这个系列好久没有更新了，时间拖得太久了，一来是工作确实忙，出差比较多；二来，最近公司有点动荡，部门独立出来成立一个公司，有些其他事情耽搁了；三来，懒。这篇文章将介绍一下图层树，图层树的英文简写是Toc，全程Table of content。
ArcMap的TOC功能很强大，基本上我在实现TOC的时候，也是照虎画猫（我实现的这个和ArcMap比起来就是一只小猫，蛮丑的小猫）。闲话少扯，进入正题。
Toc的功能包括：
1、显示（调整）图层组织结构
2、对图层的显示/隐藏状态进行控制
3、提供针对图层的特殊操作，包括数据导出、选择集管理、属性设置等
Toc控件本身较为简单，继承了UserControl的一个用户自定义控件，增加了图层顺序拖动调整的功能。通过与右键菜单的结合，展示出了丰富的功能。
在实现右键菜单时，首先要获取在Toc中选中的对象类型及状态，比如：如果选中的是FeatureLayer，那就可以进行数据导出、选择集操作，如果选中的FeatureLayer对应的FeatureClass的GeometryType是Polygon，就显示“设置为工作区域”菜单……
要达到这个目的，就需要在Toc控件中对外公开一个当前选中对象的属性—SelectItem。具体的定义如下：
public partial class TocControl : UserControl
{..........#region 属性定义public object BuddyControl{get{return this.axTOCControl1.Buddy;}set{this.axTOCControl1.SetBuddyControl(value);}}/// <summary>/// 获取当前图层/// </summary>public ESRI.ArcGIS.Carto.ILayer CurrentLayer{get{return m_layer;}}private SelectItem selectedItem = null;/// <summary>/// 当前选中的对象/// </summary>public SelectItem SeletedItem{get{return this.selectedItem;}}#endregionprivate void GetSelectItem(int x,int y){esriTOCControlItem item = esriTOCControlItem.esriTOCControlItemNone;ILayer layer = null;IBasicMap map = null;this.axTOCControl1.HitTest(x, y, ref item, ref map, ref layer, ref m_other, ref m_index);switch (item){case esriTOCControlItem.esriTOCControlItemLayer:this.selectedItem = new SelectItem(item, layer); break;case esriTOCControlItem.esriTOCControlItemMap:this.selectedItem = new SelectItem(item, map);break;case esriTOCControlItem.esriTOCControlItemLegendClass:this.selectedItem = new SelectItem(item, m_other);break;case esriTOCControlItem.esriTOCControlItemHeading:this.selectedItem = new SelectItem(item, null);break;case esriTOCControlItem.esriTOCControlItemNone:this.selectedItem = null;break;default:this.selectedItem = null;break;}}public class SelectItem{public SelectItem(esriTOCControlItem type,object obj){this.itemType = type;this.itemObject = obj;}private esriTOCControlItem itemType = esriTOCControlItem.esriTOCControlItemLayer;public esriTOCControlItem ItemType{get { return itemType; }set { itemType = value; }}private object itemObject = null;public object ItemObject{get { return itemObject; }set { itemObject = value; }}}..........
}
接下来做的就是需要根据Toc的SelectItem类型进行菜单显示状态控制。大家或许已经猜到了实现方法——使用IConditionEvaluator。没错，在我的框架中，为Toc控件实现了两个ConditionEvaluator，分别是TocItemSelectedConditionEvaluator和LayerFeatureSelectedConditionEvaluator。
TocItemSelectedConditionEvaluator用来判断Toc当前选中对象的具体类型，实现代码：
/// <summary>/// Toc控件选择对象条件计算器/// Toc控件选择对象类型包括：图层:layer,feautrelayer,rasterlayer,grouplayer，地图:map，图例:legend/// wangyuxiang 2010-12-16/// </summary>class TocItemSelectedConditionEvaluator : IConditionEvaluator{public bool IsValid(object caller, Condition condition){if (WorkbenchSingleton.Workbench == null) {return false;}string itemtype = condition.Properties["itemtype"]; GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl tocControl = null;foreach (PadDescriptor pad in WorkbenchSingleton.Workbench.PadContentCollection){if (pad.PadContent != null && pad.PadContent.Control is GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl){tocControl = pad.PadContent.Control as GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl;if (tocControl.SeletedItem != null){if (itemtype == "*"){return true;}if (Convert.ToString(itemtype).ToLower().Equals("layer")){return tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemLayer;}else if (Convert.ToString(itemtype).ToLower().Equals("map")){return tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemMap;}else if (Convert.ToString(itemtype).ToLower().Equals("legend")){return tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemLegendClass;}else if (Convert.ToString(itemtype).ToLower().Equals("featurelayer")){return (tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemLayer && tocControl.SeletedItem.ItemObject is IFeatureLayer);}else if (Convert.ToString(itemtype).ToLower().Equals("rasterlayer")){return (tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemLayer && tocControl.SeletedItem.ItemObject is IRasterLayer);}else if (Convert.ToString(itemtype).ToLower().Equals("grouplayer")){return (tocControl.SeletedItem.ItemType == ESRI.ArcGIS.Controls.esriTOCControlItem.esriTOCControlItemLayer && tocControl.SeletedItem.ItemObject is IGroupLayer);}}break;}}return false;}}
LayerFeatureSelectedConditionEvaluator用来判断当前选中的FeatureLayer是否存在选择集，实现代码：
