WPF - Find Control in ControlTemplate in WPF

In some scenario that requires we have to find a control within a ControlTemplate. To do that, you use Template.FindName method.

Let see how to find control from ControlTemplate.

Step 1
Create a WPF application and give a solution name as SolFindControlInControlTemplate.

Step 2
Add a button control on window,it is look like this

<Window x:Class="SolFindControlInControlTemplate.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Find Control in Control Template" Height="350" Width="525">
 <Grid>
        <Button Content="ChangeColor" Height="43" HorizontalAlignment="Left" Margin="155,126,0,0" Name="btnColor" VerticalAlignment="Top" Width="208"/>
    </Grid>
</Window>

Step 3
Create a simple ControlTemplate for button control,it is look like this

    <Window.Resources>

        <ControlTemplate x:Key="BtnControlTemplate" TargetType="Button">
            
            <Grid>
                
                <Rectangle x:Name="ButtonRecTangle" Stroke="Black" StrokeThickness="3" RadiusX="10" RadiusY="10" Fill="Orange">
                     
                </Rectangle>

                <!--For Display Text(Content) in button -->
                <Viewbox>
                    <!--set the button text which user will define on button-->
                    <ContentControl Content="{TemplateBinding Button.Content}"></ContentControl>

                </Viewbox>

            </Grid>
            
        </ControlTemplate>

    </Window.Resources>

Step 4

Apply ControlTemplate on button control,it is look like this

    <Grid>
        <Button Content="ChangeColor" Height="43" HorizontalAlignment="Left" Margin="155,126,0,0" Name="btnColor" VerticalAlignment="Top" Width="208" Template="{StaticResource BtnControlTemplate}" Click="btnColor_Click" />

    </Grid>

Step 5
Find a rectangle control in the ControlTemplate of btnColor and change the rectangle color,it is look like

  private void btnColor_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                // Find a rectangle control within a ControlTemplate by using Template.FindName method
                Rectangle RecTangleObj =(Rectangle) btnColor.Template.FindName("ButtonRecTangle", btnColor);

                // Fill the rectangle color
                RecTangleObj.Fill = System.Windows.Media.Brushes.Red;        
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);   
            }
        }

Full Code

1. XAML Code

<Window x:Class="SolFindControlInControlTemplate.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Find Control in Control Template" Height="350" Width="525">
    
    <Window.Resources>

        <ControlTemplate x:Key="BtnControlTemplate" TargetType="Button">
            
            <Grid>
                
                <Rectangle x:Name="ButtonRecTangle" Stroke="Black" StrokeThickness="3" RadiusX="10" RadiusY="10" Fill="Orange">
                     
                </Rectangle>

                <!--For Display Text(Content) in button -->
                <Viewbox>
                    <!--set the button text which user will define on button-->
                    <ContentControl Content="{TemplateBinding Button.Content}"></ContentControl>

                </Viewbox>

            </Grid>
            
        </ControlTemplate>

    </Window.Resources>  
    
    <Grid>
        <Button Content="ChangeColor" Height="43" HorizontalAlignment="Left" Margin="155,126,0,0" Name="btnColor" VerticalAlignment="Top" Width="208" Template="{StaticResource BtnControlTemplate}" Click="btnColor_Click" />
    </Grid>
</Window>

2. Code behind

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace SolFindControlInControlTemplate
{

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void btnColor_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                // Find a rectangle control within a ControlTemplate by using Template.FindName method
                Rectangle RecTangleObj =(Rectangle) btnColor.Template.FindName("ButtonRecTangle", btnColor);

                // Fill the rectangle color
                RecTangleObj.Fill = System.Windows.Media.Brushes.Red;        
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);   
            }
        }

       
    }
}

Run the project.

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