C# 如何使用触发器更改文本块的可见性？_C#_Wpf_Xaml_Triggers

C# 如何使用触发器更改文本块的可见性？

c# wpf xaml triggers

C# 如何使用触发器更改文本块的可见性？,c#,wpf,xaml,triggers,C#,Wpf,Xaml,Triggers,当我试图编译以下代码时，我得到一个错误，“可见性”成员无效，因为它没有限定的类型名。当Status=off时，我必须更改什么才能使文本块消失 XAML: <Window x:Class="TestTrigger123345.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xa

当我试图编译以下代码时，我得到一个错误，“可见性”成员无效，因为它没有限定的类型名。

当Status=off时，我必须更改什么才能使文本块消失

XAML:

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <TextBlock Text="This is a sentence.">
            <TextBlock.Triggers>
                <Trigger Property="{Binding Status}" Value="off">
                    <Setter Property="Visibility" Value="Collapsed"/>
                </Trigger>
            </TextBlock.Triggers>
        </TextBlock>
        <TextBlock Text="{Binding Status}"/>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        public string Status { get; set; }

    }
}

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel HorizontalAlignment="Left">
        <TextBlock Text="{Binding Status}">
            <TextBlock.Triggers>
                <DataTrigger Binding="{Binding Status}" Value="off">
                    <Setter Property="TextBlock.Background" Value="Tan"/>
                </DataTrigger>
            </TextBlock.Triggers>
        </TextBlock>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        #region DependencyProperty: Status
        public string Status
        {
            get
            {
                return (string)GetValue(StatusProperty);
            }
            set
            {
                SetValue(StatusProperty, value);
            }
        }

        public static readonly DependencyProperty StatusProperty =
            DependencyProperty.Register("Status", typeof(string), typeof(Window1),
            new FrameworkPropertyMetadata());
        #endregion


    }
}

using System.ComponentModel;

namespace TestTrigger123345
{
    class WindowViewModel
    {
        #region ViewModelProperty: Status
        private string _status;
        public string Status
        {
            get
            {
                return _status;
            }

            set
            {
                _status = value;
                OnPropertyChanged("Status");
            }
        }
        #endregion

        #region PropertChanged Block
        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string property)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(property));
            }
        }
        #endregion
    }
}

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            WindowViewModel windowViewModel = new WindowViewModel();
            windowViewModel.Status = "off";
            DataContext = windowViewModel;
        }

    }
}

我更改为DataTrigger和Dependency属性，它得到了相同的错误：

XAML:

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <TextBlock Text="This is a sentence.">
            <TextBlock.Triggers>
                <Trigger Property="{Binding Status}" Value="off">
                    <Setter Property="Visibility" Value="Collapsed"/>
                </Trigger>
            </TextBlock.Triggers>
        </TextBlock>
        <TextBlock Text="{Binding Status}"/>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        public string Status { get; set; }

    }
}

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel HorizontalAlignment="Left">
        <TextBlock Text="{Binding Status}">
            <TextBlock.Triggers>
                <DataTrigger Binding="{Binding Status}" Value="off">
                    <Setter Property="TextBlock.Background" Value="Tan"/>
                </DataTrigger>
            </TextBlock.Triggers>
        </TextBlock>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        #region DependencyProperty: Status
        public string Status
        {
            get
            {
                return (string)GetValue(StatusProperty);
            }
            set
            {
                SetValue(StatusProperty, value);
            }
        }

        public static readonly DependencyProperty StatusProperty =
            DependencyProperty.Register("Status", typeof(string), typeof(Window1),
            new FrameworkPropertyMetadata());
        #endregion


    }
}

using System.ComponentModel;

namespace TestTrigger123345
{
    class WindowViewModel
    {
        #region ViewModelProperty: Status
        private string _status;
        public string Status
        {
            get
            {
                return _status;
            }

            set
            {
                _status = value;
                OnPropertyChanged("Status");
            }
        }
        #endregion

        #region PropertChanged Block
        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string property)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(property));
            }
        }
        #endregion
    }
}

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            WindowViewModel windowViewModel = new WindowViewModel();
            windowViewModel.Status = "off";
            DataContext = windowViewModel;
        }

    }
}

我用一个属性状态为实现INotifyPropertyChanged的ViewModel对此进行了重新命名，它得到了相同的错误：

WindowViewModel.cs:

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <TextBlock Text="This is a sentence.">
            <TextBlock.Triggers>
                <Trigger Property="{Binding Status}" Value="off">
                    <Setter Property="Visibility" Value="Collapsed"/>
                </Trigger>
            </TextBlock.Triggers>
        </TextBlock>
        <TextBlock Text="{Binding Status}"/>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        public string Status { get; set; }

    }
}

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel HorizontalAlignment="Left">
        <TextBlock Text="{Binding Status}">
            <TextBlock.Triggers>
                <DataTrigger Binding="{Binding Status}" Value="off">
                    <Setter Property="TextBlock.Background" Value="Tan"/>
                </DataTrigger>
            </TextBlock.Triggers>
        </TextBlock>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        #region DependencyProperty: Status
        public string Status
        {
            get
            {
                return (string)GetValue(StatusProperty);
            }
            set
            {
                SetValue(StatusProperty, value);
            }
        }

        public static readonly DependencyProperty StatusProperty =
            DependencyProperty.Register("Status", typeof(string), typeof(Window1),
            new FrameworkPropertyMetadata());
        #endregion


