_TAR_BRIDGE bridges 40 objects 41 opaque 1 colors 40 colors-bridged 40 colors-visible 40 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.05ms tarjan 0.02ms scc-setup 0.01ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.19ms
[Mono] GC_BRIDGE: Complete, was running for 9.27ms
[Mono] GC_MAJOR_CONCURRENT_FINISH: (finishing) time 520.80ms, stw 26.07ms los size: 1024K in use: 373K
[Mono] GC_MAJOR_SWEEP: major size: 32640K in use: 30767K
[Mono] Warning: Degraded allocation.  Consider increasing nursery-size if the warning persists.
[Mono] GC_TAR_BRIDGE bridges 0 objects 0 opaque 0 colors 0 colors-bridged 0 colors-visible 40 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.05ms tarjan 0.02ms scc-setup 0.01ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.01ms
[Mono] GC_BRIDGE: Complete, was running for 0.16ms
[Mono] GC_MINOR: (Concurrent start) time 17.46ms, stw 43.08ms promoted 100K major size: 48336K in use: 46517K los size: 2048K in use: 941K
[Mono] GC_MAJOR_CONCURRENT_START: (Degraded mode overflow)
[mpanyname.eTAp] Explicit concurrent copying GC freed 3(16KB) AllocSpace objects, 0(0B) LOS objects, 50% free, 1601KB/3MB, paused 398us total 7.155ms
[Mono] GC_TAR_BRIDGE bridges 40 objects 41 opaque 1 colors 40 colors-bridged 40 colors-visible 40 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.05ms tarjan 0.02ms scc-setup 0.02ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.11ms
[Mono] GC_BRIDGE: Complete, was running for 8.62ms
[Mono] GC_MAJOR_CONCURRENT_FINISH: (finishing) time 291.47ms, stw 30.74ms los size: 2048K in use: 667K
[Mono] GC_MAJOR_SWEEP: major size: 48208K in use: 46018K
[Mono] GC_TAR_BRIDGE bridges 0 objects 0 opaque 0 colors 0 colors-bridged 0 colors-visible 40 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.05ms tarjan 0.02ms scc-setup 0.02ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.01ms
[Mono] GC_BRIDGE: Complete, was running for 0.12ms
[Mono] GC_MINOR: (Concurrent start) time 19.62ms, stw 47.45ms promoted 34K major size: 64576K in use: 62420K los size: 2048K in use: 667K
[Mono] GC_MAJOR_CONCURRENT_START: (Degraded mode overflow)
[mpanyname.eTAp] Explicit concurrent copying GC freed 3(16KB) AllocSpace objects, 0(0B) LOS objects, 50% free, 1601KB/3MB, paused 403us total 5.366ms
[Mono] GC_TAR_BRIDGE bridges 40 objects 41 opaque 1 colors 40 colors-bridged 40 colors-visible 40 xref 3 cache-hit 0 cache-semihit 0 cache-miss 0 setup 0.20ms tarjan 0.02ms scc-setup 0.01ms gather-xref 0.01ms xref-setup 0.01ms cleanup 0.12ms
[Mono] GC_BRIDGE: Complete, was running for 7.67ms
[Mono] GC_MAJOR_CONCURRENT_FINISH: (finishing) time 198.38ms, stw 31.63ms los size: 2048K in use: 667K
[Mono] GC_MAJOR_SWEEP: major size: 64400K in use: 61857K
[libc] Fatal signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0xff4f2fbc in tid 21571 (mpanyname.eTApp), pid 21571 (mpanyname.eTApp)

<ContentView.Content>
    <StackLayout>
        <Button x:Name="btn1" Text="press" />
    </StackLayout>
</ContentView.Content>

  public partial class TestControl : ContentView
{
    public ICommand CommandInButton
    {
        get { return (ICommand)GetValue(CommandInButtonProperty); }
        set { SetValue(CommandInButtonProperty, value); }
    }
   
    public static readonly BindableProperty CommandInButtonProperty = BindableProperty.Create(
    propertyName: "CommandInButton",
    returnType: typeof(ICommand),
    declaringType: typeof(TestControl),
    defaultValue: null,
    propertyChanged: CommandInButtonPropertyChanged);

    private static void CommandInButtonPropertyChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var control = (TestControl)bindable;
        control.btn1.Command= (ICommand)newValue;
    }

    public TestControl()
    {
        InitializeComponent();
    }
    
}

 <local:TestControl CommandInButton="{Binding Test}" />

 public ICommand Test { get; }
    public Page3()
    {
        InitializeComponent();

        Test = new Command(async () =>
        {
            await Application.Current.MainPage.DisplayAlert("asd", "asd", "asd");
        });

        this.BindingContext = this;
       
    }