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20.2.2 Size和SizeF结构
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20.2.2 Size和SizeF结构
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<h1 id="divCurrentNode" style="color: #b83507; width: 100%; text-align: left; font-size: 12px; padding-left: 2px">当前章节:<a href='100165566.htm'><font color='red'>20.2.2 Size和SizeF结构</font></a></h1>
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<div style='float:left;width:49%'>·<a href='100165563.htm'>20.1.4 使用剪切区域</a></div><div style='float:right;width:49%'>·<a href='100165564.htm'>20.2 测量坐标和区域</a></div><div style='float:left;width:49%'>·<a href='100165565.htm'>20.2.1 Point和PointF结构</a></div><div style='float:right;width:49%'>·<a href='100165567.htm'>20.2.3 Rectangle和RectangleF结构</a></div><div style='float:left;width:49%'>·<a href='100165568.htm'>20.2.4 Region</a></div><div style='float:right;width:49%'>·<a href='100165569.htm'>20.3 调试须知</a></div></div>
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<div id="text"> <link href="css.css" rel="stylesheet" type="text/css" /><h3 style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 0cm; MARGIN-RIGHT: 0cm; FTEL: 8.15pt"><a ftel="_Toc507815359"><span lang="EN-US">20.2.2 Size</span></a><span style="FONT-FAMILY: 黑体">和</span><span lang="EN-US">SizeF</span><span style="FONT-FAMILY: 黑体">结构</span></h3>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">与</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">PointF</span><span style="FONT-FAMILY: 宋体">一样，</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">也有两个变体。</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">结构用于</span><span lang="EN-US">int</span><span style="FONT-FAMILY: 宋体">类型，</span><span lang="EN-US">SizeF</span><span style="FONT-FAMILY: 宋体">用于</span><span lang="EN-US">float</span><span style="FONT-FAMILY: 宋体">类型，除此之外，</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> SizeF</span><span style="FONT-FAMILY: 宋体">是完全相同的。下面主要讨论</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">结构。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">在许多情况下，</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">结构与</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">结构是相同的，它也有两个整型属性，表示水平和垂直距离</span><span lang="EN-US" style="LETTER-SPACING: -1pt">—— </span><span style="FONT-FAMILY: 宋体">主要区别是这两个属性的名称不是</span><span lang="EN-US">X</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">Y</span><span style="FONT-FAMILY: 宋体">，而是</span><span lang="EN-US">Width </span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> Height</span><span style="FONT-FAMILY: 宋体">。前面的图</span><span lang="EN-US">20-3</span><span style="FONT-FAMILY: 宋体">可以表示为：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">Size ab = new Size(20,10);</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">Console.WriteLine("Moved {0} across, {1} down", ab.Width, ab.Height);</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">严格地讲，</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">在数学上与</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">表示的含义相同；但在概念上它使用的方式略有不同。</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">用于说明实体在什么地方，而</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">用于说明实体有多大。但是，</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">是紧密相关的，目前甚至支持它们之间的显式转换：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> Point point = new Point(20, 10);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Size size = (Size) point;</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> Point anotherPoint = (Point) size;</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">例如，考虑前面绘制的矩形，其左上角的坐标是</span><span lang="EN-US">(0,0)</span><span style="FONT-FAMILY: 宋体">，大小是</span><span lang="EN-US">(50,50)</span><span style="FONT-FAMILY: 宋体">。这个矩形的大小是</span><span lang="EN-US">(50,50)</span><span style="FONT-FAMILY: 宋体">，可以用一个</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">实例来表示。其右下角的坐标也是</span><span lang="EN-US">(50,50)</span><span style="FONT-FAMILY: 宋体">，但它由一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">实例来表示。要理解这个区别，假定在另一个位置绘制该矩形，其左上角的坐标是</span><span lang="EN-US">(10,10)</span><span style="FONT-FAMILY: 宋体">：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">dc.DrawRectangle(bluePen, 10,10,50,50);</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">现在其右下角的坐标是</span><span lang="EN-US">(60,60)</span><span style="FONT-FAMILY: 宋体">，但大小不变，仍是</span><span lang="EN-US">(50,50)</span><span style="FONT-FAMILY: 宋体">。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">结构的相加运算符都已经重载了，所以可以把一个</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">加到</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">结构上，得到另一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">结构：</span></p>
