基于插件技术的GIS应用框架（C# + ArcEngine9.3）(五)

基于插件技术的GIS应用框架（C# + ArcEngine9.3）(五)
--------------------------插件初始化（1）
在第四节中，我们论及了插件的XML保存格式，对于各个XML节点的属性也有了一个大概的了解，下面，我们就如何利用DevExpress套件就这些插件的加载进行详细的剖析。首先，我们必须从已经编译好的DLL中获取插件的类型信息，这就需要利用C#所提供的反射机制。
一、插件的反射
/// 根据反射机制产生插件对象并将其放入插件池
public class PluginActivator
{
/// 定义插件文件所在路径
private static readonly string pluginpath = System.Windows.Forms.Application.StartupPath;
/// 获取插件并加入到插件池
public static PluginCollection ActivatePluginsFromDll()
{
//存储插件的容器
PluginCollection _PluginCol = new PluginCollection();
//获得插件文件夹中的每一个dll文件
string[] _files = Directory.GetFiles(pluginpath, "*.dll");
foreach (string _pluginfile in _files)
{
Assembly _assembly = Assembly.LoadFrom(_pluginfile );
if (_assembly != null)
{
Type[] _types = null;
try
{
_types = _assembly.GetTypes();
}
catch (ReflectionTypeLoadException ex)
{
}
finally
{
foreach (Type _type in _types)
{
//获得一个插件对象的接口信息
Type[] _InterfaceList = _type.GetInterfaces();
//遍历接口
foreach (Type InterfaceType in _InterfaceList)
{
//将插件添加到相应的插件池中
switch (InterfaceType.FullName)
{
case "AxeMap.PluginEngine.Interface.IAxCommand":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxTool":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxEdit":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxCombobox":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxColorPicker":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxSubItem":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxMenuDef":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxToolBarDef":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxContentsView":
GetPlugin(_PluginCol, _type);
break;
case "AxeMap.PluginEngine.Interface.IAxDockableWindowDef":
GetPlugin(_PluginCol, _type);
break;
default:
break;
}
}
}
}
}
}
return _PluginCol;
}
/// 提取插件
private static void GetPlugin(PluginCollection pluginColl, Type _type)
{
IAxPlugin plugin = null;
try
{
//创建插件实例
plugin = System.Activator.CreateInstance(_type) as IAxPlugin;
//MessageBox.Show(_type.ToString());
}
catch (Exception ex)
{
}
finally
{
if (plugin != null)
{
if (!pluginColl.Contains(plugin))
{
pluginColl.Add(plugin);
}
}
}
}
}
关于如何反射对象，C#提供了很多的例子，具体就不再叙述，下面我们将结合DevExpress套件重点介绍各类插件的加载过程。
二、插件的初始化
1.Command插件
private DevExpress.XtraBars.BarButtonItem CreateUICommand(IAxCommand cmd, string itemnamespace, string customcaption)
{
if (cmd == null)
{
return null;
}
(cmd as ICommand).OnCreate(_App); //调用esriSystemUI.ICommand插件的OnCreate,将框架对象传递给插件对象
BarButtonItem UICmd = new BarButtonItem(); //产生一个UI层的按钮对象，并根据插件的属性进行相应设置
UICmd .Hint = (cmd as ICommand).Tooltip;
if (customcaption != "")
{
UICmd .Caption = customcaption; //优先显示插件配置文件中插件的标题
}
else
{
UICmd .Caption = (cmd as ICommand).Caption;
}
//加载命令插件的bitmap或icon
System.IntPtr _Handle = (System.IntPtr)(cmd as ICommand).Bitmap;
if (_Handle.ToInt32() != 0)
{
try
{
UICmd .Glyph = System.Drawing.Bitmap.FromHicon(_Handle);
}
catch
{
UICmd.Glyph = System.Drawing.Image.FromHbitmap(_Handle);
}
}
UICmd.Enabled = (cmd as ICommand).Enabled;
if ((cmd as ICommand).Checked)
{
UICmd .ButtonStyle = BarButtonStyle.Check;
}
//记录命令插件的类型到 Tag 属性
UICmd.Tag = cmd.ToString();
//记录命令插件的Category属性，由于使用DevExpress，设置UICmd的分类很麻烦，这是DevExpress的不好用的地方
