How to create a Dependency Property in a UserControl and how use it

You can refer the topic Read my post : How to create a dependency property in my blog.

Problem : we need to create a user control which having label and textbox in combine and we can change the label ,text and fore color of textbox where it is use.

Add a UserControl 

Put Label and textbox in XAML

<UserControl x:Class="CustomDP1.LabelTextBox"

             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

             mc:Ignorable="d" d:DesignWidth="300" Height="36.091">

    <Grid>

        <Grid.ColumnDefinitions>

            <ColumnDefinition Width="40*"/>

            <ColumnDefinition Width="60*"/>

        </Grid.ColumnDefinitions>

        <Label Content="Label" Name="lblDispaly" HorizontalAlignment="Stretch" Margin="0" VerticalAlignment="Stretch" Background="Gray"/>

        <TextBox Grid.Column="1" Name="txtDispaly" HorizontalAlignment="Stretch" Margin="0" VerticalAlignment="Stretch" TextWrapping="Wrap"  />

    </Grid>

</UserControl>

Create three Dependency property 

• TextBoxForeColorProperty 
• LabelTextProperty 
• TextBoxTextProperty 

    /// <summary>

    /// Interaction logic for LabelTextBox.xaml

    /// </summary>

    public partial class LabelTextBox : UserControl

    {

        public LabelTextBox()

        {

            InitializeComponent();

            this.Loaded += LabelTextBox_Loaded;

        }

        void LabelTextBox_Loaded(object sender, RoutedEventArgs e)

        {

            lblDispaly.Content = LabelText;

            txtDispaly.Text = TextBoxText;

            txtDispaly.Foreground = TextBoxForeColor;

        }

        public static readonly DependencyProperty TextBoxForeColorProperty = DependencyProperty.Register(

        "TextBoxForeColor",

        typeof(Brush),

        typeof(LabelTextBox),

        new PropertyMetadata(new SolidColorBrush(Colors.WhiteSmoke)));

        public Brush TextBoxForeColor

        {

            get { return (Brush)GetValue(TextBoxForeColorProperty); }

            set { SetValue(TextBoxForeColorProperty, value); }

        }

        public static readonly DependencyProperty LabelTextProperty = DependencyProperty.Register(

       "LabelText",

       typeof(string),

       typeof(LabelTextBox),

       new PropertyMetadata(null));

        public string LabelText

        {

            get { return (string)GetValue(LabelTextProperty); }

            set { SetValue(LabelTextProperty, value); }

        }

        public static readonly DependencyProperty TextBoxTextProperty = DependencyProperty.Register(

        "TextBoxText",

        typeof(string),

        typeof(LabelTextBox),

        new PropertyMetadata(null));

        public string TextBoxText

        {

            get { return (string)GetValue(TextBoxTextProperty); }

            set { SetValue(TextBoxTextProperty, value); }

        }

    }

Use this User control

Add the namespace of usercontrol
Add user control
now we can add values in custom dp(s)

<Window

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        xmlns:local="clr-namespace:CustomDP1" x:Class="CustomDP1.MainWindow"

        Title="Custom Control" Height="165.789" Width="501.316">

    <Grid>

        <local:LabelTextBox HorizontalAlignment="Left" VerticalAlignment="Top" Height="36" Width="356" LabelText="my label" TextBoxForeColor="Red"

                            TextBoxText="my custom textbox" Margin="59,45,0,0"/>

    </Grid>

</Window>

We can put these dp(s) values or bind with view model properties.