<p class="a6" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">static void Main(string[] args)</span></p>
<p class="a6" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">{</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><a ftel="OLE_LINK10"><span lang="EN-US"> Point topLeft = new Point(10,10);</span></a></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Size rectangleSize = new Size(50,50);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Point bottomRight = topLeft + rectangleSize;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Console.WriteLine("topLeft = " + topLeft);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Console.WriteLine("bottomRight = " + bottomRight);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Console.WriteLine("Size = " + rectangleSize);</span></p>
<p class="a6" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">}</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">把这段代码作为控制台应用程序</span><span lang="EN-US">PointAndSizes</span><span style="FONT-FAMILY: 宋体">来运行，会得到如图</span><span lang="EN-US">20-4</span><span style="FONT-FAMILY: 宋体">所示的结果。</span></p>
<p align="center"><span lang="EN-US"><img height="109" src="20/image004.jpg" width="357" alt="" /></span></p>
<p style="FTEL: 8.15pt" align="center"><span style="FONT-FAMILY: 宋体">图</span><span lang="EN-US"> 20-4</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">注意这个结果也说明了</span><span lang="EN-US">Point </span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> Size</span><span style="FONT-FAMILY: 宋体">的</span><span lang="EN-US">ToString()</span><span style="FONT-FAMILY: 宋体">方法已被重写并以</span><span lang="EN-US">{X,Y}</span><span style="FONT-FAMILY: 宋体">格式显示值。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">也可以从一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">减去某个</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">，得到另一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">，还可以把两个</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">加在一起，得到另一个</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">。但不能把一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">加到另一个</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">上。</span><span lang="EN-US">Microsoft</span><span style="FONT-FAMILY: 宋体">认为</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">相加在概念上没有意义，所以不支持＋运算符的任何重载进行这样的操作。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 17.6pt"><span style="FONT-FAMILY: 宋体">还可以在</span><span lang="EN-US">Point</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">Size</span><span style="FONT-FAMILY: 宋体">之间进行显式的数据类型转换：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">Point topLeft = new Point(10,10);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">Size s1 = (Size)topLeft;</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">Point p1 = (Point)s1;</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">在进行这样的数据类型转换时，</span><span lang="EN-US">s1.Width</span><span style="FONT-FAMILY: 宋体">被赋予</span><span lang="EN-US">topLeft.X</span><span style="FONT-FAMILY: 宋体">的值，</span><span lang="EN-US">s1.Height</span><span style="FONT-FAMILY: 宋体">被赋予</span><span lang="EN-US">topLeft.Y</span><span style="FONT-FAMILY: 宋体">的值，因此</span><span lang="EN-US">s1</span><span style="FONT-FAMILY: 宋体">包含</span><span lang="EN-US">(10,10)</span><span style="FONT-FAMILY: 宋体">。</span><span lang="EN-US">p1</span><span style="FONT-FAMILY: 宋体">最终的值与</span><span lang="EN-US">topLeft</span><span style="FONT-FAMILY: 宋体">的值相同。</span></p></div>
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<div style='float:left;width:49%'>·<a href='100165563.htm'>20.1.4 使用剪切区域</a></div><div style='float:right;width:49%'>·<a href='100165564.htm'>20.2 测量坐标和区域</a></div><div style='float:left;width:49%'>·<a href='100165565.htm'>20.2.1 Point和PointF结构</a></div><div style='float:right;width:49%'>·<a href='100165567.htm'>20.2.3 Rectangle和RectangleF结构</a></div><div style='float:left;width:49%'>·<a href='100165568.htm'>20.2.4 Region</a></div><div style='float:right;width:49%'>·<a href='100165569.htm'>20.3 调试须知</a></div></div>
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