一个自定义FrameworkElement的例子

class：

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

namespace  WpfApplication25
{
     public   class  MyTextBlock : FrameworkElement
    {
        TextBlock t;
         public  MyTextBlock()
        {
            t  =   new  TextBlock() 
            {
                Text  =   " TextTextText " ,
                Background  =  Brushes.Blue,
                Width  =   60 ,
                Height  =   30
            };
            AddLogicalChild(t);
            AddVisualChild(t);
        }

         protected   override  Size MeasureOverride(Size availableSize)
        {
            t.Measure(availableSize);
             return   base .MeasureOverride(availableSize);
        }

         protected   override  Size ArrangeOverride(Size finalSize)
        {
            t.Arrange( new  Rect( new  Point( 50 ,  50 ), t.DesiredSize));
             return   base .ArrangeOverride(finalSize);
        }

         //  In order for the visual tree to be enumerated correctly,
         //  we must override the GetVisualChild and VisualChildrenCount.
         protected   override  Visual GetVisualChild( int  index)
        {
             return  t;
        }

         protected   override   int  VisualChildrenCount
        {
             get
            {
                 return   1 ;
            }
        }
    }
}
Xaml ：

< Window x:Class = " WpfApplication25.Window1 "
    xmlns = " http://schemas.microsoft.com/winfx/2006/xaml/presentation "
    xmlns:x = " http://schemas.microsoft.com/winfx/2006/xaml "
    Title = " Window1 "  Height = " 300 "  Width = " 300 "
        xmlns:local = " clr-namespace:WpfApplication25 " >
     < Grid >
         < local:MyTextBlock ></ local:MyTextBlock >
     </ Grid >
</ Window >