MeasureOverride 和ArrangeOverride 浅理解

代码

   
     

    
      
    
       
    
      public
    
       
    
      class
    
       CustomControl1 : Panel
 {
 
    
      ///
    
       
    
      <summary>
    
      
 
    
      ///
    
       先测量需要多大尺寸，做个申报准备
 
    
      ///
    
       
    
      </summary>
    
      
 
    
      ///
    
       
    
      <param name="constraint">
    
      限定的尺寸，比如，规定了width和height
    
      </param>
    
      
 
    
      ///
    
       
    
      <returns></returns>
    
      

    
       
    
      protected
    
       
    
      override
    
       Size MeasureOverride(Size constraint)
 {
 
    
      //
    
      定义预期的宽度和高度
    
      

    
       
    
      double
    
       height 
    
      =
    
       
    
      0
    
      , width 
    
      =
    
       
    
      0
    
      ;
 UIElement element;
 
    
      //
    
      遍历每个元素，计算所需的总尺寸
    
      

    
       
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       Children.Count; i
    
      ++
    
      )
 {
 element 
    
      =
    
       Children[i];
 
    
      //
    
      按照限定的尺寸测量一下自己，拿镜子找着自己
    
      

    
       element.Measure(constraint);
 
    
      if
    
       (height 
    
      <
    
       element.DesiredSize.Height)
 height 
    
      =
    
       element.DesiredSize.Height;
 width 
    
      +=
    
       element.DesiredSize.Width;
 }
 
    
      //
    
      申报，我需要这个尺寸
    
      

    
       
    
      return
    
       
    
      new
    
       Size(width, height);
 }
 
 
    
      ///
    
       
    
      <summary>
    
      
 
    
      ///
    
       排列每个元素
 
    
      ///
    
       
    
      </summary>
    
      
 
    
      ///
    
       
    
      <param name="arrangeBounds">
    
      测量的尺寸
    
      </param>
    
      
 
    
      ///
    
       
    
      <returns></returns>
    
      

    
       
    
      protected
    
       
    
      override
    
       Size ArrangeOverride(Size arrangeBounds)
 {
 
    
      double
    
       currentX 
    
      =
    
       
    
      100
    
      ;
 UIElement element;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       Children.Count; i
    
      ++
    
      )
 {
 element 
    
      =
    
       Children[i];
 
    
      //
    
      排列每个元素
    
      

    
       Children[i].Arrange(
    
      new
    
       Rect(currentX, 
    
      0
    
      , element.DesiredSize.Width, element.DesiredSize.Height));
 currentX 
    
      +=
    
       element.DesiredSize.Width;
 }
 
    
      return
    
       arrangeBounds;
 }
 }
   
     

 

 

代码

   
     

    
      
    
       
    
      <
    
      local:CustomControl1 
    
      Width
    
      ="300"
    
       Background
    
      ="Gray"
    
       HorizontalAlignment
    
      ="Right"
    
       Margin
    
      ="0,20,151,280"
    
      >
    
      
 
    
      <
    
      Rectangle 
    
      Width
    
      ="100"
    
       Height
    
      ="50"
    
       Fill
    
      ="Red"
    
       Margin
    
      ="10,10,0,0"
    
       
    
      />
    
      
 
    
      <
    
      Rectangle 
    
      Width
    
      ="100"
    
       Height
    
      ="50"
    
       Fill
    
      ="Yellow"
    
       Margin
    
      ="10,10,0,0"
    
       
    
      />
    
      
 
    
      <
    
      Rectangle 
    
      Width
    
      ="100"
    
       Height
    
      ="50"
    
       Fill
    
      ="Green"
    
       Margin
    
      ="10,10,0,0"
    
       
    
      />
    
      
 
    
      </
    
      local:CustomControl1
    
      >