How to drag files from c# winforms app to outlook message -

I am trying to drag one or more files from Outlook mail-messages from my application. If I drag on my desktop the file is copied as expected in the form of a desktop, but when a new approach is dragged into the 2013 mail message, nothing happens ... only when I click the 'Attachment Textbox' Clearly pull it out, it does not appear as useful because the attachment-textbox is not shown by default

I do not understand that when I Drag the files by dragging from the desktop, I can skip them and the attachment-text automatically shows to show the files, but when I pull it from my app then it is not working ..., my code is: / P>

  Private Zero Form 1_MouseDown (Object Sender, MouseEventArgs E) {var _files = new string [] {@ "E: \ Temp \ OR_rtftemplates.xml", @ "E: \ Temp \ Tail Web_Trace.cmd "}; Var fileDragDAdata = new data object (data format.filedrop, _file); (Sender as form). Dodradrope (file dragadata, dragfifacts, all); Console.print line ("{0} - button 1_MouseDown", date time.Now timeoffs); } I have added the files to the databackback using the 'SetFileDropList' method but it does not make any difference.  
 There should be some magic property, I have to do the right thing with the view to see it.  
 I hope someone can put some light on it.  
 Thank you, Jürgen. I just tested a few other things on the machine running the .NET 4.0 (the application was compiled in .NET 4.5). This works after I / O  
 
 
, change the NET target for 4.0 and recompiling, files A new approach might be very strange by dragging it into a message, which may later be a problem migrating to .NET 4.5 ... but now it works ...