如何用MapControl.DrawShape画圆弧

这样可以画出polylon
mapcontrol.drawshape(ippolyline2<I></I> as<I></I> igeometry,<I></I> ref<I></I> objlinestyle);
但用同样的方法画圆弧的时候就显示不出来。。。。。
还清高手指教……<img src="images/post/smile/dvbbs/em08.gif" /><img src="images/post/smile/dvbbs/em08.gif" /><img src="images/post/smile/dvbbs/em08.gif" />

<P>在arcmap的编辑工具扩展里</P><P>COGO模块里可以画曲线，设置曲线的各种参数</P>

<PRE>下面的程序应该能满足楼猪要求</PRE><PRE> </PRE><PRE> </PRE>

<P>Option Explicit
Sub Test()
    Dim pMxDoc As IMxDocument
    Set pMxDoc = ThisDocument
    
    Dim pEnv As IEnvelope
    Set pEnv = pMxDoc.ActiveView.Extent
    pEnv.Expand 0.5, 0.5, True
    
    Dim pPoint As IPoint
    Set pPoint = New Point
    pPoint.PutCoords (pEnv.LowerLeft.x + pEnv.LowerRight.x) / 2#, pEnv.LowerLeft.y
    
    Dim pPolygon As IPolygon
    Set pPolygon = MakeClosedArc(pEnv.LowerLeft, pPoint, pEnv.LowerRight)
    
    With pMxDoc.ActiveView.ScreenDisplay
        .StartDrawing .hDC, esriNoScreenCache
        .SetSymbol New SimpleFillSymbol
        .DrawPolygon pPolygon
        .FinishDrawing
    End With
End Sub</P><P>Private Function MakeClosedArc(pFromPoint As IPoint, _
                               pCenterPoint As IPoint, _
                               pToPoint As IPoint) As IPolygon
    Dim pCArc As ICircularArc
    Set pCArc = New CircularArc
    pCArc.PutCoords pCenterPoint, pFromPoint, pToPoint, esriArcClockwise
  
    Dim pSegColl As ISegmentCollection
    Set pSegColl = New Ring
    pSegColl.AddSegment pCArc
    
    Dim pRing As IRing
    Set pRing = pSegColl
    pRing.Close
    
    Dim pGeomColl As IGeometryCollection
    Set pGeomColl = New Polygon
    pGeomColl.AddGeometry pRing
    Set MakeClosedArc = pGeomColl
    
End Function</P>

<P>谢谢楼上！</P><P>我将vb的代码转成c#，编译后有些问题不知道怎么解决。。。。</P><P>希望帮帮忙！！！！！    </P><P>ICircularArc ipCircularArc = new CircularArcClass();
    ipCircularArc.PutCoords(ipCenterPoint, ipFormPoint, ipToPoint, esriArcOrientation.esriArcClockwise);</P><P>
    ISegmentCollection ipSegmentCollection = new RingClass();
    ipSegmentCollection.AddSegment(ipCircularArc as ISegment, before,after);  </P><P>//before,after这两个参数怎么设置？
    IRing ipRing = ipSegmentCollection as IRing;
    ipRing.Close();
    IGeometryCollection ipGeometryCollection = new PolygonClass();
    IGeometry[] ipGeom = new RingClass[2];
    ipGeom[0] = new RingClass();
    ipGeom[0] = ipRing;</P><P>    ipGeometryCollection.AddGeometries(count, ipGeom);  
    ipPolygon = ipGeometryCollection as IPolygon;
</P><img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em02.gif" />

这个你就可以看看AddSegment在帮助里的说明了

<P>object pobject = Type.Messing;</P><P>ipSegmentCollection.AddSegment(ipCircularArc as ISegment, ref pobject,ref pobject);  </P>

学习，。。。。<img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em02.gif" />