1. spot

IMarkerElement pMarkerElement = new MarkerElementClass();
pMarkerElement.Symbol.Color = TransColorToAEColor(geoColor);
var pElement = pMarkerElement as IElement;
pElement.Geometry = pubGeometry;
var g = mapcontrol.ActiveView.GraphicsContainer;
g.AddElement(pElement, 0);
mapcontrol.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);

2. Line

ISimpleLineSymbol pSimpleLineSymbol = new SimpleLineSymbolClass();
pSimpleLineSymbol.Color = TransColorToAEColor(geoColor);
pSimpleLineSymbol.Width = 2;
var pLineElement = new LineElementClass();
pLineElement.Symbol = pSimpleLineSymbol;
var element = pLineElement as IElement;
IRubberBand pRubberBand;
pRubberBand = new RubberLineClass();
element.Geometry = pubGeometry;
var g = mapcontrol.ActiveView.GraphicsContainer;
g.AddElement(element, 0);
mapcontrol.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);

3. Noodles

The code for drawing polygons on the map is as follows ：

 // Simple fill patterns and colors 
 ISimpleFillSymbol pFillSymbol = new SimpleFillSymbol();
 pFillSymbol.Style = esriSimpleFillStyle.esriSFSSolid;
 pFillSymbol.Color = TransColorToAEColor(Color.LightGray);
 pFillSymbol.Style = esriSimpleFillStyle.esriSFSBackwardDiagonal;
 // Set the fill feature 
 IFillShapeElement pPolygonEle = new PolygonElementClass();
 pPolygonEle.Symbol = pFillSymbol;
 // determine Geometry attribute 
 IElement pEle = pPolygonEle as IElement;
 pEle.Geometry = polygon;          
 var g = mapcontrol.ActiveView.GraphicsContainer;
 g.AddElement(pEle, 0);
 mapcontrol.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);

Envelop The rectangle is drawn as follows ：

ISimpleFillSymbol simpleFillsymbol = new SimpleFillSymbolClass();
IRgbColor color = new RgbColorClass();
color.RGB=0;
simpleFillsymbol.Outline.Color = color;
simpleFillsymbol.Outline.Width = 1;
simpleFillsymbol.Style = esriSimpleFillStyle.esriSFSHollow;
IFillShapeElement rectElemnt = new RectangleElementClass();
rectElemnt.Symbol = simpleFillsymbol;
var element = rectElemnt as IElement;
element.Geometry = env;
g.AddElement(element, 0);

（1）pFillSymbol.Style = esriSimpleFillStyle.esriSFSSolid

（ Default fill method ）
Solid fill.

（2）pFillSymbol.Style = esriSimpleFillStyle.esriSFSNull

Empty fill.

（3）pFillSymbol.Style = esriSimpleFillStyle.esriSFSHollow

Hollow fill (same as esriSFSNull).

（4）pFillSymbol.Style = esriSimpleFillStyle.esriSFSHorizontal

Horizontal hatch fill ------.

（5）pFillSymbol.Style = esriSimpleFillStyle.esriSFSVertical

Vertical hatch fill ||||||.

（6）pFillSymbol.Style = esriSimpleFillStyle.esriSFSForwardDiagonal

45-degree downward, left-to-right hatch fill \.

（7）pFillSymbol.Style = esriSimpleFillStyle.esriSFSBackwardDiagonal;

45-degree upward, left-to-right hatch fill //.

（8）pFillSymbol.Style = esriSimpleFillStyle.esriSFSCross

Horizontal and vertical crosshatch ++++++.

（9）pFillSymbol.Style = esriSimpleFillStyle.esriSFSDiagonalCross

45-degree crosshatch xxxxxx.

4. written words

var pTextElement = new TextElementClass();
var pFont = (IFontDisp)new StdFont();
pFont.Bold = true;
pFont.Name = " Song style ";
pFont.Size = 10;
var pColor = new RgbColorClass();
pColor.RGB = 0;
var pTextSymbol = new TextSymbolClass();
pTextSymbol.Color = pColor;
pTextSymbol.Font = pFont;
pTextElement.Text = text;
pTextElement.Symbol = pTextSymbol;
var pElement = (IElement)pTextElement;
pElement.Geometry = point;
var g = mapcontrol.ActiveView.GraphicsContainer;
g.AddElement(pElement, 0);
 mapcontrol.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);