用keyword实现Editor.GetSelection的退出功能

有时候我们在使用GetSelection功能让用户选择实体时，可能会给用户提供一些keyword选项，要接收用户选择的keyword选项，需要用到PromptSelectionOptions.KeywordInput事件。

但是，有时为了有时在用户选择了某个keyword项时，需要结束GetSelection主操作（这样体验性更好，用户更方便），但是一直没有找到解决的办法，试了好多方法都以失败告终。

今天，有一个功能又需要实现这一点，于是在群里问了一句，胖子说他QQ空间里有，于是进去一看，晃然大悟：在keywordInput事件里抛出一个异常即可。

[CommandMethod("SELKW")]
publicvoid GetSelectionWithKeywords()
{
    Document doc =
        Application.DocumentManager.MdiActiveDocument;
    Editor ed = doc.Editor;

    // Create our options object
    PromptSelectionOptions pso = newPromptSelectionOptions();

    // Add our keywords
    pso.Keywords.Add("FIrst");
    pso.Keywords.Add("Second");

    // Set our prompts to include our keywords
    string kws = pso.Keywords.GetDisplayString(true);
    pso.MessageForAdding =
                "\nAdd objects to selection or " + kws;
    pso.MessageForRemoval =
            "\nRemove objects from selection or " + kws;

    pso.KeywordInput +=
           newSelectionTextInputEventHandler(pso_KeywordInput);

    PromptSelectionResult psr = null;
    try
    {
        psr = ed.GetSelection(pso);

        if (psr.Status == PromptStatus.OK)
        {
            //your logic
        }
    }
    catch (System.Exception ex)
    {
        if (ex is Autodesk.AutoCAD.Runtime.Exception)
        {
            Autodesk.AutoCAD.Runtime.Exception aEs =
                    ex as Autodesk.AutoCAD.Runtime.Exception;

            //user has pressed keyword.

            if (aEs.ErrorStatus ==
                        Autodesk.AutoCAD.Runtime.ErrorStatus.OK)
            {
                ed.WriteMessage("\nKeyword entered: {0}",
                                                     ex.Message);
            }
            else
            {
                //other exception, please handle
            }
        }
    }

}
void pso_KeywordInput(object sender, SelectionTextInputEventArgs e)
{
    //user has pressed keyword, so throw Exception
    throw new Autodesk.AutoCAD.Runtime.Exception(
                Autodesk.AutoCAD.Runtime.ErrorStatus.OK, e.Input);
}

用keyword实现Editor.GetSelection的退出功能