如何通过选择集仅获取一个acad对象

Question

我在选择目标

acadObject

时遇到了一些麻烦。我通过

selectionset.SelectonScreen

方法获取输入。

在这里，我可以根据我的过滤条件从模型空间中获取更多数量的对象。但我只需要用户提供的一个对象。

我在下面提到了我的代码：

AcadSelectionSet selset= null;
selset=currDoc.selectionset.add("Selset");
short[] ftype=new short[1];
object[] fdata=new object[1];
ftype[0]=2;//for select the blockreference
fdata[0]=blkname;
selset.selectOnScreen ftype,fdata;  // Here i can select any no. of blocks according to filter value but i need only one block reference.

请帮我解决这个问题。

Answer 1

这是来自 AutoCAD 开发人员帮助的直接引用

http://docs.autodesk.com/ACD/2013/ENU/index.html?url=files/GUID-CBECEDCF-3B4E-4DF3-99A0-47103D10DADD.htm,topicNumber=d30e724932

AutoCAD .NET API 有大量文档。

你需要有

[assembly: CommandClass(typeof(namespace.class))]

在命名空间上方，如果您希望能够在

NetLoad

.dll（如果它是类库）之后从命令行调用此命令。

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;

[CommandMethod("SelectObjectsOnscreen")]
public static void SelectObjectsOnscreen()
{
  // Get the current document and database
  Document acDoc = Application.DocumentManager.MdiActiveDocument;
  Database acCurDb = acDoc.Database;

  // Start a transaction
  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
  {
      // Request for objects to be selected in the drawing area
      PromptSelectionResult acSSPrompt = acDoc.Editor.GetSelection();

      // If the prompt status is OK, objects were selected
      if (acSSPrompt.Status == PromptStatus.OK)
      {
          SelectionSet acSSet = acSSPrompt.Value;

          // Step through the objects in the selection set
          foreach (SelectedObject acSSObj in acSSet)
          {
              // Check to make sure a valid SelectedObject object was returned
              if (acSSObj != null)
              {
                  // Open the selected object for write
                  Entity acEnt = acTrans.GetObject(acSSObj.ObjectId,
                                                   OpenMode.ForWrite) as Entity;

                  if (acEnt != null)
                  {
                      // Change the object's color to Green
                      acEnt.ColorIndex = 3;
                  }
              }
          }

          // Save the new object to the database
          acTrans.Commit();
      }

      // Dispose of the transaction
  }
}

Answer 2

可以使用其他 Autocad .NET 库（而不是 Interop 库）。但幸运的是，两者并不排斥。

您将需要引用包含以下命名空间的库：

using Autodesk.Autocad.ApplicationServices
using Autodesk.Autocad.EditorInput
using Autodesk.Autocad.DatabaseServices

（您可以从 Autodesk 免费下载 Object Arx 库）：

您需要从 autocad

Editor

访问

Document

。 根据您显示的代码，您可能正在使用

AcadDocument

文档。 因此，要将

AcadDocument

转换为

Document

，请执行以下操作：

//These are extension methods and must be in a static class
//Will only work if Doc is saved at least once (has full name) - if document is new, the name will be 
public static Document GetAsAppServicesDoc(this IAcadDocument Doc)
    {
        return Application.DocumentManager.OfType<Document>().First(D => D.Name == Doc.FullOrNewName());
    }

---

 public static string FullOrNewName(this IAcadDocument Doc)
    {
        if (Doc.FullName == "")
            return Doc.Name;
        else
            return Doc.FullName;
    }

---

一旦您获得了

Document

，请获得

Editor

，然后获得

GetSelection(Options, Filter)

选项包含属性

SingleOnly

和

SinglePickInSpace

。将其设置为

true

即可满足您的要求。 （两个都试试看哪个效果更好）

//Seleciton options, with single selection
PromptSelectionOptions Options = new PromptSelectionOptions();
Options.SingleOnly = true;
Options.SinglePickInSpace = true;

//This is the filter for blockreferences
SelectionFilter Filter = new SelectionFilter(new TypedValue[] { new TypedValue(0, "INSERT") });


//calls the user selection
PromptSelectionResult Selection = Document.Editor.GetSelection(Options, Filter);

if (Selection.Status == PromptStatus.OK)
{
    using (Transaction Trans = Document.Database.TransactionManager.StartTransaction())
    {
        //This line returns the selected items
       AcadBlockReference SelectedRef = (AcadBlockReference)(Trans.GetObject(Selection.Value.OfType<SelectedObject>().First().ObjectId, OpenMode.ForRead).AcadObject);
    }
}

Answer 3

选择一个实体的更好方法是使用 GetEntity 方法而不是 GetSelection。使用示例可以是：

/// <summary> Prompt the user to select one object. </summary>
/// <param name="promptMessage"> Message to display before prompting the user. </param>
/// <returns> ObjectId of the selected object, ObjectId.Null if selection fails. </returns>
internal static ObjectId SelectObject(string promptMessage = "")
{
  AcDoc acDoc = AcAp.DocumentManager.MdiActiveDocument;

  // Prepare objectId for returning
  ObjectId selection;

  // Prepare prompt options
  PromptEntityOptions options = new PromptEntityOptions(promptMessage)
  {
    AllowNone = false, // Do not allow empty result
  };

  // Get the selection result
  PromptEntityResult result = acDoc.Editor.GetEntity(options);

  // If selection went OK, save the result, otherwise ObjectId.Null
  if (result.Status == PromptStatus.OK)
  {
    selection = result.ObjectId;
  }
  else
  {
    acDoc.Editor.WriteMessage("\n Selection failure.");
    selection = ObjectId.Null;
  }

  // Return the selected objectId
  return selection;
}