c# – 文本框有时会丢失光标

我创建了一个自定义水印文本框,从文本框扩展.其控制模板如下所示.

<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate targettype="{x:Type controls:WaterMarkTextBox}">
            <ControlTemplate.Resources>
                <Storyboard x:Key="Storyboard1">
                    <ThicknessAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.Margin)"
                                                      Storyboard.TargetName="PART_FieldTextBlock">
                        <SplineThicknessKeyFrame KeyTime="0:0:0.15"
                                                 Value="0,10,0" />
                    </ThicknessAnimationUsingKeyFrames>
                </Storyboard>
                <Storyboard x:Key="Storyboard2">
                    <ThicknessAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.Margin)"
                                                      Storyboard.TargetName="PART_FieldTextBlock">
                        <SplineThicknessKeyFrame KeyTime="0:0:0.25"
                                                 Value="0,-500,0" />
                    </ThicknessAnimationUsingKeyFrames>
                </Storyboard>
            </ControlTemplate.Resources>
            <Grid x:Name="PART_GridControl"
                  ClipToBounds="True"
                  Height="{TemplateBinding Height}"
                  Width="{TemplateBinding Width}">
                <TextBlock x:Name="PART_PlaceHolderTextBlock"
                           Style="{StaticResource SWMLightTextBlockStyle}"
                           Foreground="#BDBBBB"
                           FontSize="{StaticResource SmallFontSize}"
                           Text="{TemplateBinding PlaceHolderText}"
                           VerticalAlignment="Center"
                           Margin="20,0" />
                <Border Name="border"
                        CornerRadius="0"
                        Padding="2"
                        BorderThickness="1"
                        BorderBrush="DeepSkyBlue">
                    <ScrollViewer x:Name="PART_ContentHost"/>
                </Border>
                <TextBlock x:Name="PART_FieldTextBlock"
                           HorizontalAlignment="Right"
                           Foreground="#BDBBBB"
                           Margin="0,0"
                           Style="{StaticResource SWMLightTextBlockStyle}"
                           FontSize="{StaticResource SmallFontSize}"
                           textwrapping="Wrap"
                           Text="{TemplateBinding FieldText}"
                           VerticalAlignment="Center" />
            </Grid>
        </ControlTemplate>
    </Setter.Value>
</Setter>

但是当输入文本框进入一个没有光标的情况但是我们可以输入它的概率是1/2字符.我想知道它是如何发生的.任何人都知道它是如何发生的？

解决方法

你可以做两件事.第一个是覆盖SystemParameters属性使用反射像这样

void LocallydisableMouseVanish()
    {
        foreach (var field in typeof(SystemParameters).GetFields(BindingFlags.NonPublic|BindingFlags.Static))
            if (field.Name.Contains("mouseVanish"))
                field.SetValue(null,false);
    }

在您的控制焦点上调用此方法.

如果这不起作用意味着你可以试试这样的东西覆盖Caret的风格就像这样

<Setter Property="Template">
        <Setter.Value>
            <ControlTemplate targettype="{x:Type controls:WaterMarkTextBox}">
                <ControlTemplate.Resources>
                    <Storyboard x:Key="Storyboard1">
                        <ThicknessAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.Margin)"
                                                          Storyboard.TargetName="PART_FieldTextBlock">
                            <SplineThicknessKeyFrame KeyTime="0:0:0.15"
                                                     Value="0,0" />
                        </ThicknessAnimationUsingKeyFrames>
                    </Storyboard>
                    <Storyboard x:Key="Storyboard2">
                        <ThicknessAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.Margin)"
                                                          Storyboard.TargetName="PART_FieldTextBlock">
                            <SplineThicknessKeyFrame KeyTime="0:0:0.25"
                                                     Value="0,0" />
                        </ThicknessAnimationUsingKeyFrames>
                    </Storyboard>
                </ControlTemplate.Resources>
                <Grid x:Name="PART_GridControl"
                      ClipToBounds="True"
                      Height="{TemplateBinding Height}"
                      Width="{TemplateBinding Width}">
                    <TextBlock x:Name="PART_PlaceHolderTextBlock"
                               Style="{StaticResource SWMLightTextBlockStyle}"
                               Foreground="#BDBBBB"
                               FontSize="{StaticResource SmallFontSize}"
                               Text="{TemplateBinding PlaceHolderText}"
                               VerticalAlignment="Center"
                               Margin="20,0" />
                    <Border Name="border"
                            CornerRadius="0"
                            Padding="2"
                            BorderThickness="1"
                            BorderBrush="DeepSkyBlue">
                        <ScrollViewer x:Name="PART_ContentHost" />
                    </Border>
                    <TextBlock x:Name="PART_FieldTextBlock"
                               HorizontalAlignment="Right"
                               Foreground="#BDBBBB"
                               Margin="0,0"
                               Style="{StaticResource SWMLightTextBlockStyle}"
                               FontSize="{StaticResource SmallFontSize}"
                               textwrapping="Wrap"
                               Text="{TemplateBinding FieldText}"
                               VerticalAlignment="Center" />
                    <Canvas>
                        <Border x:Name="PART_Caret"
                                Visibility="Collapsed"
                                Canvas.Left="0"
                                Canvas.Top="0"
                                Width="5"
                                Height="25"
                                Background="Black"
                                BorderThickness="1">
                            <Border.Triggers>
                                <EventTrigger RoutedEvent="Border.Loaded">
                                    <BeginStoryboard>
                                        <Storyboard  x:Name="CaretStoryBoard"
                                                     RepeatBehavior="Forever">
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="Background.Color"
                                                                          Duration="0:0:0:1"
                                                                          FillBehavior="HoldEnd">
                                                <ColorAnimationUsingKeyFrames.KeyFrames>
                                                    <discreteColorKeyFrame KeyTime="0:0:0.750"
                                                                           Value="Transparent" />
                                                    <discreteColorKeyFrame KeyTime="0:0:0.000"
                                                                           Value="Black" />
                                                </ColorAnimationUsingKeyFrames.KeyFrames>
                                            </ColorAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </EventTrigger>
                            </Border.Triggers>
                        </Border>
                    </Canvas>
                </Grid>

            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Setter Property="CaretBrush "
            Value="Transparent" />

并在您的控制代码中添加此项

public override void OnApplyTemplate()
    {
        this.border = this.GetTemplateChild("PART_Caret") as Border;
        base.OnApplyTemplate();
    }

并添加此方法

private void MoveCustomCaret()
    {
        var caretLocation = this.GetRectFromCharacterIndex(this.CaretIndex).Location;

        if (!double.IsInfinity(caretLocation.X))
        {
            Canvas.SetLeft(border,caretLocation.X);
        }

        if (!double.IsInfinity(caretLocation.Y))
        {
            Canvas.SetTop(border,caretLocation.Y);
        }
    }

最后调用此方法并设置边框的可见性

private void SWMTextBox_GotFocus(object sender,RoutedEventArgs e)
    {
        MoveCustomCaret();
        border.Visibility = Visibility.Visible;
    }

也在TextChangedEvent中

private void CustomTextBox_TextChanged(object sender,TextChangedEventArgs e)
    {
        MoveCustomCaret();
    }

并隐藏了Lost_Focus_Event中的可见性

private void SWMTextBox_LostFocus(object sender,RoutedEventArgs e)
    {
        border.Visibility = Visibility.Hidden;
    }