Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.EditorInput
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.ApplicationServices
Public Class class1
    Friend Shared Sub CreateMyBlock()
        Dim db As Database = Application.DocumentManager.MdiActiveDocument.Database
        Using tr As Transaction = db.TransactionManager.StartTransaction()
            Dim bt As BlockTable = TryCast(tr.GetObject(db.BlockTableId, OpenMode.ForRead), BlockTable)
            If bt.Has("MyBlock") = False Then
                bt.UpgradeOpen()
                Dim btr As New BlockTableRecord()
                btr.Name = "MyBlock"
                btr.Origin = Point3d.Origin
                bt.Add(btr)
                tr.AddNewlyCreatedDBObject(btr, True)
                ' Attribute Definition
                Dim attdef As New AttributeDefinition(Point3d.Origin, "MilliSeconds\PSeconds\PMinutes", "Time", "Time ?", db.Textstyle)
                attdef.IsMTextAttributeDefinition = True
                btr.AppendEntity(attdef)
                tr.AddNewlyCreatedDBObject(attdef, True)
            End If
            tr.Commit()
        End Using
    End Sub

    Friend Shared Sub CreateMyBlockRef()
        Dim doc As Document = Application.DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database
        Dim ed As Editor = doc.Editor
        Dim ppo As New PromptPointOptions(vbLf & "Specify insertion point :")
        Dim ppr As PromptPointResult = ed.GetPoint(ppo)
        If ppr.Status <> PromptStatus.OK Then
            Return
        End If
        Dim insertionPoint As Point3d = ppr.Value
        Using tr As Transaction = db.TransactionManager.StartTransaction()
            Dim bt As BlockTable = TryCast(db.BlockTableId.GetObject(OpenMode.ForRead), BlockTable)
            Dim blockDef As BlockTableRecord = TryCast(bt("MyBlock").GetObject(OpenMode.ForRead), BlockTableRecord)
            Dim ms As BlockTableRecord = TryCast(bt(BlockTableRecord.ModelSpace).GetObject(OpenMode.ForWrite), BlockTableRecord)
            Dim blockRef As New BlockReference(insertionPoint, blockDef.ObjectId)
            ms.AppendEntity(blockRef)
            tr.AddNewlyCreatedDBObject(blockRef, True)
            For Each id As ObjectId In blockDef
                Dim obj As DBObject = id.GetObject(OpenMode.ForRead)
                Dim attDef As AttributeDefinition = TryCast(obj, AttributeDefinition)
                If (attDef IsNot Nothing) AndAlso (Not attDef.Constant) Then
                    Dim attRef As New AttributeReference()
                    attRef.SetAttributeFromBlock(attDef, blockRef.BlockTransform)
                    attRef.TextString = [String].Format("MilliSeconds : {0}\PSeconds : {1}\PMinutes : {2}",DateTime.Now.Millisecond.ToString(), DateTime.Now.Second.ToString(), DateTime.Now.Minute.ToString())
                    blockRef.AttributeCollection.AppendAttribute(attRef)
                    tr.AddNewlyCreatedDBObject(attRef, True)
                End If
            Next
            tr.Commit()
        End Using
    End Sub

    <CommandMethod("Test")> _
    Public Shared Sub TestMethod()
        CreateMyBlock()
        CreateMyBlockRef()
    End Sub
End Class