IElement pEle = pLineEle as IElement;
pEle.Geometry = pLn;
pLn为一个ILine对象，想当然的以为它是IGeometry对象，可以赋值，结果爆出异常值不在预期范围内。
解决方法是将ILine转换为IPolyline对象，涉及到一些Geometry的基本操作。贴出一些可用的绘制元素的代码
#region 获取RgbColor
/// <summary>
/// 获取RgbColor颜色对象
/// </summary>
/// <param name="r"></param>
/// <param name="g"></param>
/// <param name="b"></param>
/// <param name="alpa">可选参数,透明度.0代表透明</param>
/// <returns></returns>
public static IRgbColor getRgbColor(int r, int g, int b, byte alpa = 255)
{
IRgbColor pColor = new RgbColorClass();
pColor.Red = r;
pColor.Green = g;
pColor.Blue = b;
pColor.Transparency = alpa; return pColor;
}
#endregion #region 获取随机颜色
/// <summary>
/// 获取随机颜色
/// </summary>
/// <returns></returns>
public static IRgbColor getRandColor()
{
Random rd = new Random();
IRgbColor myColor = new RgbColorClass();
myColor.Red = rd.Next(0, 255);
myColor.Blue = rd.Next(0, 255);
myColor.Green = rd.Next(0, 255); return myColor;
}
#endregion #region 绘制线
/// <summary>
/// 绘制线
/// </summary>
/// <param name="pLine"></param>
/// <param name="pMapCtrl"></param>
/// <param name="pLineSymbol">线符号</param>
/// <param name="refresh">刷新</param>
public static void DrawLine(ILine pLine, IMapControl2 pMapCtrl, ISimpleLineSymbol pLineSymbol
, bool refresh)
{
ILineElement pLineEle = new LineElementClass();
pLineEle.Symbol = pLineSymbol;
IGeometryCollection pPolyline = new PolylineClass();
ISegmentCollection pPath = new PathClass();
object m1 = Type.Missing;
object m2 = Type.Missing;
pPath.AddSegment(pLine as ISegment, ref m1, ref m2);
pPolyline.AddGeometry(pPath as IGeometry, ref m1, ref m2);
IElement pEle = pLineEle as IElement;
pEle.Geometry = pPolyline as IGeometry;
IGraphicsContainer pGC = pMapCtrl.Map as IGraphicsContainer;
pGC.AddElement(pEle, 0);
if (refresh)
{
IActiveView pAv = pMapCtrl.ActiveView;
pAv.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
}
#endregion #region 绘制文字注记
/// <summary>
/// 绘制文字
/// </summary>
/// <param name="pnt"></param>
/// <param name="value"></param>
/// <param name="ptxtSym"></param>
/// <param name="pMapCtrl"></param>
/// <param name="refresh"></param>
public static void DrawTextEle(IPoint pnt, string strvalue, ITextSymbol ptxtSym,
IMapControl2 pMapCtrl, bool refresh)
{
ITextElement pTextEle = new TextElementClass();
pTextEle.Text = strvalue;
pTextEle.Symbol = ptxtSym; IElement pEle = pTextEle as IElement;
pEle.Geometry = pnt;
IGraphicsContainer pGc = pMapCtrl.Map as IGraphicsContainer;
pGc.AddElement(pEle, 0);
if (refresh)
{
IActiveView pAv = pMapCtrl.ActiveView;
pAv.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
}
#endregion #region 绘制polyline
/// <summary>
///
/// </summary>
/// <param name="pPolyline"></param>
/// <param name="pLineSym"></param>
/// <param name="pMapCtrl"></param>
/// <param name="refresh"></param>
public static void DrawPolyline(IPolyline pPolyline, ISimpleLineSymbol pLineSym, IMapControl2 pMapCtrl,
bool refresh)
{
ILineElement pLineEle = new LineElementClass();
IElement pEle = pLineEle as IElement;
pLineEle.Symbol = pLineSym;
pEle.Geometry = pPolyline; IGraphicsContainer pGc = pMapCtrl.Map as IGraphicsContainer;
pGc.AddElement(pEle, 0);
if (refresh)
{
IActiveView pAv = pMapCtrl.ActiveView;
pAv.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
}
#endregion #region 绘制点
/// <summary>
/// 绘制点
/// </summary>
/// <param name="pnt"></param>
/// <param name="pMapCtrl"></param>
/// <param name="pColor">颜色</param>
/// <param name="refresh">是否刷新</param>
public static void DrawPoint(IPoint pnt, IMapControl2 pMapCtrl, IRgbColor pColor, bool refresh)
{
ISimpleMarkerSymbol pMarkerSymbol = new SimpleMarkerSymbolClass(); pMarkerSymbol.Color = pColor;
pMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;
pMarkerSymbol.Size = 3;
IElement pEle;
IMarkerElement pMe = new MarkerElementClass();
pMe.Symbol = pMarkerSymbol;
pEle = pMe as IElement;
pEle.Geometry = pnt; IActiveView pav = pMapCtrl.ActiveView;
IGraphicsContainer pGc = pMapCtrl.Map as IGraphicsContainer;
pGc.AddElement(pEle, 0);
if (refresh)
pav.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
#endregion