主题：[求助]请问设计窗口保存应用时为何出现这个错误提示

Dim t As Table = Tables("订单")
Dim g As Subtotalgroup
t.StopRedraw()
t.SubtotalGroups.Clear()
t.GroupAboveData = False
t.TreeVisible = False
t.SpillNode = True

g = New Subtotalgroup
g.Aggregate = AggregateEnum.Sum
g.GroupOn = "日期"
g.TotalOn = "数量,金额"
g.Caption = "小计 {0}月"
g.DateGroup = DateGroupEnum.Month
t.SubtotalGroups.Add(g)

g = New Subtotalgroup
g.Aggregate = AggregateEnum.Sum
g.GroupOn = "日期"
g.TotalOn = "数量,金额"
g.Caption = "截止 {0}月"
g.DateGroup = DateGroupEnum.Month
g.upto = True
t.SubtotalGroups.Add(g)

g = New Subtotalgroup
g.Aggregate = AggregateEnum.Sum
g.GroupOn = "产品"
g.TotalOn = "数量,金额"
g.Caption = "{0} 合计"
t.SubtotalGroups.Add(g)

g = New Subtotalgroup
g.Aggregate = AggregateEnum.Sum
g.GroupOn = "*"
g.TotalOn = "数量,金额"
g.Caption = "总计"
t.SubtotalGroups.Add(g)

t.Subtotal()
t.ResumeRedraw()
t.ShowCell(t.Rows.Count(True) - 1, 0) '显示最后一行