WPF 设置Combobox背景色 Win7显示正常，win10不显示

Gavin_Y 2019-02-25 03:56:11

界面代码：

<Window x:Class="WpfApplication1Test.MainWindow"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

         xmlns:bh="clr-namespace:WpfApplication1Test"

        Title="MainWindow" Height="350" Width="525">

    <Grid>

        <Grid.RowDefinitions>

            <RowDefinition Height="60"/>

            <RowDefinition Height="60"/>

        </Grid.RowDefinitions>

        <ComboBox Background="Yellow" Grid.Row="0" Width="100" Height="30"/> 

        <ComboBox  bh:ComboboxBrush.DefaultText="请选择科室" Grid.Row="1" Width="200" Height="30"/>

    </Grid>

</Window>

类：

public static class ComboboxBrush

    {

        public static readonly DependencyProperty DefaultTextProperty =

            DependencyProperty.RegisterAttached("DefaultText", typeof(String), typeof(ComboBox), new PropertyMetadata(null));



        public static String GetDefaultText(DependencyObject obj)

        {

            return (String)obj.GetValue(DefaultTextProperty);

        }

        public static void SetDefaultText(DependencyObject obj, String value)

        {

            var combo = (ComboBox)obj;



            RefreshDefaultText(combo, value);



            combo.SelectionChanged += (sender, _) => RefreshDefaultText((ComboBox)sender, GetDefaultText((ComboBox)sender));



            //obj.SetValue(DefaultTextProperty, value);

        }



        static void RefreshDefaultText(ComboBox combo, string text)

        {

            // if item is selected and DefaultText is set

            if (combo.SelectedIndex == -1 && !String.IsNullOrEmpty(text))

            {

                // Show DefaultText

                var visual = new Label()

                {

                    FontStyle = FontStyles.Italic,

                    Content = text,

                    Foreground = Brushes.Gray

                };

                combo.Background = new VisualBrush(visual)

                {

                    Stretch = Stretch.None,

                    AlignmentX = AlignmentX.Left,

                    AlignmentY = AlignmentY.Center,

                    Transform = new TranslateTransform(3, 0)

                };

            }

            else

            {

                // Hide DefaultText

                combo.Background = null;

            }

        }

    }

图片分别为 Win7和Win10效果。
请问各位高人这个问题需要怎么解决

？感谢感谢！！！

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--大白菜-- 2019-09-18

<ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>

把这段改成自己的样式绑定上就好了

楼主后面用这个怎么实现的？
我现在也是遇到这种情况 win7正常 win10就是白的

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weixin_39274932 2019-02-27

谢谢分享谢谢分享谢谢分享谢谢分享

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北京.NET 2019-02-26

你把自定义控件，改成自带控件试一下

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Gavin_Y 2019-02-26

引用 5 楼 qq_15794739 的回复:

RefreshDefaultText 这个函数里，不管怎么样都重新设置了背景颜色， combo.SelectedIndex == -1 && !String.IsNullOrEmpty(text) 这时候改成了灰色否则的时候清空了颜色 combo.Background = null;

灰色是水印的字体颜色是灰色，我是想用这个控件来作为背景来显示的。win7上都能正常显示，win10就显示不了。

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Gavin_Y 2019-02-26

引用 6 楼 qq_15794739 的回复:

再说你绑定颜色干嘛在后台绑定，直接在样式里面绑不就完了，百度搜一下样式触发器 Trigger

我是想实现水印的效果。背景为黄色的combobox是我测试用的。想验证下，单纯设置背景颜色在win10下是否可以正常显示的。

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北京.NET 2019-02-26

再说你绑定颜色干嘛在后台绑定，直接在样式里面绑不就完了，百度搜一下样式触发器 Trigger

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北京.NET 2019-02-26

RefreshDefaultText 这个函数里，不管怎么样都重新设置了背景颜色，

combo.SelectedIndex == -1 && !String.IsNullOrEmpty(text) 这时候改成了灰色

否则的时候清空了颜色
combo.Background = null;

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Gavin_Y 2019-02-26

引用 3 楼 assky124 的回复:

用Blend 右键编辑控件模板，看看都是啥，然后模板改掉生成新的Style

<Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">
            <Setter Property="FocusVisualStyle" Value="{StaticResource ComboBoxFocusVisual}"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
            <Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/>
            <Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/>
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
            <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
            <Setter Property="Padding" Value="4,3"/>
            <Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
            <Setter Property="ScrollViewer.PanningMode" Value="Both"/>
            <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ComboBox}">
                        <Grid x:Name="MainGrid" SnapsToDevicePixels="true">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*"/>
                                <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
                            </Grid.ColumnDefinitions>
                            <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                                <Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}">
                                    <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
                                        <ScrollViewer x:Name="DropDownScrollViewer">
                                            <Grid RenderOptions.ClearTypeHint="Enabled">
                                                <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                                    <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>
                                                </Canvas>
                                                <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                            </Grid>
                                        </ScrollViewer>
                                    </Border>
                                </Themes:SystemDropShadowChrome>
                            </Popup>
                            <ToggleButton BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxReadonlyToggleButton}"/>
                            <ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                                <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
                                <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>
                            </Trigger>
                            <Trigger Property="HasItems" Value="false">
                                <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
                            </Trigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                                <Setter Property="Background" Value="#FFF4F4F4"/>
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsGrouping" Value="true"/>
                                    <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                            </MultiTrigger>
                            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
                                <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
                                <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <Trigger Property="IsEditable" Value="true">
                    <Setter Property="BorderBrush" Value="{StaticResource TextBoxBorder}"/>
                    <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>
                    <Setter Property="IsTabStop" Value="false"/>
                    <Setter Property="Padding" Value="3"/>
                    <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
                </Trigger>
            </Style.Triggers>
        </Style>

是把Background改成动态分配的么？

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assky124 2019-02-26

用Blend 右键编辑控件模板，看看都是啥，然后模板改掉生成新的Style

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a156191117 2019-02-26

不知所云的路过。

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Gavin_Y 2019-02-26

引用 10 楼 assky124 的回复:

<ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/> 把这段改成自己的样式绑定上就好了

好的，感谢感谢。由于时间紧我用来有水印功能的combobox来实现的。

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assky124 2019-02-26

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Gavin_Y 2019-02-25