IEnumerator categoryEnum = _barManager.Categories.GetEnumerator();
string cmdCategory;
categoryEnum.Reset();
while (categoryEnum.MoveNext() == true)
{
cmdCategory = ((BarManagerCategory)categoryEnum.Current).ToString();
if (cmdCategory == (cmd as ICommand).Category)
{
UICmd.Category = (BarManagerCategory)categoryEnum.Current;
break;
}
}
//委托事件
UICmd.ItemClick += new ItemClickEventHandler(UICmd_Click);
//将生成的UICmd添加到CommandManager中，DevExpress提供一个统一管理器，管理所有的工具条对象
_barManager.Items.AddRange(new DevExpress.XtraBars.BarItem[] { UICmd});
_UIControlList.Add(itemnamespace, UICmd);
return UICmd;
}
2.ICombobox插件(以编辑任务列表为例)
编辑任务列表的插件实现：
using System;
using System.Collections.Generic;
using System.Text;
using AxeMap.AxeMap;
using AxeMap.PluginEngine.Interface;
using AxeMap.AxeMapEngine.Interface;
using AxeMap.AxeMapEngine.Implement;
namespace AxeMap.MapEdit
{
public class EditTasks : IAxCombobox
{
private AxeMapEngine.Interface.IAxApplication _App;
private string _EditTask;
private List<string> _EditTaskList = null;
public EditTasks()
{
_EditTaskList = new List<string>();
_EditTaskList.Add("新建要素");
_EditTaskList.Add("分割要素");
_EditTaskList.Add("自动闭合多边形");
}
#region IAxCombobox 成员
public string Name
{
get { return "EditTasks"; }
}
public string Caption
{
get { return "编辑任务"; }
}
public bool ShowCaption
{
get { return true; }
}
public System.Collections.ICollection Items
{
get { return _EditTaskList; }
}
public string Text
{
get
{
if (_App.MapEngine.IsBeingEdited)
{
return _EditTask;
}
else
{
return "";
}
}
}
public string Category
{
get { return "编辑"; }
}
public bool Enabled
{
get
{
return ((_App.MapEngine.IsBeingEdited) && (_App.MapEngine.CurrentFeatureLayer != null));
}
}
public bool Editable //用户只能从列表中选择，不能修改列表
{
get { return false; }
}
public int Width //列表显示多宽
{
get { return 186; }
}
public int DropDownRows
{
get { return 9; }
}
public string Tooltip
{
get { return "编辑任务"; }
}
public string Message
{
get { return "编辑任务"; }
}
public void OnKeyPress()
{

}
public void OnKeyDown()
{
}
public void EditValueChanged(string newText)
{
_EditTask = newText;
if (_EditTask == "")
{
_App.MapEngine.CurrentEditTask = null;
}
else
{
_App.MapEngine.CurrentEditTask = null;
switch (_EditTask)
{
case "": _App.MapEngine.SetEditTask(""); break;
case "新建要素": _App.MapEngine.SetEditTask("Create New Feature"); break;
case "分割要素": _App.MapEngine.SetEditTask("Cut Features"); break;
case "自动闭合多边形": _App.MapEngine.SetEditTask("Auto Complete Polygon"); break;
default: _App.MapEngine.SetEditTask("Create New Feature"); break;
}
}
}
private void WorkspaceEvents_OnStartEditing()
{
_EditTask = _EditTaskList.ToArray().GetValue(0).ToString();
EditValueChanged(_EditTask);
}
private void WorkspaceEvents_OnStopEditing(bool bSave)
{
_EditTask = "";
EditValueChanged(_EditTask);
}
public void OnCreate(AxeMapEngine.Interface.IAxApplication hook)
{
if (hook != null)
{
this._App = hook; //获取框架程序对象
_App.MapEngine.WorkspaceEvents.OnStartEditing += new AxWorkspaceStartEditingEventsHandler(WorkspaceEvents_OnStartEditing); //通过事件代理响应框架中当前编辑工作空间的事件
_App.MapEngine.WorkspaceEvents.OnStopEditing += new AxWorkspaceStopEditingEventsHandler(WorkspaceEvents_OnStopEditing);
}
}
#endregion
}
}