A Dependency property is a property which allow the analytical code to modify the properties of an object to minimize a data necessities by giving a powerful reporting system about to change of a data in a particular way.

In dot net generally we have a two types of properties:
1. Normal property
2. DependencyProperty

 In this blog we discuss the Dependency property.
To implement the Dependency Property we need to implement a UserControl class from a INotifyPropertyChanged interface first.

public partial class UserControlDependencyProperty  : UserControl, INotifyPropertyChanged 
{ 
    public event PropertyChangedEventHandler PropChange; 
    protected void OnPropertyChanged(string propName) 
    { 
        if (PropChange!= null) 
        { 
            PropChange(this, new PropertyChangedEventArgs(propName)); 
        } 
    } 
}

Now create a normal property with name "Triangle"

public string Triangle
{  
    get { return GetValue(TriangleProperty).ToString(); }  
    set { SetValue(TriangleProperty, value); } 
}

After creating normal property we need to pass a property field that is used to store the data in above code as a parameter to a Register method to register the DependencyProperty in the CLR.

public static readonly DependencyProperty TriangleProperty =
  DependencyProperty.Register("Triangle", typeof(string), typeof(UserControlDependencyProperty),
  new PropertyMetadata(string.Empty, OnTrianglePropertyChanged));

Code for OnTrianglePropertyChanged event handler:

private static void OnTrianglePropertyChanged(DependencyObject dependObject, 
               DependencyPropertyChangedEventArgs e) 
{  
    UserControlDependencyProperty userControl = dependObject as UserControlDependencyProperty ;  
    UserControlDependencyProperty.OnPropertyChanged("Triangle");  
    UserControlDependencyProperty.OnTrianglePropertyChanged(e); 
}
private void OnTrianglePropertyChanged(DependencyPropertyChangedEventArgs e) 
{ 
    txt1.Text = Triangle; 
}

Code for XAML

<local:UserControlDependencyProperty triangle=" This is the Dependency Property Example" />