提取属性信息 （.NET）

您可以使用该属性从块引用中提取属性信息。该属性返回附加到块的属性引用的集合。单步执行集合时，可以使用该属性查看是否可以更改属性值。AttributeCollectionAttributeCollectionIsConstant

您不需要模板文件来提取属性信息，也不会创建任何属性信息文件。只需循环访问属性引用的集合，使用属性引用的 和 属性来检查属性信息。您还需要检查 is 或 ，如果为 True，则需要获取具有该属性的多行属性的文本值。TagTextStringIsMTextAttributeTrueFalseMTextAttribute

有关提取属性信息的更多信息，请参阅产品帮助系统中的“关于从块属性中提取数据”。

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry

<CommandMethod("GettingAttributes")> _
Public Sub GettingAttributes()
    ' Get the current database and start a transaction
    Dim acCurDb As Autodesk.AutoCAD.DatabaseServices.Database
    acCurDb = Application.DocumentManager.MdiActiveDocument.Database

    Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
        ' Open the Block table for read
        Dim acBlkTbl As BlockTable
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead)

        Dim blkRecId As ObjectId = ObjectId.Null

        If Not acBlkTbl.Has("TESTBLOCK") Then
            Using acBlkTblRec As New BlockTableRecord
                acBlkTblRec.Name = "TESTBLOCK"

                ' Set the insertion point for the block
                acBlkTblRec.Origin = New Point3d(0, 0, 0)

                ' Add an attribute definition to the block
                Using acAttDef As New AttributeDefinition
                    acAttDef.Position = New Point3d(5, 5, 0)
                    acAttDef.Prompt = "Attribute Prompt"
                    acAttDef.Tag = "AttributeTag"
                    acAttDef.TextString = "Attribute Value"
                    acAttDef.Height = 1
                    acAttDef.Justify = AttachmentPoint.MiddleCenter
                    acBlkTblRec.AppendEntity(acAttDef)

                    acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForWrite)
                    acBlkTbl.Add(acBlkTblRec)
                    acTrans.AddNewlyCreatedDBObject(acBlkTblRec, True)
                End Using

                blkRecId = acBlkTblRec.Id
            End Using
        Else
            blkRecId = acBlkTbl("TESTBLOCK")
        End If

        ' Create and insert the new block reference
        If blkRecId <> ObjectId.Null Then
            Dim acBlkTblRec As BlockTableRecord
            acBlkTblRec = acTrans.GetObject(blkRecId, OpenMode.ForRead)

            Using acBlkRef As New BlockReference(New Point3d(5, 5, 0), acBlkTblRec.Id)

                Dim acCurSpaceBlkTblRec As BlockTableRecord
                acCurSpaceBlkTblRec = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite)

                acCurSpaceBlkTblRec.AppendEntity(acBlkRef)
                acTrans.AddNewlyCreatedDBObject(acBlkRef, True)

                ' Verify block table record has attribute definitions associated with it
                If acBlkTblRec.HasAttributeDefinitions Then
                    ' Add attributes from the block table record
                    For Each objID As ObjectId In acBlkTblRec

                        Dim dbObj As DBObject = acTrans.GetObject(objID, OpenMode.ForRead)

                        If TypeOf dbObj Is AttributeDefinition Then
                            Dim acAtt As AttributeDefinition = dbObj

                            If Not acAtt.Constant Then
                                Using acAttRef As New AttributeReference

                                    acAttRef.SetAttributeFromBlock(acAtt, acBlkRef.BlockTransform)
                                    acAttRef.Position = acAtt.Position.TransformBy(acBlkRef.BlockTransform)

                                    acAttRef.TextString = acAtt.TextString

                                    acBlkRef.AttributeCollection.AppendAttribute(acAttRef)
                                    acTrans.AddNewlyCreatedDBObject(acAttRef, True)
                                End Using
                            End If
                        End If
                    Next

                    ' Display the tags and values of the attached attributes
                    Dim strMessage As String = ""
                    Dim attCol As AttributeCollection = acBlkRef.AttributeCollection

                    For Each objID As ObjectId In attCol
                        Dim dbObj As DBObject = acTrans.GetObject(objID, OpenMode.ForRead)

