在AutoCAD .Net程序中改变程序的预选择集

using?Autodesk.AutoCAD.ApplicationServices;

using?Autodesk.AutoCAD.DatabaseServices;

using?Autodesk.AutoCAD.EditorInput;

using?Autodesk.AutoCAD.Runtime;
namespace?SelectionTest

{

public?class?PickfirstTestCmds

{

[CommandMethod(“PFA”,?CommandFlags.Modal |

CommandFlags.UsePickSet |

CommandFlags.Redraw)

]

public?void?AddToPickfirstSet()

{

Document?doc =

Application.DocumentManager.MdiActiveDocument;
Editor?ed = doc.Editor;
// First let’s get the initial pickfirst set

PromptSelectionResult?sr =

ed.SelectImplied();
// Create a collection containing the initial set

//? (could have used an array, but a collection is

//? easier in dynamic situations, such as this)

ObjectIdCollection?objs;

if?(sr.Status ==?PromptStatus.OK)

objs =

new?ObjectIdCollection(

sr.Value.GetObjectIds()

);

else

objs =?new?ObjectIdCollection();
// Clear the pickfirst set…

ed.SetImpliedSelection(new?ObjectId[0]);

// …but highlight the objects

if?(objs.Count > 0)

HighlightEntities(objs);
// No ask the user to select objects

sr = ed.GetSelection();

if?(sr.Status ==?PromptStatus.OK)

{

// Add them all to the collection

foreach?(ObjectId?obj?in?sr.Value.GetObjectIds())

{

objs.Add(obj);

}

// Dump the collection to an array

ObjectId[] ids =?new?ObjectId[objs.Count];

objs.CopyTo(ids, 0);
// And finally set the pickfirst set

ed.SetImpliedSelection(ids);

}

}
// Highlight the entities by opening them one by one

private?void?HighlightEntities(ObjectIdCollection?objIds)

{

Document?doc =

Application.DocumentManager.MdiActiveDocument;

Transaction?tr =

doc.TransactionManager.StartTransaction();

using?(tr)

{

foreach?(ObjectId?objId?in?objIds)

{

Entity?ent =

tr.GetObject(objId,?OpenMode.ForRead)

as?Entity;

if?(ent !=?null)

ent.Highlight();

}

}

}

}

}