主题：不需要的编辑的内容保留原有数据

Dim e As RequestEventArgs = args(0)
Dim wb As New weui
Dim PageNumber As Integer = e.GetValues("page")
Dim PrimaryKey As Integer = e.GetValues("key")
Dim PageURL = "List.htm?page=" & PageNumber
If e.PostValues.Count = 0 Then '生成编辑页面
    Dim dr As DataRow = DataTables("订单").SQLFind("[_Identify]=" & PrimaryKey)
    If dr IsNot Nothing Then
        wb.AddForm("","form1","edit.htm?key=" & PrimaryKey &  "&page=" & PageNumber)
        With wb.AddInputGroup("form1","ipg1","编辑订单")
            .AddInput("产品","产品","text").Value = dr("产品")
            .AddInput("客户","客户","text").Value = dr("客户")
            .AddInput("数量","数量","number").Value = dr("数量")
            With .AddInput("单价","单价","number")
                .Step="0.01"
                .Value = dr("单价")
            End With
            .AddInput("日期","日期","date").Value = dr("日期")
        End With
        With wb.AddButtonGroup("form1","btg1",True)
            .Add("btn1", "确定", "submit")
        End With
    Else
        With wb.AddMsgPage("","msgpage","编辑失败", "此订单可能已经被删除!") '提示用户此订单不存在.
            .icon= "Warn"
            .AddButton("btn1","返回",PageURL) '生成返回原来页面的按钮
        End With
    End If
Else '保存编辑结果
    Dim dr As DataRow = DataTables("订单").SQLFind("[_Identify]=" & PrimaryKey)
    If dr IsNot Nothing Then
        Dim nms() As String = {"产品","客户","数量","单价","日期"}
        For Each nm As String In nms
            dr(nm) = e.PostValues(nm)
        Next
        dr.Save()
        '显示完成提示,2妙手自动返回原来的页面
        wb.AppendHtml("<meta http-equiv='refresh' c>",True)
        wb.AddToast("","t1", "编辑完成",0).Visible = True
    Else
        With wb.AddMsgPage("","msgpage","保存失败", "此订单可能已经被删除!") '提示用户此订单不存在.
            .icon= "Warn"
            .AddButton("btn1","返回",PageURL) '生成返回原来页面的按钮
        End With
    End If
End If
e.WriteString(wb.Build) '生成网页

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帮助中如果重新编辑保存就会代表重新写入数据  但是有100列  我只需要修改和编辑10行  现代的代码就会只有当前编辑的10行数据会更新，那么其余的行就会被清除数据  

我想要如何保护原来的历史数据。而不被删除