WPF how to set a tooltip to textbox (in style file)

I wanted to have nice ToolTip for my TextBox, so I started with simple ToolTip:

   <TextBox>
       <TextBox.ToolTip>
           <StackPanel>
               <TextBlock>Nice text</TextBlock>
               <TextBlock>Nice text</TextBlock>
           </StackPanel>
       </TextBox.ToolTip>
   </TextBox>

However I have a dozen TextBoxes and I wanted them all to have the ToolTip above. That's why I decided to transfer the code above into a Style file.

My Style file looks like:

   <Style x:Key="DefaultStyle" TargetType="{x:Type TextBox}">
    <Setter Property="FontFamily" Value="Tahoma"/>
    <Setter Property="FontSize" Value="15"/>
    <Setter Property="VerticalContentAlignment" Valu开发者_开发问答e="Center"/>
    <Setter Property="TextAlignment" Value="Center"/>
    <Setter Property="TextWrapping" Value="Wrap"/>
    <Setter Property="BorderBrush" Value="#A9C2DE"/>
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="Background">
        <Setter.Value>
            <LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1" >
                <GradientStop Color="#CDE1F7" Offset="0.01"/>
                <GradientStop Color="#DFECFA" Offset="0.8" />
            </LinearGradientBrush>
        </Setter.Value>
    </Setter>
    <Setter Property="ToolTip">
        <Setter.Value>
            <StackPanel>
                <TextBlock Text="Nice toolbox"/>
                <TextBlock Text="Nice tooltip"/>
            </StackPanel>
        </Setter.Value>
    </Setter>
</Style>

However now I get error XAML parse exception.

How can I set this kind of ToolTip (with StackPanels etc) to TextBox (from style file)??

Dotnet Version < 4

The style looks good but there seems to be an issue with specifing the tooltip directly in the styles value. Declare the ToolTip as a resource and then set it in the style via StaticResource.

<ToolTip x:Key="YourToolTip" >        
    <StackPanel>
        <TextBlock Text="Nice toolbox"/>
        <TextBlock Text="Nice tooltip"/>
    </StackPanel>
</ToolTip>

... Your Style...
<Setter Property="TextBox.ToolTip" Value="{StaticResource YourToolTip}"/>
...

Dotnet Version == 4

If you work with .net4, it's something other. You wrote that you put it into a style file. Do you mean a resource-file? If yes, may be you have not loaded it during runtime. Something like:

<Window.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="/YourStyleFile.xaml"/>
            <ResourceDictionary>
                 <!-- Other local resources -->
            </ResourceDictionary>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Window.Resources>

Another possibility is that you try to use it on another type than TextBox. This does not work because you declared TextBox as target type.