WPF中ToolTip的自定義

ToolTip或者PopUp這個控件在做界面時會經常用到。如何對ToolTip進行自定義呢？

1.首先自定義tooltip的controlTemplate，完全清除系統默認效果， 如下：

<ControlTemplate x:Key ="TooltipTemplate" TargetType="ToolTip">
              <ContentPresenter x :Name="contentPresenter" Height="{TemplateBinding Height }" Width="{ TemplateBinding Width}" ContentTemplate="{TemplateBinding ContentTemplate }" ></ContentPresenter>
          </ControlTemplate>

2.自定義tooltip的contentTemplate， 這樣可以專注於tooltip的界面呈現， 而不關心tooltip要顯示的字符串， 如下：

 

<Style x :Key="ToolTipStyle" TargetType="ToolTip">
                <Setter Property ="IsOpen" Value="False">
                </Setter>

                <Setter Property ="ContentTemplate">
                    <Setter.Value>
                        <DataTemplate>
                            <Border x :Name="errorBorder" Background="#CC595959" BorderBrush="#99000000" BorderThickness="1" CornerRadius ="3" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin ="0" MaxWidth="320">
                                <Border.Effect>
                                    <DropShadowEffect BlurRadius ="4" ShadowDepth="0"/>
                                </Border.Effect>
                                <Grid>
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width ="Auto"/>
                                        <ColumnDefinition Width ="*"/>
                                    </Grid.ColumnDefinitions>
                                    <Border Margin ="16,16,8,16" VerticalAlignment="Top">
                                        <Path x :Name="path1" Grid.ColumnSpan="1" Data="M9.0789473,12.870737 L10.927632,12.870737 10.927632,14.5 9.0789473,14.5 z M9.0000001,5.9999999 L11,5.9999999 11,7.994543 10.526316,12.308322 9.4802633,12.308322 9.0000001,7.994543 z M9.9647158,1.8074455 C9.5912184,1.7923756 9.2860216,2.1402843 9.2860216,2.1402845 9.2860216,2.1402843 2.5977592,14.8926 2.2227221,15.46075 1.8476844,16.028899 2.5562553,16.218284 2.5562553,16.218284 2.5562553,16.218284 16.2035,16.218284 17.18278,16.218284 18.162063,16.218284 17.870029,15.460751 17.870029,15.460751 17.870029,15.460751 11.056506,2.8352754 10.494117,2.1197443 10.31837,1.8961406 10.134488,1.8142953 9.9647158,1.8074455 z M9.9331295,0.00021409988 C10.317457,0.0076069832 10.762559,0.20740509 11.244278,0.77299643 12.785778,2.5828881 19.97391,16.249695 19.97391,16.249695 19.97391,16.249695 20.318179,17.954408 18.505573,17.985971 16.692966,18.017535 1.5982747,17.985971 1.5982747,17.985971 1.5982747,17.985971 -0.27740097,18.206807 0.03512764,16.028899 0.3476572,13.850991 8.5362361,0.89893103 8.536236,0.8989315 8.5362361,0.89893103 9.0876089,-0.016049385 9.9331295,0.00021409988 z" Height="17" Stretch="Fill" Width="20" Visibility="Visible" Fill ="Red"/>
                                    </Border>
                                    <TextBlock x :Name="textBlock" Text="{TemplateBinding Content }" Margin="0,14,10,14" FontSize="14" Grid.Column ="1" TextWrapping="Wrap" Foreground="Red"/>
                                </Grid>
                            </Border>
                        </DataTemplate>
                    </Setter.Value>
                </Setter>

                <Style.Triggers>
                    <Trigger Property ="IsOpen" Value="True">
                        <Trigger.EnterActions>
                            <BeginStoryboard>
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Duration="0:0:3">
                                        <DiscreteObjectKeyFrame KeyTime ="0:0:0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <Visibility> Visible</Visibility >
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                        <DiscreteObjectKeyFrame KeyTime ="0:0:3">
                                           <DiscreteObjectKeyFrame.Value>
                                                <Visibility> Hidden</Visibility >
                                           </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </BeginStoryboard>
                        </Trigger.EnterActions>
                    </Trigger>
                </Style.Triggers>
            </Style>

3.應用Tooltip的style，如下：

<Button Content ="TestButton">
        < Button.ToolTip>
            < ToolTip Style ="{ DynamicResource ToolTipStyle}" Content="This is a button"></ ToolTip >
        </ Button.ToolTip>
    </ Button>

4.以上style使用時的注意事項：

因爲Animation的設置值優先於本地設置值，所以會出現ToolTip在動畫結束時永遠隱藏。

因此在需要打開tooltip時，首先要在動畫開始時設置Visibility爲Visible，第二要觸發IsOpen=True則必須先IsOpen=False， 因爲在Tooltip隱藏後並沒有設置IsOpen=False。

代碼如下：

_toolTip.Style = ToolTipStyle;
                        _toolTip.PlacementTarget = this.AssociatedObject;
                        _toolTip.Placement = PlacementMode.Bottom;
                        _toolTip.Content = toolTipText;

                        //must set false first to trigger storyboard
                        _toolTip.IsOpen = false;
                        _toolTip.IsOpen = true;
                        _toolTip.StaysOpen = false;

5.ToolTip的bug

對於ToolTip的顯示延遲、顯示時間長度、是否保持顯示、顯示時的位置等等，通用的做法都是通過ToolTipService來進行統一設置。比如：

ToolTipService.InitialShowDelay="1000"
ToolTipService.ShowDuration="7000"
ToolTipService.BetweenShowDelay="2000"
ToolTipService.Placement="Right"
ToolTipService.PlacementRectangle="50,0,0,0"
ToolTipService.HorizontalOffset="10"
ToolTipService.VerticalOffset="20"
ToolTipService.HasDropShadow="false"
ToolTipService.ShowOnDisabled="true"
ToolTipService.IsEnabled="true"

但是，我發現在TextBox的PreviewInput事件裏去彈出tooltip時， 以上的ToolTipService設置並沒有起到效果，Tooltip的彈出位置和顯示時間還是默認的， 即跟隨鼠標顯示，默認5s。

這個時候就需要對ToolTip的相關屬性進行設置。

            _toolTip.Style = ToolTipStyle;

            _toolTip.PlacementTarget = this.AssociatedObject;

            _toolTip.Placement = PlacementMode.Bottom;

當然，當我們toolTip和ToolTipService都設置相關屬性時， ToolTipService的設置優先。