Xamarin 按钮不适用于 mvvm-light Relaycommand

Question

在我的 Xamrin 表单代码中，我配置了 MVVM light 即使我在 xaml 页面中为命令设置了属性，RelayCommand 也没有命中。

XAML

<?xml version="1.0" encoding="utf-8"?><ContentPage BackgroundColor="White" xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="ContractorActionSolution.CSA.CSAContentPages.Demo">
<ContentPage.Padding>
    <OnPlatform x:TypeArguments="Thickness">
        <OnPlatform.iOS>0,20,0,0</OnPlatform.iOS>
    </OnPlatform>
</ContentPage.Padding>
<ContentPage.Content>
    <StackLayout Padding="10" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
        <Image x:Name="imgLogo" Source="sisystems_logo.jpg" HorizontalOptions="FillAndExpand" VerticalOptions="Start"/>
        <StackLayout VerticalOptions="CenterAndExpand" Padding="20" HorizontalOptions="FillAndExpand">
            <Label x:Name="lblmsg" TextColor="#F25B63" Text="Error Message"/>
            <Entry x:Name="txtUserName" Placeholder="Email"/>
            <Entry x:Name="txtPassword" Placeholder="Password" IsPassword="True"/>
            <Button  Command="{Binding IncrementCommand}" Text="Continue"/>
            <Label Text="Can't Login ?" TextColor="#F25B63" HorizontalOptions="Center"/>
        </StackLayout>
    </StackLayout>
</ContentPage.Content>

代码

public partial class Demo : ContentPage
{      
    DemoViewModel _myViewModel;
    public Demo ()
    {
        InitializeComponent ();           
    }
    protected override void OnAppearing()
    {
        base.OnAppearing();
        BindingContext = App.Locator.DemoVM;
        _myViewModel = BindingContext as DemoViewModel;
    }
    protected override void OnDisappearing()
    {
        base.OnDisappearing();
        _myViewModel.CleanUP();
    }
}

型号

public class DemoViewModel : BaseViewModel
{      
    private string _name;
    public string Name
    {
        get { return _name; }
        set { Set(() => Name, ref _name, value); }
    }

    private RelayCommand _incrementCommand;
    /// <summary>  
    /// Gets the IncrementCommand.  
    /// </summary>  
    public RelayCommand IncrementCommand
    {
        get
        {
            return _incrementCommand ?? (_incrementCommand = new RelayCommand(
                () =>
                {                        
                }));
        }
    }
    public void CleanUP()
    {
        Name = string.Empty;
    }        
}

我也试过使用 RelayCommand 和 RelayAsyncCommand 都不起作用。

属性绑定工作正常，

我可以使用 string 属性添加条目绑定，但无法使用按钮添加 RelayCommand。

Answer 1

问题可能是处理程序为空，优化实际上在编译后忽略了它。尝试在其中添加任何内容，例如 Debug.WriteLine("Test"); 以查看是否命中断点。

Xamarin 按钮不适用于 mvvm-light Relaycommand

Xamrin Button is not working for mmvm-light Relay Command

xamarin

xamarin.forms

mvvm-light

relaycommand