Help on LINQ query to list all block references in current drawing.

[ProfWolfMan]

Dear All,

Why my LINQ query always returns nothing ?

There is already some block refernces in the current drawing.

Please advise me where i am worng?

 <CommandMethod("BlockList")> _
    Public Sub BlockList()

        '' Get the current document and database
        Dim acDoc As Object = Application.DocumentManager.MdiActiveDocument
        Dim acCurDb As Object = HostApplicationServices.WorkingDatabase

        Dim acCurBlkTbl As Object = acCurDb.BlockTableId

        Dim blkrefs = From b In CType(CTypeDynamic(acCurBlkTbl, GetType(IEnumerable(Of Object))),  _
                              IEnumerable(Of Object))
                          Where (b.GetRXClass().Name = "AcDbBlockReference")
                          Select b

        For Each blk As BlockReference In blkrefs
            acDoc.Editor.WriteMessage(vbCrLf + blk.Name + vbCrLf)
        Next

    End Sub

FYI : There are many goodways to list all block references. But here i am trying to study Dynamic and LINQ features of .NET.

[_gile · Accepted solution]

Hi,

The BlockTable contains BlockTableRecordS, not BlockReferenceS.

[ProfWolfMan]

Hi Gilles,

Thanks for point out the Error.

Below is corrected one.

    <CommandMethod("BlockList")> _
    Public Sub BlockList()

        '' Get the current document and database
        Dim acDoc As Object = Application.DocumentManager.MdiActiveDocument
        Dim acCurDb As Object = HostApplicationServices.WorkingDatabase

        Dim acCurSpace = acCurDb.CurrentSpaceId

        Dim blkrefs = From b In CType(CTypeDynamic(acCurSpace, GetType(IEnumerable(Of Object))),  _
                            IEnumerable(Of Object))
                            Where (b.GetRXClass().Name = "AcDbBlockReference")
                            Select b

        For Each blk As Object In blkrefs
            acDoc.Editor.WriteMessage(vbCrLf + blk.Name + vbCrLf)
        Next

    End Sub