Can I apply a certain style for results from validation to only one button?

I'm working on a WPF-application in which I make validation with a mix of IDataErrorInfo and validation rules. For displaying the results of the validation at runtime I have made some styles in the XAML of the window. One of these styles should disable the save-button as long as there is an input error:

<Window.Resources>
    <!--Disabling the Save-button by style not viewmodel-property-->
    <Style TargetType="{x:Type Button}">
        <Style.Triggers>
            <DataTrigger Binding="{Binding ElementName=tbx_firstname, Path=(Validation.HasError)}" Value="true">
                <Setter Property="IsEnabled" Value="False"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding ElementName=tbx_lastname, Path=(Validation.HasError)}" Value="true">
                <Setter Property="IsEnabled" Value="False"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding ElementName=tbx_age, Path=(Validation.HasError)}" Value="true">
                <Setter Property="IsEnabled" Value="False"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Window.Resources>

I have two problems:

The style disables all buttons on the window. What can I do to only disable the save-button? I tried the following, but there seems to be a syntax-error (VS doesn't accept it):
```
<Style TargetType="{x:Name btn_save}">
```
In the style for the save-button I have to check each control that is validated. Is there another possibility to make that part shorter and less error-prone (because it has to combined with the viewmodel)?

Thanks in advance!

Solution

If you want your style to be applied to a single button instead of all of them, you need to assign a key to the style, e.g.:

<Style x:Key="SaveButtonStyle" TargetType="{x:Type Button}">

That way it will not be applied implicitly to all buttons. To apply it to your save button, explicitly specify the style on the button:

<Button Style="{StaticResource SaveButtonStyle}">