当 Entry 字段不可见时，如何在 Xamarin 表单中隐藏错误标签? [英] How to hide the error label in Xamarin forms, when the Entry field is not visible?

问题描述

我正在尝试创建一个有验证错误的登录页面.现在，如果 Entry 字段不可见，也会出现验证错误.当输入字段不可见时，如何隐藏错误标签?如下图: PIN 输入字段在登录页面上不可见，但错误信息:Pin is required，突出显示.请问有人可以提出解决方法吗?

I am trying to create a Login page that has validation errors. Right now the validation errors are also appearing if the Entry field is not visible. How would I hide the error labels, when the entry field is not visible? As shown below: The PIN entry field is invisible on the login page but the error message: Pin is required, highlights. Please could anyone suggest a workaround?

推荐答案

同意 Jason 的意见.您可以使用数据绑定将标签的 IsVisible 绑定到视图模型中的属性.

Agree with Jason . You can use the data-binding to binding the IsVisible of labelto the property in your viewmodel .

<Label Text="Pin is requored!"  TextColor="Red"  HorizontalTextAlignment="Center" IsVisible="{Binding isVisible}"/>

<Button Text="sign in" BackgroundColor="Red" TextColor="White" Command="{Binding ClickCommand}"  WidthRequest="200" />

在您的视图模型中

public class YourViewModel: INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    public ICammand ClickCommand {get; set;}


    private bool isvisible;

    public bool isVisible
    {
     get
     {
        return isvisible;
     }

     set
     {
      if (isvisible!= value)
      {
        isvisible= value;
        NotifyPropertyChanged();
      }
    }


    public YourViewModel()
    {
        //... 
        isVisible = true; //show the label in default
         
        ClickCommand = new Command(() =>
        {
           if(xxx)
           {
              isVisible =false;
           }
           
           else
           { 
              isVisible =true;
           }
        }) ;

    }

}

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