如何根据其属性更改自定义控件的背景颜色 [英] How to change custom control's background color based on its property

问题描述

我有一个简单的自定义控件，它向用户显示一条消息（类似于浏览器的信息栏）。

I have simple custom control that shows a message to user (something like browser's Info bar).

我添加了一个布尔型依赖属性，用于指示错误消息。如果设置了flag，则控件的背景颜色应为红色，否则为黄色。

I have added a Boolean Dependency Property that indicate an error message. If flag is set the background color of control should be red otherwise yellow.

以下是控件的样式（在Themes\Generic.xaml中）：

Here is style for the control(in Themes\Generic.xaml):

<Style TargetType="{x:Type local:InfoBar}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:InfoBar}">
                <ControlTemplate.Triggers>
                    <Trigger Property="IsError" Value="True" >
                             <Setter Property="Background" Value="LightPink" />
                    </Trigger>
                    <Trigger Property="IsError" Value="False" >
                             <Setter Property="Background" Value="LightYellow" />
                    </Trigger>                  
                </ControlTemplate.Triggers>

                <Grid Margin="4,0,4,0">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="auto" />
                    </Grid.ColumnDefinitions>
                    <TextBlock Text="{TemplateBinding Message}" Padding="5" FontWeight="Normal" TextWrapping="Wrap" Grid.Column="0"/>
                    <Button x:Name="PART_CloseButton" Grid.Column="1" VerticalAlignment="Top"  >
                        <Button.Template>
                            <ControlTemplate>
                                <Border HorizontalAlignment="Center" VerticalAlignment="Center" BorderBrush="Transparent">
                                    <Image Height="16" Width="16" Source="/QOffice.Common.Controls;component/Images/icons/Close.png"  />
                                </Border>
                            </ControlTemplate>
                        </Button.Template>
                    </Button>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

这里是控件本身：

[TemplatePart(Name = PART_CloseButton, Type = typeof(ButtonBase))]
public class InfoBar : Control
{

    private const string PART_CloseButton = "PART_CloseButton";

    static InfoBar()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(InfoBar), new FrameworkPropertyMetadata(typeof(InfoBar)));

    }

    #region CloseButton

    private ButtonBase _closeButton;
    /// <summary>
    /// Gets or sets the CloseButton template part.
    /// </summary>
    private ButtonBase CloseButton
    {
        get
        {
            return _closeButton;
        }
        set
        {
            if (_closeButton != null)
            {
                _closeButton.Click -= OnButtonClick;
            }

            _closeButton = value;

            if (_closeButton != null)
            {
                _closeButton.Click += OnButtonClick;
            }
        }
    }

    private void OnButtonClick(object sender, RoutedEventArgs e)
    {
        this.Visibility = System.Windows.Visibility.Collapsed;
    }


    #endregion 


    public override void OnApplyTemplate()
    {
        CloseButton = GetTemplateChild(PART_CloseButton) as ButtonBase;


    }


    #region DependencyProperty Message of InfoBar

    public string Message
    {
        get { return (string)GetValue(MessageProperty); }
        set { SetValue(MessageProperty, value); }
    }

    public static readonly DependencyProperty MessageProperty =
        DependencyProperty.Register("Message", typeof(string), typeof(InfoBar),
                new UIPropertyMetadata());

    #endregion


    #region DependencyProperty IsError of InfoBar

    public bool IsError
    {
        get { return (bool)GetValue(IsErrorProperty); }
        set { SetValue(IsErrorProperty, value); }
    }

    public static readonly DependencyProperty IsErrorProperty =
        DependencyProperty.Register("IsError", typeof(bool), typeof(InfoBar),
                new UIPropertyMetadata());

    #endregion





}

如您所见，我定义了一个属性IsError和一个用于设置控件背景的触发器。

As you can see I have defined a property IsError and a trigger to set the background of the control.

但是背景始终是透明的。

But the background is always transparent. Other than that the control if functional.

有什么问题吗？

推荐答案

即使我手动添加背景色，您的自定义控件似乎也无法正确设置背景色。我不确定为什么会这样，希望有人能详细说明。我确实通过使用以下方式更改了样式中的Grid的颜色来解决了您的问题：

It seems that your Custom Control is not setting Background Color properly even if I add Background color manually. I am not sure why this is, hopefully someone can elaborate. I did fix your issue though by changing the color of the Grid in your style using:

<Grid.Style>
    <Style TargetType="{x:Type Grid}">
        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:InfoBar}}, Path=IsError}" Value="True">
                <Setter Property="Background" Value="LightPink" />
            </DataTrigger>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:InfoBar}}, Path=IsError}" Value="False">
                <Setter Property="Background" Value="LightYellow" />
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Grid.Style>

这会基于InfoBar控件中的IsError值触发网格的背景颜色。

This triggers the background color of the grid based on the IsError value in your InfoBar control.

这篇关于如何根据其属性更改自定义控件的背景颜色的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！