Hier mal der Code:

Private Sub Button2_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Try
Dim con2 As SqlConnection
Dim cmd2 As SqlCommand
Dim Filename2 As String '= Integer.Parse(s.Remove(0, 3))
'Dim s As String = ""
Dim strQuery2 As String
Dim database2 As String
Dim get_servername2 As String
'get the value selected in Database Name dropdon menu/ combobox
database2 = cmbdatabase.Text
get_servername2 = cmbservername.Text.Trim 'get selected value of Server Name dropdown menu

Dim opendlg As New OpenFileDialog
Dim constr2 As String


'set SQL connection data source using default MASTER database --- 02.09.2019 con.ConnectionTimeout = 0 TM 03.09.2019 ==> conection Timeout=0
constr2 = "Data Source=" & get_servername2 & ";Initial Catalog=master; conection Timeout=0 ;Integrated Security=True" '& con.ConnectionTimeout = 0

'open SQL database to restore
If opendlg.ShowDialog = DialogResult.OK Then 'netframwork 4.5.x windows.forms.
Cursor = Cursors.WaitCursor
con2 = New SqlConnection(constr2) 'get/set connection data source
con2.Open() 'open connection

Dim dbCommmand As New SqlCommand(constr, con) ' 03.09.2019 ???????
dbCommmand.CommandTimeout = 6000 ' 03.09.2019 ?????? 1,6h

Filename2 = opendlg.FileName ' -= (Integer.Parse(s.Remove(0, 3))) geht nicht! - get the file name and path of the SQL database selected
strQuery2 = "Restore database " & database2 & " from disk='" & Filename2 & "'" '#### entfernen ! right(path, len(path) - 9) & ! & Format(Today(),"MMddyyyy")

'execute command
Try
cmd2 = New SqlCommand(strQuery2, con2)
cmd2.CommandTimeout = 6000 ' #### oder hier setzen das timout ?????? 03.09.2019 ????????
cmd2.ExecuteNonQuery()
MessageBox.Show("Database " & database2 & " Wurde erfolgreich wiederhergestellt.", "Nachricht", MessageBoxButtons.OK, MessageBoxIcon.Information)
con2.Close()
con2.Dispose() '### TM 30.10.2017 - Fehler: Exclusive access could not be obtained because the database is in use. Restore Database is terminating abnormally - Resourcen Freigeben!!!!
Cursor = Cursors.Default
Catch ex As Exception
Cursor = Cursors.Default
MessageBox.Show(ex.Message, "Nachricht", MessageBoxButtons.OK, MessageBoxIcon.Information)
End Try
'con2.Close() '### 17.04.2019
'con2.Dispose()
End If
Catch ex As Exception
Cursor = Cursors.Default
MessageBox.Show(ex.Message, "Nachricht", MessageBoxButtons.OK, MessageBoxIcon.Information)
End Try
'con2.Close() '### 17.04.2019
'con2.Dispose()


End Sub

Gruss Meier Thomas

Hallo hab mal rumprobiert...

constr2 = "Data Source=" & get_servername2 & ";Initial Catalog=master; Integrated Security=True"

Dann bekomme ich die Meldung erfolgreich wieder hergestellt.

Gruss Meier Thomas