摘要：
ToolTip或PopUp控件通常用于界面中。如何自定义工具提示？
1.首先自定义tooltip的controlTemplate，完全清除系统默认效果， 如下：
<ControlTemplatex:Key="TooltipTemplate"TargetType="ToolTip">
<ContentPresenterx:Name="contentPresenter"Height="{TemplateBindingHeight}"Width="{TemplateBindingWidth}"ContentTemplate="{TemplateBindingContentTemplate}" ></ContentPresenter>
</ControlTemplate>
2.自定义tooltip的contentTemplate， 这样可以专注于tooltip的界面呈现， 而不关心tooltip要显示的字符串， 如下：
<Stylex:Key="ToolTipStyle"TargetType="ToolTip">
<SetterProperty="IsOpen"Value="False">
</Setter>
<SetterProperty="ContentTemplate">
<Setter.Value>
<DataTemplate>
<Borderx:Name="errorBorder"Background="#CC595959"BorderBrush="#99000000"BorderThickness="1"CornerRadius="3"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"Margin="0"MaxWidth="320">
<Border.Effect>
<DropShadowEffectBlurRadius="4"ShadowDepth="0"/>
</Border.Effect>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinitionWidth="Auto"/>
<ColumnDefinitionWidth="*"/>
</Grid.ColumnDefinitions>
<BorderMargin="16,16,8,16"VerticalAlignment="Top">
<Pathx: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>
<TextBlockx:Name="textBlock"Text="{TemplateBindingContent}"Margin="0,14,10,14"FontSize="14"Grid.Column="1"TextWrapping="Wrap"Foreground="Red"/>
</Grid>
</Border>
</DataTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<TriggerProperty="IsOpen"Value="True">
<Trigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<ObjectAnimationUsingKeyFramesStoryboard.TargetProperty="Visibility"Duration="0:0:3">
<DiscreteObjectKeyFrameKeyTime="0:0:0">
<DiscreteObjectKeyFrame.Value>
<Visibility>Visible</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
<DiscreteObjectKeyFrameKeyTime="0:0:3">
<DiscreteObjectKeyFrame.Value>
<Visibility>Hidden</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
</Trigger>
</Style.Triggers>
</Style>
3.应用Tooltip的style，如下：
<ButtonContent="TestButton">
<Button.ToolTip>
<ToolTipStyle="{DynamicResourceToolTipStyle}" Content="This is a button"></ToolTip>
</Button.ToolTip>
</Button>
4.以上style使用时的注意事项：
因为Animation的设置值优先于本地设置值，所以会出现ToolTip在动画结束时永远隐藏。
因此在需要打开tooltip时，首先要在动画开始时设置Visibility为Visible，第二要触发IsOpen=True则必须先IsOpen=False， 因为在Tooltip隐藏后并没有设置IsOpen=False。
代码如下：
_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
对于ToolTip的显示延迟、显示时间长度、是否保持显示、显示时的位置等等，通用的做法都是通过ToolTipService来进行统一设置。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，我发现在TextBox的PreviewInput事件里去弹出tooltip时， 以上的ToolTipService设置并没有起到效果，Tooltip的弹出位置和显示时间还是默认的， 即跟随鼠标显示，默认5s。
这个时候就需要对ToolTip的相关属性进行设置。
_toolTip.Style = ToolTipStyle;
_toolTip.PlacementTarget = this.AssociatedObject;
_toolTip.Placement = PlacementMode.Bottom;
当然，当我们toolTip和ToolTipService都设置相关属性时， ToolTipService的设置优先。