                        Dim acAttRef As AttributeReference = dbObj

                        strMessage = strMessage & "Tag: " & acAttRef.Tag & vbCrLf & _
                                     "Value: " & acAttRef.TextString & vbCrLf

                        ' Change the value of the attribute
                        acAttRef.TextString = "NEW VALUE!"
                    Next

                    MsgBox("The attributes for blockReference " & acBlkRef.Name & " are: " & vbCrLf & strMessage)
                    strMessage = ""

                    For Each objID As ObjectId In attCol
                        Dim dbObj As DBObject = acTrans.GetObject(objID, OpenMode.ForRead)

                        Dim acAttRef As AttributeReference = dbObj

                        strMessage = strMessage & "Tag: " & acAttRef.Tag & vbCrLf & _
                                     "Value: " & acAttRef.TextString & vbCrLf
                    Next

                    MsgBox("The attributes for blockReference " & acBlkRef.Name & " are: " & vbCrLf & strMessage)
                End If
            End Using
        End If

        ' Save the new object to the database
        acTrans.Commit()

        ' Dispose of the transaction
    End Using
End Sub

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

[CommandMethod("GettingAttributes")]
public void GettingAttributes()
{
    // Get the current database and start a transaction
    Database acCurDb;
    acCurDb = Application.DocumentManager.MdiActiveDocument.Database;

    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Block table for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;

        ObjectId blkRecId = ObjectId.Null;

        if (!acBlkTbl.Has("TESTBLOCK"))
        {
            using (BlockTableRecord acBlkTblRec = new BlockTableRecord())
            {
                acBlkTblRec.Name = "TESTBLOCK";

                // Set the insertion point for the block
                acBlkTblRec.Origin = new Point3d(0, 0, 0);

                // Add an attribute definition to the block
                using (AttributeDefinition acAttDef = new AttributeDefinition())
                {
                    acAttDef.Position = new Point3d(5, 5, 0);
                    acAttDef.Prompt = "Attribute Prompt";
                    acAttDef.Tag = "AttributeTag";
                    acAttDef.TextString = "Attribute Value";
                    acAttDef.Height = 1;
                    acAttDef.Justify = AttachmentPoint.MiddleCenter;
                    acBlkTblRec.AppendEntity(acAttDef);

                    acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForWrite);
                    acBlkTbl.Add(acBlkTblRec);
                    acTrans.AddNewlyCreatedDBObject(acBlkTblRec, true);
                }

                blkRecId = acBlkTblRec.Id;
            }
        }
        else
        {
            blkRecId = acBlkTbl["CircleBlockWithAttributes"];
        }

        // Create and insert the new block reference
        if (blkRecId != ObjectId.Null)
        {
            BlockTableRecord acBlkTblRec;
            acBlkTblRec = acTrans.GetObject(blkRecId, OpenMode.ForRead) as BlockTableRecord;

            using (BlockReference acBlkRef = new BlockReference(new Point3d(5, 5, 0), acBlkTblRec.Id))
            {
                BlockTableRecord acCurSpaceBlkTblRec;
                acCurSpaceBlkTblRec = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;

                acCurSpaceBlkTblRec.AppendEntity(acBlkRef);
                acTrans.AddNewlyCreatedDBObject(acBlkRef, true);

                // Verify block table record has attribute definitions associated with it
                if (acBlkTblRec.HasAttributeDefinitions)
                {
                    // Add attributes from the block table record
                    foreach (ObjectId objID in acBlkTblRec)
                    {
                        DBObject dbObj = acTrans.GetObject(objID, OpenMode.ForRead) as DBObject;

                        if (dbObj is AttributeDefinition)
                        {
                            AttributeDefinition acAtt = dbObj as AttributeDefinition;

                            if (!acAtt.Constant)
                            {
                                using (AttributeReference acAttRef = new AttributeReference())
                                {
                                    acAttRef.SetAttributeFromBlock(acAtt, acBlkRef.BlockTransform);
                                    acAttRef.Position = acAtt.Position.TransformBy(acBlkRef.BlockTransform);

                                    acAttRef.TextString = acAtt.TextString;

                                    acBlkRef.AttributeCollection.AppendAttribute(acAttRef);
                                    acTrans.AddNewlyCreatedDBObject(acAttRef, true);
                                }
                            }
                        }
                    }

