How to copy text with trigger

Question

Hi everyone,
I have two textboxes and I would copy the text from one to other when in third control Checkbox, property IsChecked becomes true.
I would get this operation using triggers avoiding event handling.
My question is if it possible to access in trigger to the properties of other controls.
The outline code is below:

<Window x:Class="Wizard.Window2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window2" Height="300" Width="300">
    <Grid>
        <Grid.Resources>
             <Style x:Key="CheckBoxStyle" TargetType="{x:Type CheckBox}">
            <Style.Triggers>
                <Trigger Property="IsChecked" Value="True">
                    <Setter ..... />
                </Trigger>
            </Style.Triggers>
        </Style>
        </Grid.Resources>
        
        <TextBox Height="23" Margin="42,28,116,0" Name="textBox1" VerticalAlignment="Top" Text="Text to Copy"/>
        <TextBox Height="23" Margin="42,75,116,0" Name="textBox2" VerticalAlignment="Top" />
        <CheckBox Height="18" Margin="0,0,0,112" Name="copyTextCheckBox" VerticalAlignment="Bottom" HorizontalAlignment="Left" Width="278"
                  Style="{StaticResource CheckBoxStyle}">
            <TextBlock TextWrapping="Wrap"  Height="28" Margin="0,0,0,0"
                       Name="checkBox1" Text="Copy Text from TextBox1 to TextBox2 with Trigger"/>
        </CheckBox>
    </Grid>
</Window><br/><br/><br/>
<br/><br/><br/><br/><br/><br/>

T


Thanks in advance,
Mauro

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Mauro

Answer 1

Hi Mauro,

> My question is if it possible to access in trigger to the properties of other controls.

Yes, but not in the way you mentioned, i.e. set a property of other control from the style of a control. The correct way is to use data binding. See the following sample for detailed information on how to do this.

<TextBox Height="23" Margin="42,75,116,0" Name="textBox2" VerticalAlignment="Top">
         <TextBox.Style>
                <Style TargetType="TextBox">
                    <Style.Triggers>                
                        <DataTrigger Binding="{Binding ElementName=copyTextCheckBox,Path=IsChecked}" Value="True">
                            <Setter Property="Text" Value="{Binding ElementName=textBox1,Path=Text}"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
           </TextBox.Style>
 </TextBox>

Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu

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Answer 2

Hi Linda,
thanks for your useful reply.
My goal was handling all the code in xaml.
Your code solve my problem overulling my point of view: when in CheckBox IsChecked=True is the TextBox.Style of the control that receives the Data that handles the new value with DataTrigger.  
So no Event Trigger but Data Trigger.
Many thanks,
Mauro

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Mauro