Changing Layer Color

Question

I have a map with many feature classes on it. I want to use arcobjects to get to a selected layer (aka one of the feature classes) on the map, and change the fill color of all the polygons within that feature class. I don't want to add anymore features or make a new feature class, just change the colors of existing ones. I want to make this a user inputted color, so I want to use the color dialog in VS2013.

I've read that IGraphicsContainer is a useful interface to implement, but I don't know how to do that.

ILayerDescription layerdes = (ILayerDescription)featlayer;
layerdes.SelectionColor = colorDialog1.Color;

Implementing code with these lines gave me the error: Cannot implicitly convert type 'System.Drawing.Color' to 'ESRI.ArcGIS.Display.IColor'

Answer 1

Convert the .NET color object from the color dialog to an IColor first using the RGB components first. Passing the color properties to a method like this should do it:

public IColor GetColor(int pRed, int pGreen, int pBlue)
    {
        IRgbColor rgb = new RgbColorClass();
        rgb.Red = pRed;
        rgb.Green = pGreen;
        rgb.Blue = pBlue;
        return (IColor)rgb;
    }

Answer 2

```CS

    IFeatureClass featureClass = null;
    IObjectClass objectClass = feature.Class;
    featureClass = objectClass as IFeatureClass; 

    IGeoFeatureLayer layer = featureLayer as IGeoFeatureLayer;
    IFeatureRenderer featureRenderer = layer.Renderer;
    ISymbol symbol = null;


    if (featureRenderer is IUniqueValueRenderer)
    {
        IUniqueValueRenderer uniqueValueRenderer = featureRenderer as IUniqueValueRenderer;
        symbol = uniqueValueRenderer.DefaultSymbol;
    }
    if (featureRenderer is ISimpleRenderer)
    {
        ISimpleRenderer simpleRender = featureRenderer as ISimpleRenderer;
        symbol = simpleRender.Symbol;
    } ```