vb.net数据库连接破坏了Windows窗体

Question

HY，

我在Visual Studio 2015项目中使用Access数据库连接。不幸的是，如果使用该功能，我的Windows窗体在调试模式下不再正确显示。如果我不使用数据库连接一切正常 - 我认为我的连接有任何错误（字符串）？

Imports System.Data.OleDb

Module Datenbank
    Private Const Provider As String = "Provider=Microsoft.ACE.OLEDB.12.0;"

    Public Sub InitDbParameter(ByRef Con As OleDbConnection, ByRef Cmd As OleDbCommand)
        Con.ConnectionString = Provider & "Data Source =" & Db
        Cmd.Connection = Con
    End Sub

 Public Sub FillDGVMitarbeiter(ByRef DGV As DataGridView)
        Dim Con As New OleDbConnection
        Dim Cmd As New OleDbCommand
        Dim Reader As OleDbDataReader
        Dim i As Integer
        Dim ID As String

        InitDbParameter(Con, Cmd)
        Con.Open()
        Cmd.CommandText = "SELECT * FROM Mitarbeiter WHERE gelöscht= false;"

        Try
            Reader = Cmd.ExecuteReader()
            DGV.RowCount = 0
            Do While Reader.Read = vbTrue
                i = DGV.RowCount
                With DGV
                    .RowCount = i + 1
                    .Item("MitarbeiterID", i).Value = Reader("ID").ToString
                    .Item("MAVorname", i).Value = Reader("Vorname").ToString
                    .Item("MANachname", i).Value = Reader("Nachname").ToString
                    .Item("MaKürzel", i).Value = Reader("MA_Kürzel").ToString
                    .Item("MaEintrittsdatum", i).Value = Mid(Reader("Eintrittsdatum").ToString, 1, 10)
                    .Item("MaAustrittsdatum", i).Value = Mid(Reader("Austrittsdatum").ToString, 1, 10)
                End With
            Loop
            Reader.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try


        Con.Close()
    End Sub

Application without DB connection

Application with DB connection and destroyed Form