Change TextBlock inside TextBox Template with Binding-CodePudding

I created a custom control which is a TextBox that contains a TexBlock inside. This TexBlock dissapear if the place holder text(Directorio Archivo) is empty. It works and it was perfect for my initianl needs, but now I need to reuse that custom control with other place holder text. I am new on WPF and its a little overwhelming for me right now. The following code shows a working template for one specific situation:

        <Style x:Key="DefaultTextBox" TargetType="TextBox">
            <Setter Property="IsReadOnly" Value="True"/>
            <Setter Property="Margin" Value="10, 5"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="TextBox">
                        <Border Background="#ffffff" BorderBrush="#000000" BorderThickness="1" CornerRadius="5" >
                            <Grid>
                                <TextBox x:Name="Directorio" Background="Transparent" BorderThickness="0" Margin="5" VerticalContentAlignment="Center" Text="{TemplateBinding Text}"/>
                                <TextBlock Foreground="#828282" HorizontalAlignment="Center" IsHitTestVisible="False" Margin="5" Text="Directorio Archivo">
                                    <TextBlock.Style>
                                        <Style TargetType="{x:Type TextBlock}">
                                            <Style.Triggers>
                                                <DataTrigger Binding="{Binding Text, ElementName=Directorio}" Value="">
                                                    <Setter Property="Visibility" Value="Visible"/>
                                                </DataTrigger>
                                            </Style.Triggers>
                                            <Setter Property="Visibility" Value="Hidden"/>
                                        </Style>
                                    </TextBlock.Style>
                                </TextBlock>
                            </Grid>
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

Now I want to re use the template and replace the text "Directorio Archivo" for something defined on the control. This portion of code I want to change:

<TextBlock Foreground="#828282" HorizontalAlignment="Center" IsHitTestVisible="False" Margin="5" Text="{Templatebinding or binding?????}">

Now if I could just replace the text of that place holder field calling it like this for example:

<TextBox Grid.Row="0" Grid.Column="1" Margin="5,5,20,5" Style="{StaticResource DefaultTextBox}" TextBlock.Text="MyPlaceHolderText"/>

I have tried everything but I am struggling to understand how WPF works and its documentation is not very easy to follow.

Thanks In advance

CodePudding user response：

You either need to define a custom dependency property to store the value of the text, or you could use an existing property such as Tag:

<TextBox ... Tag="Directorio Archivo" />

You then modify the template to bind to this property:

<TextBlock Foreground="#828282" ... Text="{TemplateBinding Tag}">