topic Re: Get an already open active Excel workbook in AutoCad 2025 in .NET Forum

Get an already open active Excel workbook in AutoCad 2025

Thomas.Oppen — Tue, 18 Feb 2025 13:00:26 GMT

One of my .net plugins reads and writes data to an aleady open active Excel workbook.

To get the Excel sheet I'm using

Dim appXL As Excel.Application Dim wbXL As Excel.Workbook Dim shXL As Excel.Worksheet appXL = GetObject(, "Excel.Application") wbXL = appXL.ActiveWorkbook shXL = appXL.ActiveSheet

This has been working perfectly in AutoCad 2022 and 2023.

In AutoCAD 2025 GetObject(, "Excel.Application") doesn't deliver the application objetct anymore ...

Up to now I rcognized that this might be related to AutoCad 2025 using .net 8.

I have tried

- GetObject("", "Excel.Application")

- Marshal.GetActiveObject("Excel.Application")

- DirectCast(Marshal.GetActiveObject("Excel.Application"), Excel.Application)

But to no avail ... all three are working in AutoCad 2023 but not in 2025.

Do you have any ideas for approaches on this?

Best regards

Thomas

Re: Get an already open active Excel workbook in AutoCad 2025

_gile — Tue, 02 Dec 2025 12:58:46 GMT

Hi,

You should read this topic (updated link).

Re: Get an already open active Excel workbook in AutoCad 2025

Thomas.Oppen — Wed, 19 Feb 2025 06:18:33 GMT

Thanks a lot _gile!

Shame on me, but I don't really understand the code - but I think I understand what it is doing and it is working fine.

Here is the code in Visual Basic:

<DllImport("ole32")> Private Shared Function CLSIDFromProgIDEx(<MarshalAs(UnmanagedType.LPWStr)> ByVal lpszProgID As String, <Out> ByRef lpclsid As Guid) As Integer End Function <DllImport("oleaut32")> Private Shared Function GetActiveObject(<MarshalAs(UnmanagedType.LPStruct)> ByVal rclsid As Guid, ByVal pvReserved As IntPtr, <Out> <MarshalAs(UnmanagedType.IUnknown)> ByRef ppunk As Object) As Integer End Function Public Shared Function GetActiveObject(ByVal progId As String, ByVal Optional throwOnError As Boolean = False) As Object If progId Is Nothing Then Throw New ArgumentNullException(NameOf(progId)) Dim clsid = Nothing Dim hr = CLSIDFromProgIDEx(progId, clsid) If hr < 0 Then If throwOnError Then Marshal.ThrowExceptionForHR(hr) Return Nothing End If Dim obj As Object = Nothing hr = GetActiveObject(clsid, IntPtr.Zero, obj) If hr < 0 Then If throwOnError Then Marshal.ThrowExceptionForHR(hr) Return Nothing End If Return obj End Function

Re: Get an already open active Excel workbook in AutoCad 2025

alaammehrem — Wed, 01 Oct 2025 11:06:04 GMT

Hi, I’m having the same problem with 2025, and the Typepad link doesn’t open. Could I get another reference to the solution?

My issue is that I cannot use any external library like OpenXML, ClosedXML, or EPPlus to read and write Excel files, even though they worked normally in earlier versions.

Many thanks.

Re: Get an already open active Excel workbook in AutoCad 2025

duykhaone — Tue, 02 Dec 2025 12:17:56 GMT

The topic was deteted 😞

Re: Get an already open active Excel workbook in AutoCad 2025

duykhaone — Tue, 02 Dec 2025 12:20:30 GMT

The topic was deleted, can you show me the code 😞

Re: Get an already open active Excel workbook in AutoCad 2025

_gile — Tue, 02 Dec 2025 13:05:23 GMT

Hi,

I updated the link in reply #2

Here's the code:

[DllImport("ole32")] private static extern int CLSIDFromProgIDEx( [MarshalAs(UnmanagedType.LPWStr)] string lpszProgID, out Guid lpclsid); [DllImport("oleaut32")] private static extern int GetActiveObject( [MarshalAs(UnmanagedType.LPStruct)] Guid rclsid, IntPtr pvReserved, [MarshalAs(UnmanagedType.IUnknown)] out object ppunk); public static object? GetActiveObject(string progId, bool throwOnError = false) { if (progId == null) throw new ArgumentNullException(nameof(progId)); var hr = CLSIDFromProgIDEx(progId, out var clsid); if (hr < 0) { if (throwOnError) Marshal.ThrowExceptionForHR(hr); return null; } hr = GetActiveObject(clsid, IntPtr.Zero, out var obj); if (hr < 0) { if (throwOnError) Marshal.ThrowExceptionForHR(hr); return null; } return obj; }