[WPF] 카카오톡 구현 6 - ComboBox BackGround 변경하기

✍ ComboBox의 BackGround 속성을 변경해도 변경되지 않는 걸 볼 수 있다. 

✔ 그래서 비하인드 코드에서 설정을 해줘야 한다. 

namespace WpfAttachedProperty
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            Loaded += MainWindow_Loaded;

        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            cmb.SetBackground(Brushes.Red);
        }
    }
}

 

💻 ComboBoxBackgroundExtension

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;

namespace WpfAttachedProperty
{
    public static class ComboBoxBackgroundExtension
    {
        public static void SetBackground(this ComboBox combo, Brush brush)
        {
            var toggleButton = (ToggleButton)combo.Template.FindName("toggleButton", combo);
            if (toggleButton != null)
            {
                var border = (Border)toggleButton.Template.FindName("templateRoot", toggleButton);
                if (border != null)
                {
                    border.Background = brush;
                }
            }

            var textBox = (TextBox)combo.Template.FindName("PART_EditableTextBox", combo);
            if (textBox != null)
            {
                var parent = (Border)textBox.Parent;
                parent.Background = brush;
            }
        }
    }
}

 

 

그러나 이 방법은 MVVM 패턴에 위반 되므로 다른 방법으로 다시 할 예정 

 

 

💻 ComboBoxBackgroundExtension

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;

namespace WpfAttachedProperty
{
    public static class ComboBoxBackgroundExtension
    {
        public static void SetBackground(this ComboBox combo, Brush brush)
        {
            var toggleButton = (ToggleButton)combo.Template.FindName("toggleButton", combo);
            if (toggleButton != null)
            {
                var border = (Border)toggleButton.Template.FindName("templateRoot", toggleButton);
                if (border != null)
                {
                    border.Background = brush;
                }
            }

            var textBox = (TextBox)combo.Template.FindName("PART_EditableTextBox", combo);
            if (textBox != null)
            {
                var parent = (Border)textBox.Parent;
                parent.Background = brush;
            }
        }
    }
}

💻 ComboBoxBackgroundManager

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace WpfAttachedProperty
{
    public class ComboBoxBackgroundManager
    {
        private static Brush? _newBrush = null;

        public static Brush GetBackground(DependencyObject obj)
        {
            return (Brush)obj.GetValue(BackgroundProperty);
        }

        public static void SetBackground(DependencyObject obj, Brush value)
        {
            obj.SetValue(BackgroundProperty, value);
        }

        public static readonly DependencyProperty BackgroundProperty =
            DependencyProperty.RegisterAttached("Background", typeof(Brush), typeof(ComboBoxBackgroundManager), new UIPropertyMetadata(Brushes.Transparent, BackgroundChanged));


        private static void BackgroundChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var cmb = d as ComboBox;
            if(cmb == null) return;

            if(e.NewValue != e.OldValue)
            {
                _newBrush = (Brush)e.NewValue;
                cmb.Loaded -= Cmb_Loaded;
                cmb.Loaded += Cmb_Loaded;
                cmb.Unloaded -= Cmb_Unloaded;
                cmb.Unloaded += Cmb_Unloaded;
            }
        }

        private static void Cmb_Unloaded(object sender, RoutedEventArgs e)
        {
            var cmb = (ComboBox)sender;
            cmb.Loaded -= Cmb_Loaded;
            cmb.Unloaded -= Cmb_Unloaded;
            _newBrush = null;
        }

        private static void Cmb_Loaded(object sender, RoutedEventArgs e)
        {
            var cmb = (ComboBox)sender;
            cmb.SetBackground(_newBrush ?? Brushes.Transparent);
        }
    }
}

💻 MainWindow.xaml / cs

<Window x:Class="WpfAttachedProperty.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfAttachedProperty"
        mc:Ignorable="d"
        Title="MainWindow" Height="323" Width="403">
    <StackPanel>
        <TextBlock Text="ComboBox"/>
        <ComboBox x:Name="cmb" 
                  IsEditable="True" 
                  Margin="5 0"
                  local:ComboBoxBackgroundManager.Background="Blue"/>
    </StackPanel>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
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 WpfAttachedProperty
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            Loaded += MainWindow_Loaded;

        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {

        }
    }
}

 

💻

<Window x:Class="WpfAttachedProperty.MainView2"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfAttachedProperty"
        mc:Ignorable="d"
        Title="MainView2" Height="450" Width="800">
    <Grid>
        <ComboBox Grid.Row="0" local:ComboBoxBackgroundManager.Background="Yellow"/>
    </Grid>
</Window>

--> 이렇게 새로운 파일은 만들어서 배경색을 변경해도 잘 적용되는 걸 볼 수 있다. 

범용적으로 AttachedProperty를 사용할 수 있다.