IEditTask task = (this._editor as IEditTaskSearch).get_TaskByUniqueName("GarciaUI_CreateNewFeatureTask");
 this._editor.CurrentTask = task;

IEditTaskSearch:    Provides access to members that find edit tasks by name.

常见的EditTask及其名称:(From帮助文档)

IEditLayers: Provides access to members that control information about layers in the edit session. 

The IEditLayers interface exposes members for setting and getting the editor‘s current layer and current subtype. The current layer (or target layer) determines which layer will contain newly created features. For instance, if you set the target layer to ‘Buildings‘, any new features created will be part of the Buildings layer. Edit tasks and commands that create new features use this property to determine which layer to write out the new features to. For example, the ‘Create New Features‘ task and the ‘Union‘ command both create new features in the target layer.

说明:IEditLayers接口用于管理编辑会话期间的图层

可以用来获取或设置编辑器的当前图层或subtype(不知为何物),当前图层决定了哪个图层用于新建要素

三.

if (this._lineFeedback == null)
    {
        this._lineFeedback = new NewTextBezierCurveFeedbackClass();
        this._lineFeedback.Display = this._editor.Display;
        this._lineFeedback.Start(this._mousePoint, this._editor.Map.ReferenceScale);
    }
    else
    {
        this._lineFeedback.AddPoint(this._mousePoint);
    }

INewLineFeedback: Provides access to members that control the new line display feedback. 

The NewLineFeedback coclass allows the user to form a new Polyline geometry on the display. While the feedback is being used, the line shown on the screen is a series of segments made up of straight lines between each of the points clicked by the user. If the user opts to add no intermediate vertices, that is, they simply click at the start point (Start), move the mouse (MoveTo), and double-click at the end (AddPoint and Stop), then a polyline with only one segment will be generated.

同上,还有其他很多INew***Feedback接口与对象,可以实现辅助绘制功能

 ISnapEnvironment environment = this._editor as ISnapEnvironment;
    if (this._mousePoint != null)
    {
        this._editor.InvertAgent(this._mousePoint, 0);
    }
    this._mousePoint = this._editor.Display.DisplayTransformation.ToMapPoint(arg.X, arg.Y);
    if (KeyboardInfo.GetKeyState(Keys.Space).IsPressed)
    {
        environment.SnapPoint(null);
    }
    else
    {
        environment.SnapPoint(this._mousePoint);
    }
    this._editor.InvertAgent(this._mousePoint, 0);
    if (this._lineFeedback != null)
    {
        this._lineFeedback.MoveTo(this._mousePoint);
    }