Check dropped files by hash instead of filename #GI-12

Global_Indexer/ClassFilehandle.vb

@@ -144,8 +144,21 @@ Public Class ClassFilehandle
         Try
             filename = filename.Replace("'", "''")
 
+            Dim oHash As String
+
+            If File.Exists(filename) Then
+                Try
+                    oHash = FILESYSTEM.GetChecksum(filename)
+                Catch ex As Exception
+                    LOGGER.Error(ex)
+                    oHash = String.Empty
+                End Try
+            Else
+                oHash = String.Empty
+            End If
+
             Dim filename_only As String = Path.GetFileName(filename)
-            Dim ins As String = "INSERT INTO TBGI_FILES_USER (FILENAME2WORK, USER@WORK,HANDLE_TYPE,FILENAME_ONLY) VALUES ('" & filename & "','" & Environment.UserName & "','" & handleType & "','" & filename_only & "')"
+            Dim ins As String = $"INSERT INTO TBGI_FILES_USER (FILENAME2WORK, USER@WORK, HANDLE_TYPE, FILENAME_ONLY, FILE_HASH) VALUES ('{filename}','{Environment.UserName}','{handleType}','{filename_only}', '{oHash}')"
             Return ClassDatabase.Execute_non_Query(ins, True)
 
         Catch ex As Exception
@@ -157,7 +170,7 @@ Public Class ClassFilehandle
         ' Prüft, ob die angegeben Datei aktuell durch eine
         ' andere Anwendung in Benutzung ist
         Dim ff As Integer = FreeFile()
-        If System.IO.File.Exists(fullFilePath) Then
+        If File.Exists(fullFilePath) Then
             Try
                 ' Versuchen, die Datei mit *exklusiven* Lese- und
                 ' Schreibrechten zu öffnen