                    // Display the tags and values of the attached attributes
                    string strMessage = "";
                    AttributeCollection attCol = acBlkRef.AttributeCollection;

                    foreach (ObjectId objID in attCol)
                    {
                        DBObject dbObj = acTrans.GetObject(objID, OpenMode.ForRead) as DBObject;

                        AttributeReference acAttRef = dbObj as AttributeReference;

                        strMessage = strMessage + "Tag: " + acAttRef.Tag + "\n" +
                                        "Value: " + acAttRef.TextString + "\n";

                        // Change the value of the attribute
                        acAttRef.TextString = "NEW VALUE!";
                    }

                    Application.ShowAlertDialog("The attributes for blockReference " + acBlkRef.Name + " are:\n" + strMessage);

                    strMessage = "";
                    foreach (ObjectId objID in attCol)
                    {
                        DBObject dbObj = acTrans.GetObject(objID, OpenMode.ForRead) as DBObject;

                        AttributeReference acAttRef = dbObj as AttributeReference;

                        strMessage = strMessage + "Tag: " + acAttRef.Tag + "\n" +
                                        "Value: " + acAttRef.TextString + "\n";
                    }

                    Application.ShowAlertDialog("The attributes for blockReference " + acBlkRef.Name + " are:\n" + strMessage);
                }
            }
        }

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

        // Dispose of the transaction
    }
}

Sub GettingAttributes()
    ' Create the block
    Dim blockObj As AcadBlock
    Dim insertionPnt(0 To 2) As Double
    insertionPnt(0) = 0
    insertionPnt(1) = 0
    insertionPnt(2) = 0
    Set blockObj = ThisDrawing.Blocks.Add(insertionPnt, "TESTBLOCK")
 
    ' Define the attribute definition
    Dim attributeObj As AcadAttribute
    Dim height As Double
    Dim mode As Long
    Dim prompt As String
    Dim insertionPoint(0 To 2) As Double
    Dim tag As String
    Dim value As String
    height = 1
    prompt = "Attribute Prompt"
    insertionPoint(0) = 5
    insertionPoint(1) = 5
    insertionPoint(2) = 0
    tag = "AttributeTag"
    value = "Attribute Value"
 
    ' Create the attribute definition object on the block
    Set attributeObj = blockObj.AddAttribute(height, mode, prompt, insertionPoint, tag, value)
 
    ' Insert the block
    Dim blockRefObj As AcadBlockReference
    insertionPnt(0) = 2
    insertionPnt(1) = 2
    insertionPnt(2) = 0
    Set blockRefObj = ThisDrawing.ModelSpace.InsertBlock(insertionPnt, "TESTBLOCK", 1, 1, 1, 0)

    ' Get the attributes for the block reference
    Dim varAttributes As Variant
    varAttributes = blockRefObj.GetAttributes
 
    ' Move the attribute tags and values into a
    ' string to be displayed in a Msgbox
    Dim strAttributes As String
    strAttributes = ""
    Dim I As Integer
    For I = LBound(varAttributes) To UBound(varAttributes)
        strAttributes = strAttributes + "  Tag: " + _
        varAttributes(I).TagString + vbCrLf + _
        "   Value: " + varAttributes(I).textString
    Next

    MsgBox "The attributes for blockReference " + _
    blockRefObj.Name & " are: " & vbCrLf & strAttributes
 
    ' Change the value of the attribute
    ' Note: There is no SetAttributes. Once you have the
    ' variant array, you have the objects.
    ' Changing them changes the objects in the drawing.
    varAttributes(0).textString = "NEW VALUE!"
 
    ' Get the attributes again
    Dim newvarAttributes As Variant
    newvarAttributes = blockRefObj.GetAttributes
 
    ' Again, display the tags and values
    strAttributes = ""
    For I = LBound(varAttributes) To UBound(varAttributes)
        strAttributes = strAttributes + "  Tag: " + _
        newvarAttributes(I).TagString + vbCrLf + _
        "   Value: " + newvarAttributes(I).textString
    Next

    MsgBox "The attributes for blockReference " & _
    blockRefObj.Name & " are: " & vbCrLf & strAttributes
End Sub