DragDrop registration did not succeed.

Add-in Express™ Support Service
That's what is more important than anything else

DragDrop registration did not succeed.
This issue is raise while we used Add-In Express 9.2.4635 but worked fine with 9.1.xxxx version 
Davinder Kumar

Posts: 2
Joined: 2018-12-11

I am using Add-In Express 9.2.4635 standard version. We are facing issue on Windows 7 (32Bits/64Bits) with Office 365 ProPlus (32Bits/64Bits). Following are observations due to that we guess it's only issue with Add-In Express 9.2.xxxx version.

1. Outlook plugin worked fine on same configuration when we used 9.1.xxxx version of Add-In Express.
2. When we use 9.2.xxxx version, it's worked fine on Windows 10 (64 Bits) with Office ProPlus (64 Bits).

Following is the error we faced:

System.InvalidOperationException: DragDrop registration did not succeed. ---> System.Threading.ThreadStateException: Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it.
at System.Windows.Forms.Control.SetAcceptDrops(Boolean accept)
--- End of inner exception stack trace ---
at System.Windows.Forms.Control.SetAcceptDrops(Boolean accept)
at System.Windows.Forms.Control.OnHandleCreated(EventArgs e)
at System.Windows.Forms.TreeView.OnHandleCreated(EventArgs e)
at TeamConnectOutlookAddIn.ProjectTree.OnHandleCreated(EventArgs e)
at System.Windows.Forms.Control.WmCreate(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.TreeView.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

We already tried the solution related to STA mention on your forums and on other forums but we are facing same issue on Windows 7 configuration.
Posted 14 May, 2019 00:37:26 Top
Andrei Smolin

Add-in Express team

Posts: 16843
Joined: 2006-05-11
Hello Davinder,

Is it possible that you create that form in a thread other than the main one? If not, would it be possible for us to get a sample project reproducing the issue? You can send it to the support email address; find it in {Add-in Express installation folder}\readme.txt; please make sure your email contains a link to this topic.

Regards from Belarus (GMT+3),

Andrei Smolin
Add-in Express Team Leader
Posted 14 May, 2019 08:55:10 Top