IEllipticArc.PutCoords使用疑问

开发环境：C#2005 + AE9.2<br><br><br>在使用IEllipticArc.PutCoords时总是报错：“这个集合中找不到项目”。AE自带的.NET help fro VS2005中Example程序如下：<br><br><br>// Get the Application Handle and the display<br><br>//Use IEllipticArc.PutCoords to Input the Center, Start and End points to create an EllipticArc.  <br><br><br>IPoint startPoint = new PointClass(); <br><br>startPoint.PutCoords(100, 100);<br><br><br>IPoint centerPoint = new PointClass(); <br><br>centerPoint.PutCoords(250, 100); <br><br><br>IPoint endPoint = new PointClass(); <br><br>endPoint.PutCoords(400, 100);<br><br><br>IEllipticArc ellipticArc = new EllipticArcClass();  <br><br>//Draw a Elliptic arc with Solid line symbol. <br><br>ellipticArc.PutCoords(false, centerPoint, startPoint, endPoint, Math.PI, 1 / 3, esriArcOrientation.esriArcClockwise);<br><br><br>这段程序确实运行无误，但是，当我把startPoint、centerPoint和endPoint的Y坐标分别改成100、200和300后，则仍会报出“这个集合中找不到项目”错误，如图所示：<br>
<DIV>
<DIV class="right smalltxt"> <IMG src="http://bbs.esrichina-bj.cn/ESRI/attachments/forumid_26/20070919_a5ea134bf59559950d65HHPBZ8vDt312.jpg" border=0></DIV></DIV><br><br>难不成Y坐标必须相等？我不相信有此荒谬之事，于是在ArcMap中用VBA进行调试，代码如下：<br><br><br>     Dim pCPt As IPoint, pSPt As IPoint, pEPt As IPoint<br><br>     <br><br>     Set pSPt = eCreatePoint(100, 100)<br><br>     Set pEPt = eCreatePoint(400, 300)<br><br>     Set pCPt = eCreatePoint(250, 200)<br><br>     <br><br>     Dim pEllipticArc As IEllipticArc<br><br>     Set pEllipticArc = New EllipticArc<br><br>     <br><br>     pEllipticArc.PutCoords False, pCPt, pSPt, pEPt, 3.14, 1 / 3, esriArcClockwise<br><br><br>结果运行正确，如图所示：<br>
<DIV>
<DIV class="right smalltxt"> </DIV></DIV><IMG src="http://bbs.esrichina-bj.cn/ESRI/attachments/forumid_26/20070919_c71876986b78eedc3e17JL5MIUN2lcS1.jpg" border=0><br><br><br>那么，请教一下，我在C#中遇到的错误是怎么回事呢？谢谢大家！