    }
}

using System.ComponentModel;

namespace TestTrigger123345
{
    class WindowViewModel
    {
        #region ViewModelProperty: Status
        private string _status;
        public string Status
        {
            get
            {
                return _status;
            }

            set
            {
                _status = value;
                OnPropertyChanged("Status");
            }
        }
        #endregion

        #region PropertChanged Block
        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string property)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(property));
            }
        }
        #endregion
    }
}

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            WindowViewModel windowViewModel = new WindowViewModel();
            windowViewModel.Status = "off";
            DataContext = windowViewModel;
        }

    }
}

代码隐藏：

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <TextBlock Text="This is a sentence.">
            <TextBlock.Triggers>
                <Trigger Property="{Binding Status}" Value="off">
                    <Setter Property="Visibility" Value="Collapsed"/>
                </Trigger>
            </TextBlock.Triggers>
        </TextBlock>
        <TextBlock Text="{Binding Status}"/>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        public string Status { get; set; }

    }
}

<Window x:Class="TestTrigger123345.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel HorizontalAlignment="Left">
        <TextBlock Text="{Binding Status}">
            <TextBlock.Triggers>
                <DataTrigger Binding="{Binding Status}" Value="off">
                    <Setter Property="TextBlock.Background" Value="Tan"/>
                </DataTrigger>
            </TextBlock.Triggers>
        </TextBlock>
    </StackPanel>
</Window>

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = this;
            Status = "off";
        }

        #region DependencyProperty: Status
        public string Status
        {
            get
            {
                return (string)GetValue(StatusProperty);
            }
            set
            {
                SetValue(StatusProperty, value);
            }
        }

        public static readonly DependencyProperty StatusProperty =
            DependencyProperty.Register("Status", typeof(string), typeof(Window1),
            new FrameworkPropertyMetadata());
        #endregion


    }
}

using System.ComponentModel;

namespace TestTrigger123345
{
    class WindowViewModel
    {
        #region ViewModelProperty: Status
        private string _status;
        public string Status
        {
            get
            {
                return _status;
            }

            set
            {
                _status = value;
                OnPropertyChanged("Status");
            }
        }
        #endregion

        #region PropertChanged Block
        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string property)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(property));
            }
        }
        #endregion
    }
}

using System.Windows;

namespace TestTrigger123345
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            WindowViewModel windowViewModel = new WindowViewModel();
            windowViewModel.Status = "off";
            DataContext = windowViewModel;
        }

    }
}

当然有一种方法可以通过触发器来实现这一点。

也许您需要实现INotifyPropertyChanged并在状态更改时引发PropertyChange

不使用触发器，您可以在可见性和状态字符串之间使用转换器。

对于绑定，可以使用DataTrigger；对于属性，可以使用trigger。。还要确保Status属性通知；）将其作为依赖项属性或使用INotifyPropertyChanged接口

您需要指定应设置可见性的类型

<Setter Property="FrameworkElement.Visibility" Value="Visible"/>

元素的触发器仅支持EventTrigger，因此不能使用属性触发器（Trigger）。查看FrameworkElement.Triggers属性。

尝试以下操作：

<PasswordBox Name="pbxPassword" />
<TextBox Text="{Binding Password,
                        ElementName=pbxPassword,
                        UpdateSourceTrigger=PropertyChanged}">
    <TextBox.Style>
        <Style TargetType="TextBox">
            <Setter Property="Visibility" Value="Hidden" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding IsChecked, ElementName=chbShowPassword}" Value="True">
                    <Setter Property="Visibility" Value="Visible" />
                </DataTrigger>                  
            </Style.Triggers>
        </Style>
    </TextBox.Style>
</TextBox>
<CheckBox Name="chbShowPassword">
    Show password
</CheckBox>


显示密码

它在DataTrigger和Dependency属性（上面发布的代码）上得到了相同的错误。我的代码似乎与那篇文章实现的一样，只是DataTrigger，绑定到属性，只是他使用了一种样式，但这不应该有任何区别。我还用ViewModel（上面的代码）重新实现了这一点，它得到了相同的错误。一定是XAML的问题，我真的需要EventTrigger吗？所有代码示例（如您提供的示例）都只是使用DataTrigger并绑定到他们要检查的属性。嘿，Edward，请参见您的另一个问题的答案：）这样我的转换器将获取字符串（状态）并返回属性可见性？还是说返回整个元素？这将如何在代码中实现？我还使用ViewModel（上面的代码）重新实现了这一点，它得到了相同的错误。为什么有时在没有类型名称的情况下可以工作？喜欢这是令人困惑的…因为Microsoft，这就是原因。

DependencyObject

可以在父类上用相同名称中的一个“隐藏”一个

dependencProperty

，但它们需要在字典中有唯一的名称。在本例中，“FrameworkElement.”是字典键的一部分，您需要引用字典键。