C# Xamarin表单，快速按下按钮将打开2倍于相同窗口的窗口

当我单击重定向到新窗口的图标时，它会打开相同的视图两次。我不知道如何处理它，只打开一个视图

示例xaml按钮

<local:AnimatedImage Grid.Column="2" Source="googlemap_view_search.png"
                    HorizontalOptions="Center" VerticalOptions="Center" Margin="16,0">
                <Image.GestureRecognizers>
                    <TapGestureRecognizer Command="{Binding SearchCommand}" />
                </Image.GestureRecognizers>
            </local:AnimatedImage>

---

问题是，当您在执行搜索命令之前等待动画时，没有任何东西阻止用户再次启动该命令。您可以添加一个布尔变量，该变量在输入命令时设置为

true

，如果命令已在执行，则忽略第二次用户点击

private ICommand TransitionCommand
{
    get
    {
        bool isExecuting = false;
        return new Command(async () =>
        {
            if(isExecuting) return;
            isExecuting = true
            try
            {
                this.AnchorX = 0.48;
                this.AnchorY = 0.48;
                await this.ScaleTo(MAGNIFICATION_VALUE, 50, Easing.Linear);
                await Task.Delay(ANIMATED_TIME);
                await this.ScaleTo(INITIAL_VALUE, 50, Easing.Linear);
                if (Command != null)
                {
                    Command.Execute(CommandParameter);
                }
             }
             finally 
             {
                  isExecuting = false;
             }
        });
    }
}

---

Xamarin

Command

有一个方法，可以根据您的业务逻辑来阻止命令的执行

public ICommand SearchCommand {get; private set; }

bool _canSearch = true;
public bool CanSearch 
{ 
    get { return _canSearch; } 
    private set { 
        _canSearch = value;
        ((Command)SearchCommand).ChangeCanExecute(); 
    }
}

public SearchPageViewModel()
{
    SearchCommand = new Command(() => DoSearchStuff(), () => CanSearch)
}

void DoSearchStuff()
{
    CanSearch = false;
    // long searching stuff
    CanSearch = true;
}

---

希望这对每次调用getter时返回

新命令有所帮助？
private ICommand TransitionCommand
{
    get
    {
        bool isExecuting = false;
        return new Command(async () =>
        {
            if(isExecuting) return;
            isExecuting = true
            try
            {
                this.AnchorX = 0.48;
                this.AnchorY = 0.48;
                await this.ScaleTo(MAGNIFICATION_VALUE, 50, Easing.Linear);
                await Task.Delay(ANIMATED_TIME);
                await this.ScaleTo(INITIAL_VALUE, 50, Easing.Linear);
                if (Command != null)
                {
                    Command.Execute(CommandParameter);
                }
             }
             finally 
             {
                  isExecuting = false;
             }
        });
    }
}

public ICommand SearchCommand {get; private set; }

bool _canSearch = true;
public bool CanSearch 
{ 
    get { return _canSearch; } 
    private set { 
        _canSearch = value;
        ((Command)SearchCommand).ChangeCanExecute(); 
    }
}

public SearchPageViewModel()
{
    SearchCommand = new Command(() => DoSearchStuff(), () => CanSearch)
}

void DoSearchStuff()
{
    CanSearch = false;
    // long searching stuff
    CanSearch = true;
}