cannot set tooltip in style

Question

I searched and find out I can't set the tooltip in setter.value directly (in a style.xaml file). However I can use static resource to set the tooltip.

My question is, since I need to supply dynamic text for the tooltip, I can't use static resource. How should I do that?

here is my example.

    <Style x:Key="ErrorStyleRadius" TargetType="{x:Type FrameworkElement}">
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding (Validation.HasError), RelativeSource={RelativeSource Mode=Self}}" Value="True"/>
                <Condition Binding="{Binding (Validation.Errors), RelativeSource={RelativeSource Mode=Self}, Converter={StaticResource IsError}}" Value="True"/>
            </MultiDataTrigger.Conditions>
            <MultiDataTrigger.Setters>
                <Setter Property="ToolTip">
                    <Setter.Value>
                        <ToolTip>
                            <Label Content="{Binding somePropertyHere}"/>
                        </ToolTip>
                    </Setter.Value>
                </Setter>
                <Setter Property="Validation.ErrorTemplate" Value="{StaticResource ErrorControlTemplateRadiusError}"/>
            </MultiDataTrigger.Setters>
        </MultiDataTrigger>

        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding (Validation.HasError), RelativeSource={RelativeSource Mode=Self}}" Value="True"/>
                <Condition Binding="{Binding (Validation.Errors), RelativeSource={RelativeSource Mode=Self}, Converter={StaticResource IsWarning}}" Value="True"/>
            </MultiDataTrigger.Conditions>
            <MultiDataTrigger.Setters>
                <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors), Converter={StaticResource ValMsg}}"/>
                <Setter Property="Validation.ErrorTemplate" Value="{StaticResource ErrorControlTemplateRadiusWarning}"/>
            </MultiDataTrigger.Setters>
        </MultiDataTrigger>
    </Style.Triggers>
</Style>

for usage, i can use as

<textbox style={staticresource ErrorStyleRadius} text={bind name, validationOnDataError=true}/>

Answer 1

Why don't you try this -

<ToolTip x:Key="MyToolTip"
         DataContext={Binding PlacementTarget, RelativeSource={RelativeSource Self}}>
  <Label Content="{Binding Text}"/>
</ToolTip>

<Style x:Key="ErrorStyleRadius" TargetType="{x:Type FrameworkElement}">
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding (Validation.HasError), RelativeSource={RelativeSource Mode=Self}}" Value="True"/>
                <Condition Binding="{Binding (Validation.Errors), RelativeSource={RelativeSource Mode=Self}, Converter={StaticResource IsError}}" Value="True"/>
            </MultiDataTrigger.Conditions>
            <MultiDataTrigger.Setters>
                <Setter Property="ToolTip" Value={StaticResource MyToolTip}>
                </Setter>
                <Setter Property="Validation.ErrorTemplate" Value="{StaticResource ErrorControlTemplateRadiusError}"/>
            </MultiDataTrigger.Setters>
        </MultiDataTrigger>
    </Style.Triggers>
</Style>

You can give the property name in StaticResource. It will update the tooltip dynamically.

Answer 2

Also you can set the tooltip from your style if you want to set the text to Validation.Error like this -

<Trigger Property="Validation.HasError" Value="True">
       <Setter Property="ToolTip"
               Value="{Binding RelativeSource={RelativeSource Self},
                       Path=(Validation.Errors)[0].ErrorContent}" />
</Trigger>