Extracting XML data from drawings using a new .NET API in AutoCAD 2009

This post is the latest in the series of closer looks at the new APIs in AutoCAD 2009. It covers the Data Extraction API, a new .NET API allowing you to drive the Data Extraction feature inside AutoCAD.

There is a very thorough C# sample included on the ObjectARX SDK (under samples/dotNet/DataExtraction), so I thought I'd focus on a much simpler example where we extract data from a single drawing.

Here's the C# code:

using System.Collections.Generic;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.DataExtraction;

namespace DataExtraction

{

  public class Commands

  {

    const string path =

      @"c:\Program Files\Autodesk\AutoCAD 2009\Sample\";

    const string fileName =

      "Visualization - Aerial.dwg";

    const string outputXmlFile =

      @"c:\temp\data-extract.xml";

    [CommandMethod("extd")]

    public void extractData()

    {

      if (!System.IO.File.Exists(path + fileName))

      {

        Document doc =

          Application.DocumentManager.MdiActiveDocument;

        Editor ed =

          doc.Editor;

        ed.WriteMessage("\nFile does not exist.");

        return;

      }

      // Create some settings for the extraction

      IDxExtractionSettings es =

        new DxExtractionSettings();

      IDxDrawingDataExtractor de =

        es.DrawingDataExtractor;

      de.Settings.ExtractFlags =

        ExtractFlags.ModelSpaceOnly |

        ExtractFlags.XrefDependent |

        ExtractFlags.Nested;

      // Add a single file to the settings

      IDxFileReference fr =

        new DxFileReference(path, path + fileName);

      de.Settings.DrawingList.AddFile(fr);

      // Scan the drawing for object types & their properties

      de.DiscoverTypesAndProperties(path);

      List<IDxTypeDescriptor> types =

        de.DiscoveredTypesAndProperties;

      // Select all the types and properties for extraction

      // by adding them one-by-one to these two lists

      List<string> selTypes = new List<string>();

      List<string> selProps = new List<string>();

      foreach (IDxTypeDescriptor type in types)

      {

        selTypes.Add(type.GlobalName);

        foreach (

          IDxPropertyDescriptor pr in type.Properties

        )

        {

          if (!selProps.Contains(pr.GlobalName))

            selProps.Add(pr.GlobalName);

        }

      }

      // Pass this information to the extractor

      de.Settings.SetSelectedTypesAndProperties(

        types,

        selTypes,

        selProps

      );

      // Now perform the extraction itself

      de.ExtractData(path);

      // Get the results of the extraction

      System.Data.DataTable dataTable =

        de.ExtractedData;

      // Output the extracted data to an XML file

      if (dataTable.Rows.Count > 0)

      {

        dataTable.TableName = "My_Data_Extract";

        dataTable.WriteXml(outputXmlFile);

      }

    }

  }

}

Here are the first few objects from the output file found in c:\temp\data-extract.xml after running the EXTD command:

<?xml version="1.0" standalone="yes"?>

<DocumentElement>

  <My_Data_Extract>

    <AcDxHandleData>183</AcDxHandleData>

    <Layer>0</Layer>

    <LinetypeScale>1</LinetypeScale>

    <PlotStyleName>ByLayer</PlotStyleName>

    <LineWeight>ByLayer</LineWeight>

    <Material>Material 3</Material>

    <Linetype>ByLayer</Linetype>

    <Color>ByLayer</Color>

    <AcDxObjectTypeName>3D Solid</AcDxObjectTypeName>

    <AcDxObjectTypeGlobalName>

      Autodesk.AutoCAD.DatabaseServices.Solid3d

    </AcDxObjectTypeGlobalName>

    <AcDxDwgSummaryDwgName>

      Visualization - Aerial.dwg

    </AcDxDwgSummaryDwgName>

    <AcDxDwgSummaryDwgLocation>

      c:\Program Files\Autodesk\AutoCAD 2009\Sample

    </AcDxDwgSummaryDwgLocation>

    <AcDxDwgSummaryDwgSize>472480</AcDxDwgSummaryDwgSize>

    <AcDxDwgSummaryDwgCreated>

      2007-01-03T00:44:20+01:00

    </AcDxDwgSummaryDwgCreated>

    <AcDxDwgSummaryDwgModified>

      2007-01-03T00:44:20+01:00

    </AcDxDwgSummaryDwgModified>

    <AcDxDwgSummaryDwgAccessed>

      2008-03-03T11:40:53.796875+01:00

    </AcDxDwgSummaryDwgAccessed>

    <AcDxDwgSummaryDwgTitle />

    <AcDxDwgSummaryDwgSubject />

    <AcDxDwgSummaryDwgAuthor />

    <AcDxDwgSummaryDwgKeywords />

    <AcDxDwgSummaryDwgComments />

    <AcDxDwgSummaryDwgHyperLinkBase />

    <AcDxDwgSummaryDwgLastSavedBy>

      thompsl

    </AcDxDwgSummaryDwgLastSavedBy>

    <AcDxDwgSummaryDwgRevisionNumber />

    <AcDxDwgSummaryDwgTotalEditingTime>

      1179

    </AcDxDwgSummaryDwgTotalEditingTime>

    <AcDxEntityHyperlink />

  </My_Data_Extract>

  <My_Data_Extract>

    <AcDxHandleData>191</AcDxHandleData>

    <Layer>0</Layer>

    <LinetypeScale>1</LinetypeScale>

    <PlotStyleName>ByLayer</PlotStyleName>

    <LineWeight>ByLayer</LineWeight>

    <Material>Material 3</Material>

    <Linetype>ByLayer</Linetype>

    <Color>ByLayer</Color>

    <AcDxObjectTypeName>3D Solid</AcDxObjectTypeName>

    <AcDxObjectTypeGlobalName>

      Autodesk.AutoCAD.DatabaseServices.Solid3d

    </AcDxObjectTypeGlobalName>

    <AcDxDwgSummaryDwgName>

      Visualization - Aerial.dwg

    </AcDxDwgSummaryDwgName>

    <AcDxDwgSummaryDwgLocation>

      c:\Program Files\Autodesk\AutoCAD 2009\Sample

    </AcDxDwgSummaryDwgLocation>

    <AcDxDwgSummaryDwgSize>472480</AcDxDwgSummaryDwgSize>

    <AcDxDwgSummaryDwgCreated>

      2007-01-03T00:44:20+01:00

    </AcDxDwgSummaryDwgCreated>

    <AcDxDwgSummaryDwgModified>

      2007-01-03T00:44:20+01:00

    </AcDxDwgSummaryDwgModified>

    <AcDxDwgSummaryDwgAccessed>

      2008-03-03T11:40:53.796875+01:00

    </AcDxDwgSummaryDwgAccessed>

    <AcDxDwgSummaryDwgTitle />

    <AcDxDwgSummaryDwgSubject />

    <AcDxDwgSummaryDwgAuthor />

    <AcDxDwgSummaryDwgKeywords />

    <AcDxDwgSummaryDwgComments />

    <AcDxDwgSummaryDwgHyperLinkBase />

    <AcDxDwgSummaryDwgLastSavedBy>

      thompsl

    </AcDxDwgSummaryDwgLastSavedBy>

    <AcDxDwgSummaryDwgRevisionNumber />

    <AcDxDwgSummaryDwgTotalEditingTime>

      1179

    </AcDxDwgSummaryDwgTotalEditingTime>

    <AcDxEntityHyperlink />

  </My_Data_Extract>

  <!-- Stuff deleted from the XML output -->

  <!-- ... -->

</DocumentElement>

Comments

[Fernando Malard]

Kean,
Is this available through C++?
How to make our custom objects support XML exporting?

Fernando.

[Kean]

Fernando,

I don't think that's currently possible: it doesn't appear to pick up properties exposed through COM, although I haven't tried with a managed wrapper.

Please submit your question via the ADN site for someone to look into.

Regards,

Kean

[Kean]

Oh - and this is a managed API, so it can be called from C++. There isn't an unmanaged C++ API, though.

Kean

[Tom]

When compiling, I get the following message: The type or namespace name 'DataExtraction' does not exist in the namespace 'Autodesk.AutoCAD' (are you missing an assembly reference?)

Which assembly do I need to add as a reference?

[Kean]

Ah yes - I missed a step: you need to add a project reference to AcDx.dll, which can be found in the inc-win32 and inc-x64 folders of the ObjectARX 2009 SDK (as well as being in the AutoCAD 2009 root folder).

Regards,

Kean

[Tom]

Hello,

Was the following an error:
IDxExtractionSettings es =
es = new DxExtractionSettings();

Should it have been written like:
IDxExtractionSettings es = new DxExtractionSettings();

Or, doesn't it make any difference?

Thank You

[Kean]

Hi Tom,

It was a typo - thanks for spotting it. I've fixed the post.

Regards,

Kean

[wesley]

you can filter the properties customized and bring only what you need?

[Kean]

I believe so, although I didn't try it.

Kean

[David Osborne]

Hi Kean.
I just popped this into VB and took out the hard coded filenames. I ran it on a drawing created by my automation program, and the only thing I don't see extracted is Xdata.
I'd be interested in figuring out if that could be done. (in the data extraction tool, I know how to do it otherwise)

Actually I also saw something else a little strange... I have a particular type of block which is inserted with varying X-scales so that the length of the block changes. The Attribute references show up under the data for the block, but the specific data for the attribute references themselves does not show up next in the list, like it did for other uniformly scaled blocks. At the moment I don't think this concerns me, I just found it interesting.

[Kean]

Hi David,

I hadn't tried this with Xdata, but it doesn't fully surprise me that this isn't currently supported.

Xdata content tends to be stored fairly generically - the group codes don't have standardised, human-readable labels - so some logic would be needed to map these to XML elements. Not to say it's very hard to do, but it doesn't surprise me that it hasn't been done.

I hadn't come across non-uniform blocks acting differently. If you're an ADN member it would be great if you could submit it there with a reproducible case.

Thanks,

Kean