/// <summary>/// 图层要素选择条件计算器 /// wangyuxiang 2010-12-17/// </summary>class LayerFeatureSelectedConditionEvaluator : IConditionEvaluator{public bool IsValid(object caller, Condition condition){if (WorkbenchSingleton.Workbench == null) {return false;}GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl tocControl = null;foreach (PadDescriptor pad in WorkbenchSingleton.Workbench.PadContentCollection){if (pad.PadContent.Control is GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl){tocControl = pad.PadContent.Control as GISP.Lib.ArcGIS.ArcMap.GUI.MapDisplayBinding.TocControl;if (tocControl.SeletedItem != null){if (tocControl.SeletedItem.ItemObject is IFeatureLayer){IFeatureSelection featureSelection = tocControl.SeletedItem.ItemObject as IFeatureSelection;if (featureSelection != null){ISelectionSet selectionSet = featureSelection.SelectionSet;return (selectionSet != null && selectionSet.Count > 0);}}}break;}}return false;}}
整个右键菜单的Addin配置如下：
<!--二维地图Toc控件右键菜单--><Path name = "/SDF/Pads/ArcMap/TocPad/ContextMenu"><Condition name = "TocItemSelected" itemtype="layer"><MenuItem id = "RemoveLayer"type="ContextMenu"label = "移除"icon="ArcGIS.LayerTreeDelete16"class = "GISP.Addin.ArcMap.Commands.TocCommand_RemoveSelectedLayer"/><MenuItem id = "RemoveLayer"type="ContextMenu"label = "标注"icon="ArcGIS.LayerTreeDelete16"class = "GISP.Addin.ArcMap.Commands.TocCommand_ShowLayerLabel"/><ComplexCondition><And><Condition name = "TocItemSelected" itemtype="featurelayer" action="Disable"/></And><MenuItem id = "ZoomToLayer"type="ContextMenu"label = "查看属性表"icon ="ArcGIS.LayerTableOpen16"class = "GISP.Addin.ArcMap.Commands.TocCommand_ShowLayerAttribute"/></ComplexCondition><MenuItem id = "ZoomToLayer"type="ContextMenu"label = "缩放到图层"icon="GIS.MapControl.FullScreen"class = "GISP.Addin.ArcMap.Commands.TocCommand_ZoomToSelectedLayer"/><ComplexCondition><And><Condition name = "MapScaleOutOfLayerScale" action="Disable"/></And><MenuItem id = "ZoomToVisible"type="ContextMenu"label = "缩放到图层显示比例尺"class = "GISP.Addin.ArcMap.Commands.TocCommand_ZoomToShowLayer"/></ComplexCondition><ComplexCondition><And><Condition name = "TocItemSelected" itemtype="featurelayer" action="Disable"/></And><MenuItem id = "LayerSection" label = "选择集" type ="Menu"><ComplexCondition><And><Condition name = "LayerFeatureSelected" action="Disable"/></And><MenuItem id = "ZoomToSection"type="ContextMenu"label = "缩放到选中要素"icon="ArcGIS.ScreenPosition16"class = "GISP.Addin.ArcMap.Commands.TocCommand_ZoomToSelectedFeatures"/><MenuItem id = "PanToSection"type="ContextMenu"label = "移动到选中要素"class = "GISP.Addin.ArcMap.Commands.TocCommand_PanToSelectedFeatures"/><MenuItem id = "ClearSelectFeatures"type="ContextMenu"label = "取消选中状态"class = "GISP.Addin.ArcMap.Commands.TocCommand_ClearFeaturelayerSelection"/><MenuItem id = "SwtichSelectFeatures"type="ContextMenu"label = "切换选中状态"class = ""/><MenuItem id = "AddSelectFeaturesToWorkArea"type="ContextMenu"label = "添加到工作区域"class = "GISP.Addin.ArcMap.Commands.TocCommand_SetSelectFeaturesAsWorkAreas"/></ComplexCondition><ComplexCondition><And><Condition name = "WorkAreaIsValid" action="Disable"/></And><MenuItem id = "selectIntersectWIthWorkArea"type="ContextMenu"label = "选择工作区域内要素"icon="ArcGIS.GenericAddGreen16"class = "GISP.Addin.ArcMap.Commands.TocCommand_SelectFeaturesIntersectsWithWorkAreas"/></ComplexCondition><MenuItem id = "SelectAllFeatures"type="ContextMenu"label = "全部选中"class = "GISP.Addin.ArcMap.Commands.TocCommand_SelectAllFeatures"/></MenuItem></ComplexCondition><ComplexCondition><And><Condition name = "TocItemSelected" itemtype="featurelayer" action="Disable"/></And><MenuItem id = "Separator" type = "Separator" /><MenuItem id = "FeatureLayerData"label = "数据"icon="ArcGIS.ContentsWindowDrapedLayers16"type = "Menu"><MenuItem id = "ExportFeatureLayerData" type="ContextMenu" label = "导出" icon="ArcGIS.LayerToLayer16" class = "GISP.Addin.ArcMap.Commands.TocCommand_ExportFeatureLayer"/></MenuItem><MenuItem id = "SetAsWorkArea"type="ContextMenu"label = "设置为工作区域"icon ="ArcGIS.GenericOptions16"class = "GISP.Addin.ArcMap.Commands.WorkArea_SetLayerAsWorkAreaCommand"/><MenuItem id = "Separator" type = "Separator" /></ComplexCondition></Condition><Condition name = "TocItemSelected" itemtype="*"><MenuItem id = "LayerProperties"type="ContextMenu"label = "属性"icon ="ArcGIS.GenericOptions16"class = "GISP.Addin.ArcMap.Commands.TocCommand_ShowTocItemProperty"/></Condition></Path>
至此Toc控件Over，具体的右键菜单功能根据需求进行开发。
