?Public Class DBClass
    Inherits DBOperation
    Shared Sub DelClass(ByVal ClassName As String)
        Dim SQLString As String
        Dim MSG As String
        SQLString = "DELETE FROM tbClass WHERE ClassName ='" & ClassName & "'"
        DBOperate(SQLString, MSG)
    End Sub



    Shared Function AddClass(ByVal ClassName As String) As Boolean
        Dim SQLString As String
        Dim MSG As String
        SQLString = "SELECT * FROM tbClass WHERE ClassName='" & ClassName & "'"
        Dim UserTable As DataTable = DBOperation.DBOperate(SQLString, MSG)
        If UserTable.Rows.Count >= 1 Then    '判斷用戶是否存在
            MsgBox("輸入的班級名稱已存在，請重試", MsgBoxStyle.Exclamation, "信息框")
            Return False
        Else
            SQLString = "INSERT INTO tbClass VALUES('" & ClassName & "','" & Date.Now & "')"
            DBOperate(SQLString, MSG)
            Return True
        End If
    End Function

    Shared Function LoadClass() As DataTable
        Dim SQLString As String
        Dim MSG As String
        SQLString = "SELECT ClassName AS 班級名稱, CreateDate AS 創建日期  FROM tbClass"
        Return DBOperate(SQLString, MSG)
    End Function
End Class