Showing AutoCAD's hatch dialog from a .NET application

This question was posted by csharpbird:

How to get the Hatch dialog using .NET? It seems that there is no such class in the .NET API?

It's true there is no public class - or even a published function - to show the hatch dialog inside AutoCAD. It is, however, possible to P/Invoke an unpublished (and therefore unsupported and liable to change without warning) function exported from acad.exe.

Here's some C# code that shows how. The code works for AutoCAD 2007, but will be different for AutoCAD 2006: the function takes and outputs strings, so the change to Unicode in 2007 will have modified the function signature.

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.ApplicationServices;

using System.Reflection;

using System.Runtime.InteropServices;

namespace HatchDialogTest

{

  public class Commands

  {

    [DllImport(

        "acad.exe",

        EntryPoint =

          "?acedHatchPalletteDialog@@YA_NPB_W_NAAPA_W@Z",

        CharSet = CharSet.Auto

      )

    ]

    static extern bool acedHatchPalletteDialog(

      string currentPattern,

      bool showcustom,

      out string newpattern

    );

    [CommandMethod("SHD")]

    static public void ShowHatchDialog()

    {

      string sHatchType;

      string sNewHatchType;

      bool bRet;

      sHatchType = "ANGLE";

      bRet =

        acedHatchPalletteDialog(

          sHatchType,

          true,

          out sNewHatchType

        );

      if (bRet)

      {

        Editor ed =

          Application.DocumentManager.MdiActiveDocument.Editor;

        ed.WriteMessage(

          "\nHatch type selected: " + sNewHatchType

        );

      }

    }

  }

}

Here's what happens when you run the code:

Command: SHD

Hatch type selected: SWAMP

Update

Someone asked me for the VB.NET code for this one (it was quite tricky to marshall the new string being returned). As I'd put it together, I thought I'd post it here:

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.EditorInput

Imports System.Text

Namespace HatchDialogTest

  Public Class Commands

    Private Declare Auto Function acedHatchPalletteDialog _

    Lib "acad.exe" _

    Alias "?acedHatchPalletteDialog@@YA_NPB_W_NAAPA_W@Z" _

    (ByVal currentPattern As String, _

    ByVal showcustom As Boolean, _

    ByRef newpattern As StringBuilder) As Boolean

    <CommandMethod("SHD")> _

    Public Sub ShowHatchDialog()

      Dim sHatchType As String = "ANGLE"

      Dim sNewHatchType As New StringBuilder

      Dim bRet As Boolean = _

        acedHatchPalletteDialog(sHatchType, _

          True, sNewHatchType)

      If bRet And sNewHatchType.ToString.Length > 0 Then

        Dim ed As Editor

        ed = _

          Application.DocumentManager.MdiActiveDocument.Editor

        ed.WriteMessage( _

          vbLf + "Hatch type selected: " + _

          sNewHatchType.ToString)

      End If

    End Sub

  End Class

End Namespace

Comments

[Fatty]

Dear Kean
Thanks again for an example
it worked like a charm
Here is VB.NET version I used

[Code deleted by Kean at the request of Fatty]

[Fatty]

Oops...
the code uploaded incorrectly
remove it please

Oleg

[Limin]

Kean,

Is there .Net interface for autocad command "DrawOrder"? For example: after solid-hatch a polyline, need to reorder polyline and hatch, how to make it happen using .NET? Thanks!

[Kean]

Limin,

The short answer is that it should be possible, using Autodesk.AutoCAD.DatabaseServices.DrawOrderTable.

When I have some time I'll take a look into creating some sample code. In this case do you want to put the hatch behind the boundary? They don't typically intersect, so that change won't be very visible... unless you mean they need to be reordered relative to other entities.

[Limin]

Kean, thanks for the quick response.

Actually it's not only pline boundary. I have some furniture inside that polyline. So after running the hatch, I want them behind hatch. When you start working on draworder example, can you also include some code add xdata? I have tried hatch.XData.add(ResultBuffer), it always retruns error like following:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object.

Have a great trip to China. I have some good friends in Beijing, if you need some help, please let me know.

[Kean]

I've created a new post on this:

http://through-the-interface.typepad.com/through_the_interface/2007/03/manipulating_th.html

Regarding the XData issue... it's not specifically relevant to the topic, so I've left it off. There are two likely reasons for your error: either the Registered Appication has not been added properly, or the list of typed values you're passing in via the ResultBuffer is malformed, in some way.

Thanks for your kind offer, by the way. My Autodesk colleagues in Beijing have been incredibly welcoming and helpful, but I'll certainly let you know if I need additional help.

[Andrey]

This example doesn't work on Autocad 2009. Can I use this method to show hatch dialog with Autocad 2009 and vb.net 2008?

[Kean Walmsley]

It worked fine for me with AutoCAD 2009.

Kean

[Adam Davis]

Hi Kean,

I have been attempting to follow the same path for showing the text style dialog. I can get the Dialog to show but it doesn't initialise properly. Any pointers gratefully received.

Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.Runtime

Namespace TextStyleDialogTest

Public Class Commands
Private Declare Auto Sub acedTextStyleDialog2006 Lib "acad.exe" Alias "?invokeTextStyleDialog@@YAXPAVAcDbDatabase@@PAV?$CStringT@DV?$StrTraitMFC@DV?$ChTraitsCRT@D@ATL@@@@@ATL@@@Z" (ByVal AcadDatabase As IntPtr, ByVal StyleName As String)
Private Declare Auto Sub acedTextStyleDialog2007 Lib "acad.exe" Alias "?invokeTextStyleDialog@@YAXPAVAcDbDatabase@@PAV?$CStringT@_WV?$StrTraitMFC_DLL@_WV?$ChTraitsCRT@_W@ATL@@@@@ATL@@@Z" (ByVal AcadDatabase As IntPtr, ByVal StyleName As String)

Public Sub ShowTextStyleDialog()
Dim db As Autodesk.AutoCAD.DatabaseServices.Database
db = Application.DocumentManager.MdiActiveDocument.Database
If Autodesk.AutoCAD.ApplicationServices.Application.Version.Major > 16 Then
acedTextStyleDialog2007(db.UnmanagedObject, "Standard")
Else
acedTextStyleDialog2006(db.UnmanagedObject, "Standard")
End If

End Sub

End Class

End Namespace

Thanks

Adam

[Kean Walmsley]

Hi Adam,

Sorry - nothing immediately obvious springs to mind.

I suggest posting your question via ADN, if you're a member, of otherwise the AutoCAD .NET Discussion Group.

Regards,

Kean

[Adam Davis]

Hi Kean,

Thanks for the speedy reply.

I tried ADN and was given pointers to either Send command or recreating the dialog in .NET.
Fine, but as was so near with InvokeTextStyleDialog and you obviously have coerced AutoCAD with other dialogs I thought I would post just in case it was something obvious :-)

I will try the .NET forums.

Thanks

Adam

[Kean Walmsley]

Hi Adam,

OK, I just unmangled the name using DependencyWalker, and see the signature is more complex than you thought:

void invokeTextStyleDialog(class AcDbDatabase *,class ATL::CStringT<wchar_t,class StrTraitMFC_DLL<wchar_t,class ATL::ChTraitsCRT<wchar_t> > > *)

I think the chances of calling this unpublished function via P/Invoke are slim to none, I'm afraid. And much closer to none than slim, speaking frankly. At least it's not something I'd attempt, personally.

Regards,

Kean

[Adam Davis]

Hi Kean,

No problem - I thought I was close but obviously not :-)
Still I learnt today that you can Undecorate a name in Dependency Walker which makes it all worthwhile.

Thanks again,

Adam