' Im Allgemeinen Teil
Dim IsProceed As Boolean 
 
Sub Sql_Query()
' Dein Code
End Sub
 
Private Sub btnNavNext_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles btnNavNext.Click
If IsProceed = True Then Exit Sub
IsProceed = True
Sql_Query()
Application.DoEvents()
IsProceed = False 
End Sub