void mCtrl_OnMouseDown(object sender, ESRI.ArcGIS.Controls.IMapControlEvents2_OnMouseDownEvent e)

        {

            #region 框选

            

            

            if (e.button == 4)

            {

                IEnvelope pEnvelope = mCtrl.TrackRectangle();  // 通过鼠标，取得一个包络线对象

                ISelectionEnvironment pSelectionEnv = new SelectionEnvironmentClass();  // 设置一个新环境

                pSelectionEnv.DefaultColor = MapHelper.GetRGBColor(Color.Red);     // 再改变原来要素的眼神值

                mCtrl.Map.SelectByShape(pEnvelope, pSelectionEnv, false);

                mCtrl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, null, null);

                ISelection selection = mCtrl.Map.FeatureSelection;

                IEnumFeatureSetup enumFeatureSetup = selection as IEnumFeatureSetup;    //这里很必要

                enumFeatureSetup.AllFields = true;                                      //这里很必要

                IEnumFeature enumFeature = enumFeatureSetup as IEnumFeature;

                enumFeature.Reset();

                IFeature feature = enumFeature.Next();

                IFeatureLayer pFeatureLayer = (IFeatureLayer)mCtrl.get_Layer(currentLayerIndex);

                IFeatureClass pFeatureClass = (IFeatureClass)pFeatureLayer.FeatureClass;

                int fLCDIdx = pFeatureClass.FindField(fieldName);

                lbFields.Items.Clear();

                while (feature != null)

                {

                    var _lcd = feature.get_Value(fLCDIdx);

                    long lcd = Convert.ToInt64(_lcd);

                    lbFields.Items.Add(lcd);

                    feature = enumFeature.Next();

                }

            }

            

            #endregion

            mCtrl.Refresh(esriViewDrawPhase.esriViewForeground, Type.Missing, Type.Missing);

        }