访问数据模板中包含的控件

Question

I have a ContentControl which is used to display the current item in a CollectionViewSource.

This ContentControl used a DataTemplate to display a RichTextBox. I want to have access to the RichTextBox so I can scroll it to a predetermined location. However I can't seem to access it - how would I obtain a reference to the RichTextBox element?

Many thanks.

<CollectionViewSource x:Key="Results"
                      Source="{Binding Results}">
</CollectionViewSource>


<Grid.Resources>
    <!--Data Templates-->
    <DataTemplate DataType="{x:Type VFClass:Script}"
                  x:Key="scriptTemplate">
        <RichTextBox x:Name="ScriptViewRichTextBox"
                     local:RichTextBoxHelper.DocumentXaml="{Binding HighlightedRTF, IsAsync=False}"
                     BorderThickness="0"
                     ScrollViewer.CanContentScroll="True"
                     ScrollViewer.VerticalScrollBarVisibility="Auto"
                     IsReadOnly="{Binding ReadOnly}"
                     Margin="0"
                     ContextMenuOpening="RichTextBox_ContextMenuOpening"
                     Padding="5">
        </RichTextBox>
    </DataTemplate>
</Grid.Resources>



<ContentControl x:Name="ScriptText"
                Grid.Row="1"
                Margin="0"
                Content="{Binding IsAsync=False, Source={StaticResource Results}}"
                ContentTemplate="{StaticResource scriptTemplate}" />

Answer 1

Using VisualTreeHelper , you can drill down in the visual hierarchy. Assuming you have access to the ContentControl itself. (Recursively) use VisualTreeHelper.GetChildrenCount and VisualTreeHelper.GetChild to access the actual visual tree of the ContentControl , until you reach the RichTextBox you're interested in:

        int count = VisualTreeHelper.GetChildrenCount(contentControl);
        for (int i = 0; i < count; ++i)
        {
            DependencyObject d = VisualTreeHelper.GetChild(contentControl, i);
            if (d is RichTextBox)
            {
                //...do your thing
            }

            //  recurse (if necessary)...
        }

Answer 2

You can use FindName function of template like you have write in following code in you code behind

var template = ControlWhereTemplateAssign.Template;
var myControl = (RichTextBox)template.FindName("ScriptViewRichTextBox", ControlWhereTemplateAssign);

Answer 3

this would be much easier if a ControlTemplate is applied on the Control instead of a DataTemplate on the ContentPresenter

since the template is being assigned by name so it may not be an issue here.

start by modifying the template

<ControlTemplate x:Key="scriptTemplate">
    <RichTextBox x:Name="ScriptViewRichTextBox"
                 ... >
    </RichTextBox>
</ControlTemplate>

specify as

<ContentControl x:Name="ScriptText"
                ...
                Template="{StaticResource scriptTemplate}">

access the control as

    if (ScriptText.ApplyTemplate())
    {
        RichTextBox rtb = (RichTextBox)ScriptText.Template.FindName("ScriptViewRichTextBox", ScriptText);
    }

or (if template already applied)

    RichTextBox rtb = (RichTextBox)ScriptText.Template.FindName("ScriptViewRichTextBox", ScriptText);

however FindName applies to DataTemplate as well but there are few conditions which govern the template so you may encounter exceptions using this method

eg

This operation is valid only on elements that have this template applied.

using ControlTemplate you have option to apply template manually by calling ApplyTemplate() method, hence more safe to retrieve the template objects.