Accomplish with Triggers the job of events from a TextBox in WPF

Hi i am trying to put what i am doing in the events from Code Behind in Triggers of a Style who is being applied in a TextBox. What i want is to prevent using the Code Behind to do that and use Triggers. Is there any way to accomplish this?

My Textbox

<TextBox Name="myTextBox"  Style="{StaticResource txtBoxStyle}"/>

My style

<Style x:Key="txtBoxStyle" TargetType="{x:Type TextBox}">
    <Setter Property="Foreground" Value="Silver"/>
    <Setter Prope开发者_Python百科rty="MaxLength" Value="6"/>
</Style>

The Events from Code Behind

private void myTextBox_LostFocus(object sender, RoutedEventArgs e)
{
    if (myTextBox.Text.Length == 0)
        myTextBox.Text = "000000";
}

private void myTextBox_GotFocus(object sender, RoutedEventArgs e)
{
    if (myTextBox.Text == "000000")
        myTextBox.Clear();
}

private void myTextBox_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (!(e.Key >= Key.D0 && e.Key <= Key.D9) && e.Key != Key.Back)
        e.Handled = true;
}

private void myTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
    if (myTextBox.Text == "000000")
        myTextBox.Foreground = Brushes.Silver;
    else
    {                
        myTextBox.Foreground = Brushes.Black;

        if(myTextBox.Text.Length == 6)
            myButton.Visibility = Visibility.Visible;
        else
            myButton.Visibility = Visibility.Hidden;
    }
}

Thanks in advance!

Edit: Using triggers for this logic is not a good idea and will in all likelihood fail because of its self-referencing (causes a stack-overflow), value converters are also a bit problematic. To encapsulate complex logic and apply it via a Style use an attached behavior.

<Style TargetType="{x:Type TextBox}">
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding IsFocused, RelativeSource={RelativeSource Self}}" Value="False"/>
                <Condition Binding="{Binding Text, RelativeSource={RelativeSource Self}}" Value=""/>
            </MultiDataTrigger.Conditions>
            <MultiDataTrigger.Setters>
                <Setter Property="Text" Value="000000"/>
            </MultiDataTrigger.Setters>
        </MultiDataTrigger>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding IsFocused, RelativeSource={RelativeSource Self}}" Value="True"/>
                <Condition Binding="{Binding Text, RelativeSource={RelativeSource Self}}" Value="000000"/>
            </MultiDataTrigger.Conditions>
            <MultiDataTrigger.Setters>
                <Setter Property="Text" Value=""/>
            </MultiDataTrigger.Setters>
        </MultiDataTrigger>
        <Trigger Property="Text" Value="000000">
            <Setter Property="Foreground" Value="Silver"/>
        </Trigger>
    </Style.Triggers>
    <!-- If (Text != "000000") Foreground = Brushes.Black -->
    <Setter Property="Foreground" Value="Black"/>
</Style>

The logic which sets the visibility of the button should not be handled in this style but by the button. The key-down event cannot be translated.

Button style:

<Style TargetType="{x:Type Button}">
    <Setter Property="Visibility" Value="Hidden"/> <!-- Normal state -->
    <Style.Triggers>
        <DataTrigger Binding="{Binding Text.Length, ElementName=myButton}" Value="6">
            <Setter Property="Visibility" Value="Visible"/>
        </DataTrigger>
    </Style.Triggers>
</Style>