Question

如何设置Label（Content）的L_Watermark属性？我尝试了不同的方法但没有任何作用通常要设置一个关于他的名字的元素的属性，但在这里它不起作用。我希望在CodeBehind中执行此操作，或者使用Databinding执行依赖项属性

我的UserControl的XAML：

<StackPanel Orientation="Horizontal" Width="155">
    <TextBox x:Name="TB_Date" LostFocus="TB_Date_LostFocus" KeyDown="TB_Date_KeyDown" BorderThickness="0" VerticalContentAlignment="Center" Width="125" Height="24">
        <TextBox.Style>
            <Style TargetType="TextBox" xmlns:sys="clr-namespace:System;assembly=mscorlib">
                <Style.Resources>
                    <VisualBrush x:Name="VisuBrush" x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
                        <VisualBrush.Visual>
                            <Label x:Name="L_Watermark" Content="{Binding Watermark, UpdateSourceTrigger=PropertyChanged, Mode=OneWay, FallbackValue=Date}" Foreground="LightGray" />
                        </VisualBrush.Visual>
                    </VisualBrush>
                </Style.Resources>
                <Style.Triggers>
                    <Trigger Property="Text" Value="{x:Static sys:String.Empty}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="Text" Value="{x:Null}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="True">
                        <Setter Property="Background" Value="White" />
                    </Trigger>
                </Style.Triggers>
            </Style>
        </TextBox.Style>
    </TextBox>
    <DatePicker Name="DP_Date" Focusable="False" BorderBrush="{x:Null}" SelectedDateChanged="DP_Date_SelectedDateChanged" Width="30" FirstDayOfWeek="Monday" Height="24"/>
</StackPanel>

以下是我想要设置Content标签的L_Watermark属性的事件处理程序

 private void Initialize(object sender, EventArgs e)
    {
        if (HasStartTime)
        {
            TB_Date.Text = DateTime.Now.ToLongDateString(); 
        }
        Debug.WriteLine(Watermark);
    }

与Text中的TB_Date一样，我尝试使用L_Watermark.Content = Watermark

我也尝试过Databinding，如：

<Label x:Name="L_Watermark" Content="{Binding Watermark, UpdateSourceTrigger=PropertyChanged, Mode=OneWay, FallbackValue=Date}" Foreground="LightGray" />

我的UserControl中还有两个依赖项属性：

public bool HasStartTime
{
    get { return (bool)GetValue(HasStartTimeProperty); }
    set
    {
        SetValue(HasStartTimeProperty, value);
        OnPropertyChanged();
    }
}

// Using a DependencyProperty as the backing store for HasStartTime.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty HasStartTimeProperty =
    DependencyProperty.Register("HasStartTime", typeof(bool), typeof(AdvancedDatePicker), new PropertyMetadata(false));

public string Watermark
{
    get { return (string)GetValue(WatermarkProperty); }
    set
    {
        SetValue(WatermarkProperty, value);
        OnPropertyChanged();
    }
}

// Using a DependencyProperty as the backing store for Watermark.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty WatermarkProperty =
    DependencyProperty.Register("Watermark", typeof(string), typeof(AdvancedDatePicker), new PropertyMetadata("Datum"));

样式中的元素的WPF Set属性（Visual.Brush）

0 个答案: