ArcGIS Engine控件编程(8)

using System; using System.Drawing;

using System.Runtime.InteropServices; using ESRI.ArcGIS.ADF.BaseClasses; using ESRI.ArcGIS.Controls; using ESRI.ArcGIS.Carto; namespace AppGIS1 {

public sealed class ClearFeaSele : BaseCommand {

private IHookHelper m_hookHelper;

public ClearFeaSele() {

//改变继承类的属性

base.m_category = \; base.m_caption = \清除当前地图选择要素\; base.m_message = \清除当前地图选择要素\; base.m_toolTip = \清除当前地图选择要素\; base.m_name = \清除当前地图选择要素\; try {

//设置命令的图标

string bitmapResourceName = GetType().Name + \; base.m_bitmap = new Bitmap(GetType(), bitmapResourceName); }

catch (Exception ex) {

System.Diagnostics.Trace.WriteLine(ex.Message, \); } }

#region Overriden Class Methods

public override void OnCreate(object hook) {

if (hook == null) return;

if (m_hookHelper == null)

m_hookHelper = new HookHelperClass(); //将mapControl作为钩子传递 m_hookHelper.Hook = hook; }

public override void OnClick() {

m_hookHelper.FocusMap.ClearSelection();

//获取焦点地图的IActiveView接口

IActiveView pActiveView = (IActiveView)m_hookHelper.FocusMap; pActiveView.Refresh(); }

#endregion } }

2.6.3 自定义开发工具

自定义工具的开发需继承基类BaseTool，在类的构造函数中，需对自定义工具进行初始化。因工具需要鼠标与地图类控件（MapControl、PageLayoutControl等）进行交互，以完成某个特定功能。除需重写OnCreate()方法外，还要根据具体情况重写其它方法，如OnMouseDown()、OnMouseMove()和OnMouseUp()等。下例通过开发实现地图缩小的ZoomOut工具进行举例说明。基本步骤如下：

（1）建立新类MapZoomOutTool，需要继承BaseTool基类，如下图所示。在随后弹出的对话框中仍然选择MapControl or PageLayoutControl Tool选项。

图 自定义工具类继承BaseTool基类

（2）在类中需要判断用户是点击缩小还是拉框缩小，具体实现代码如下：

using System.Runtime.InteropServices; using ESRI.ArcGIS.ADF.CATIDs; using ESRI.ArcGIS.Carto; using ESRI.ArcGIS.Controls; using ESRI.ArcGIS.esriSystem; using ESRI.ArcGIS.Geometry; using ESRI.ArcGIS.ADF.BaseClasses; using ESRI.ArcGIS.ADF; using ESRI.ArcGIS.Display;

public sealed class MapZoomOutTool : BaseTool {

private INewEnvelopeFeedback m_feedBack; private IPoint m_point; private Boolean m_isMouseDown;

private IHookHelper m_HookHelper = new HookHelperClass(); public MapZoomOutTool() {

//设置command属性 base.m_caption = \缩小\; base.m_message = \缩小\; base.m_toolTip = \缩小\; base.m_name = \缩小\;

base.m_category = \;

base.m_bitmap = new System.Drawing.Bitmap(string.Format(\软件开发统一图标\\\\ForStockIcon\\\\ZoomOut.bmp\,Application.StartupPath));

base.m_cursor = new System.Windows.Forms.Cursor(string.Format(\软件开发统一图标\\\\ForStockIcon\\\\ZoomOut.cur\,Application.StartupPath)); }

public override void OnCreate(object hook) {

m_HookHelper.Hook = hook; }

public override bool Enabled { get {

if (m_HookHelper.FocusMap == null) return false; return true; } }

public override void OnMouseDown(int button, int shift, int x, int y) {

if (m_HookHelper.ActiveView == null) return; //如果是视图

if (m_HookHelper.ActiveView is IActiveView) {

//图上创建一个点 IPoint pPoint =

(IPoint)m_HookHelper.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y); //得到地图框

IMap pMap = m_HookHelper.ActiveView.HitTestMap(pPoint); if (pMap == null) return;

if (pMap != m_HookHelper.FocusMap)

{

m_HookHelper.ActiveView.FocusMap = pMap;

m_HookHelper.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null); } }

//在焦点图上创建一个点

IActiveView pActiveView = (IActiveView)m_HookHelper.FocusMap;

m_point = pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y); m_isMouseDown = true; }

public override void OnMouseMove(int button, int shift, int x, int y) {

if (!m_isMouseDown) return; //得到焦点图

IActiveView pActiveView = (IActiveView)m_HookHelper.FocusMap; //初始一个范围

if (m_feedBack == null) {

m_feedBack = new NewEnvelopeFeedbackClass(); m_feedBack.Display = pActiveView.ScreenDisplay; m_feedBack.Start(m_point); }

base.m_cursor = new System.Windows.Forms.Cursor(string.Format(\软件开发统一图标\\\\ForStockIcon\\\\MoveZoomOut.cur\,Application.StartupPath)); //画范围

m_feedBack.MoveTo(pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y)); }

public override void OnMouseUp(int button, int shift, int x, int y) {

base.m_cursor = new System.Windows.Forms.Cursor(string.Format(\软件开发统一图标\\\\ForStockIcon\\\\ZoomOut.cur\,Application.StartupPath)); if (!m_isMouseDown) return; IEnvelope pEnvelope; IEnvelope pFeedEnvelope; double newWidth, newHeight; //得到焦点图

IActiveView pActiveView = (IActiveView)m_HookHelper.FocusMap; //如果不画范围

if (m_feedBack == null) {

//点击缩小当前范围

pEnvelope = pActiveView.Extent; pEnvelope.Expand(1.5, 1.5, true); pEnvelope.CenterAt(m_point);

} else {

//停止画框

pFeedEnvelope = m_feedBack.Stop();

if (pFeedEnvelope.Width == 0 || pFeedEnvelope.Height == 0) {

m_feedBack = null; m_isMouseDown = false; }

newWidth = pActiveView.Extent.Width * (pActiveView.Extent.Width / pFeedEnvelope.Width);

newHeight = pActiveView.Extent.Height * (pActiveView.Extent.Height / pFeedEnvelope.Height);

//建立新的范围坐标

pEnvelope = new EnvelopeClass();

pEnvelope.PutCoords(pActiveView.Extent.XMin - ((pFeedEnvelope.XMin - pActiveView.Extent.XMin) * (pActiveView.Extent.Width / pFeedEnvelope.Width)), pActiveView.Extent.YMin - ((pFeedEnvelope.YMin - pActiveView.Extent.YMin) * (pActiveView.Extent.Height / pFeedEnvelope.Height)), (pActiveView.Extent.XMin - ((pFeedEnvelope.XMin -

pActiveView.Extent.XMin) * (pActiveView.Extent.Width / pFeedEnvelope.Width))) + newWidth, (pActiveView.Extent.YMin - ((pFeedEnvelope.YMin -

pActiveView.Extent.YMin) * (pActiveView.Extent.Height / pFeedEnvelope.Height))) + newHeight); }

//建立新的视图范围

pActiveView.Extent = pEnvelope; pActiveView.Refresh(); m_feedBack = null; m_isMouseDown = false; } }

2.6.4 自定菜单开发实例

在ToolbarControl上不仅可以驻留命令和工具，还可以驻留菜单条。要在工具条上驻留菜单条，首先需要实现IMenuDef接口，在工具条上实现菜单功能，还需要将菜单中的所有命令类组织在一个项目文件（DLL）中，再在其它项目中添加该项目的引用。下面通过举例，将地图符号化的6个命令类和实现IMenuDef接口的类SymbologyMenu组织在一个项目Symbology中。

本实例将自定义下拉菜单和六种符号化的方法封装在了一个DLL中，并在新建的工程中引用封装好的DLL，具体步骤如下：

（1）新建DLL文件。打开VS2008，选择新建项目对话框中的“类库”，如下图所示，输入一个项目名，点击“确定”。

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