ArcEngine-圖層簡單渲染顏色隨機問題

C#Random類生成僞隨機數，高頻率使用會導致生成相同的隨機序列。爲避免渲染的圖層的顏色一樣，每次生成顏色需要使用不同的種子。

        private static int m_RandomSeed = 0;
        private static int RandomSeed
        {
            get
            {
                m_RandomSeed++;
                if (m_RandomSeed == int.MaxValue)
                    m_RandomSeed = 0;

                return m_RandomSeed % 20;
            }
        }


        public void AddLayer(IMap TargetMap, IFeatureClass AddFeaCls, string LayerName = "",
            bool IsSimpleRender = false, string DisplayField = "", bool IsLable = false)
        {
            IFeatureLayer pFeaLayer = new FeatureLayerClass();
            pFeaLayer.FeatureClass = AddFeaCls;
            pFeaLayer.Name = string.IsNullOrEmpty(LayerName) ? AddFeaCls.AliasName : LayerName;
            if (IsSimpleRender && AddFeaCls.ShapeType == ESRI.ArcGIS.Geometry.esriGeometryType.esriGeometryPolygon)
            {
                ISimpleRenderer simpleRender = new SimpleRenderer();
                ISymbol result = new ESRI.ArcGIS.Display.SimpleFillSymbolClass();
                (result as ISimpleFillSymbol).Style = esriSimpleFillStyle.esriSFSHollow;
                ISimpleLineSymbol outline = new SimpleLineSymbolClass();
                outline.Width = 1;
                int seed = RandomSeed;        // 獲取種子
                Random colorRandom = new Random(seed);
                outline.Color = new RgbColorClass() { RGB = colorRandom.Next(256) * 65536 + colorRandom.Next(256) * 256 + colorRandom.Next(256) } as IColor;

                (result as ISimpleFillSymbol).Outline = outline;
                simpleRender.Symbol = result;
                (pFeaLayer as IGeoFeatureLayer).Renderer = simpleRender as IFeatureRenderer;
            };

            if (!string.IsNullOrEmpty(DisplayField))
            {
                IGeoFeatureLayer pGeoLayer = pFeaLayer as IGeoFeatureLayer;
                pGeoLayer.DisplayField = DisplayField;
                pGeoLayer.DisplayAnnotation = IsLable;
            }

            TargetMap.AddLayer(pFeaLayer);
        }

 

不使用seed：

使用seed：