How to change feature color?

Question

I have feature (polygon) was gotten by spatial query from the map.

How to change its color?

I used this code but it didn't work

IMxDocument mxDocument = application.Document as IMxDocument;
IActiveView activeView = mxDocument.ActiveView;
IRgbColor rgbColor = new RgbColorClass();
ISimpleFillSymbol fillSymbol = new SimpleFillSymbolClass();
IElement element = new PolygonElementClass();
rgbColor.Red = 255;
rgbColor.Green = 40;
rgbColor.Blue = 50;
fillSymbol.Color = rgbColor;
element.Geometry = parcel.Shape;
IFillShapeElement pFillElement = (IFillShapeElement)element;
pFillElement.Symbol = fillSymbol;
activeView.Refresh();

Answer 1

I resolved this issue by using IGraphicsContainer see this link

Answer 2

My workflow for "re-coloring" features is as follows:

First i setup the layer to be symbolized by categories, and set the correct options, classes, etc. with the normal ArcGIS workflow.

Then I use scripting to set the value of the field the data is colored with to my wanted value.

I use this for a national grid where i want to highlight certain grid cells. The feature class/shapefile is symbolized on the field "selected", displayed as grey when selected=0 and as yellow when selected=1. Then its simply (in python):

with arcpy.da.UpdateCursor(<shapefile to update>, ("ID","selected")) as cursor:
  for data_row in cursor:
    if data_row[0] <should be set to selected>:
      data_row[1] = 1
    else:
      data_row[1] = 0
    cursor.updateRow(data_row)

Answer 3

You need to add your element to a graphics layer. See this sample from ESRI.

Dim pCGLayer As ICompositeGraphicsLayer
Set pCGLayer = New CompositeGraphicsLayer

'Name the new graphics layer
Dim pLayer As ILayer
Set pLayer = pCGLayer
pLayer.Name = "TestPoint"

'Add the layer to the map
pMap.AddLayer pCGLayer

'Get the graphics layer and screen display
Dim pGrLayer As IGraphicsLayer
Set pGrLayer = pCGLayer

Dim pScreenDisplay As IScreenDisplay
Set pScreenDisplay = pMxApp.Display

'Add the marker element ot the layer graphics container
Dim pGraphicCont As IGraphicsContainer
Set pGraphicCont = pGrLayer
pGraphicCont.AddElement pMarkerElement, 0
With pScreenDisplay
  .ActiveCache = 0
  .StartDrawing pScreenDisplay.hDC, 0
  .SetSymbol pSimpleMarkerSymbol
  pElement.Draw pScreenDisplay, Nothing
  .FinishDrawing
End With

'Refresh/redraw the display with the new point
pMxDoc.ActiveView.Refresh

http://support.esri.com/en/knowledgebase/techarticles/detail/21613

Answer 4

ESRI.ArcGIS.Display.IColor rgbColor = new ESRI.ArcGIS.Display.RgbColorClass(); rgbColor.RGB = 255;

ESRI.ArcGIS.Display.IMarkerSymbol markerSymbol = (ESRI.ArcGIS.Display.IMarkerSymbol)simpleMarker3DSymbol; // Explicit cast markerSymbol.Color = rgbColor; markerSymbol.Size = 100000;

Answer 5

[Visual Basic 6.0]

Dim aColor As IRGBColor 
Set aColor = New RGBColor 

aColor.Red = 133 
aColor.Green = 135 
aColor.Blue = 43 
aColor.Transparency = 50