检测修改记录与新记录，并使用 ASP.NET MVC 2、EF v4、POCO 和存储库模式更新修改记录

Question

我正在使用 ASP.NET MVC 2、实体框架 v4、ADO.NET C# POCO 实体生成器和存储库模式。很多流行语！

设置：

我有一个存储库，IPartiesRepository。我有一个 Party 对象和一个 *Party_Identification* 对象。政党是个人或组织的通用术语。

在 SQL/物理模型级别，Party 表有一个主键 PartyId。 Party_Identifications 表有一个由三个字段组成的复合键：PartyId、IdentificationTypeCode 和IdentificationStartDate。

我有一个强类型（对于政党）视图，其中列出了政党信息和相关标识。用户可以编辑一方的身份；编辑链接是通过 ActionLink 生成的，如下所示：

<h3>Identification Data</h3>
<% foreach (var Identification in Model.Party_Identifications) { %>
   <%: Identification.IdentificationTypeCode %>: <%: Identification.IdentificationValue %> - <%: Html.ActionLink("Edit", "EditIdentification", new { partyId = Identification.PartyId, idTypeCode = Identification.IdentificationTypeCode, startDate = Identification.PartyIdentificationStartDate })%><br />
<% } %>

PartyController 中的 EditIdentification() 方法如下所示：

public ActionResult EditIdentification(int partyId, string idTypeCode, string startDate)
{
    var party = partiesRepository.GetPartyById(partyId);
    var identification = party.Party_Identifications.Where(x => x.PartyId == partyId && x.IdentificationTypeCode == idTypeCode && x.PartyIdentificationStartDate == DateTime.Parse(startDate)).First();
    return View("EditIdentification", identification);
}

EditIdentification 视图允许用户通过基本表单修改标识记录：

<% using (Html.BeginForm("EditIdentification", "Party")) { %>
<%: Html.EditorForModel()%>
<input type="submit" value="Save" />
<% } %>

问题：

我在 PartyController 中有另一个处理保存的 EditIdentification() 方法。我试图查看我们是否正在更新现有的标识记录，或创建一个新的标识记录（我在 PartyController 中还有一个 Create() 方法，它返回 < em>EditIdentification 视图，以 Party_Identification 对象作为模型）。

我知道有一种更好的方法可以完成我下面正在做的事情（具体来说，检测修改的记录与新记录，并更新修改的记录）——我该如何改进？

[HttpPost]
public ActionResult EditIdentification(Party_Identification partyidentification)
{
    TryUpdateModel(partyidentification);
    if (partyidentification.CreationDate == DateTime.Parse("01/01/0001"))
    {
        partyidentification.CreationDate = DateTime.Now;
        partyidentification.CreatedByName = User.Identity.Name.ToString();
        partyidentification.ModificationDate = DateTime.Now;
        partyidentification.ModifiedByName = User.Identity.Name.ToString();
    }

    // TODO: Validation goes here...

    if (ModelState.IsValid)
    {
        var party = partiesRepository.GetPartyById(partyidentification.PartyId) as Party;
        int partyCount = party.Party_Identifications
            .Where(x => x.PartyId == partyidentification.PartyId &&
                   x.IdentificationTypeCode == partyidentification.IdentificationTypeCode &&
                   x.PartyIdentificationStartDate == partyidentification.PartyIdentificationStartDate)
            .Count();
        if (partyCount == 0)
        {
            party.Party_Identifications.Add(partyidentification);
        }
        else
        {
            var idtoupdate = party.Party_Identifications
            .Where(x => x.PartyId == partyidentification.PartyId && 
                        x.IdentificationTypeCode == partyidentification.IdentificationTypeCode && 
                        x.PartyIdentificationStartDate == partyidentification.PartyIdentificationStartDate)
            .First();
            idtoupdate.IdentificationValue = partyidentification.IdentificationValue;
            idtoupdate.PartyIdentificationEndDate = partyidentification.PartyIdentificationEndDate;
            idtoupdate.ModificationDate = DateTime.Now;
            idtoupdate.ModifiedByName = User.Identity.Name.ToString();
        }
        partiesRepository.SaveParty(party);

        return View("Edit", party);
    }
    else
    {
        return View("Edit", partyidentification);
    }
}

Answer 1

您似乎在重复不需要的代码：

if (ModelState.IsValid)
            {
                var party = partiesRepository.GetPartyById(partyidentification.PartyId) as Party;

                int partyCount = party.Party_Identifications
                    .Where(x => x.PartyId == partyidentification.PartyId &&
                           x.IdentificationTypeCode == partyidentification.IdentificationTypeCode &&
                           x.PartyIdentificationStartDate == partyidentification.PartyIdentificationStartDate)
                           .first();

                if (partyCount == null)
                {
                    party.Party_Identifications.Add(partyidentification);
                }
                else
                {
                    partyCount.IdentificationValue = partyidentification.IdentificationValue;
                    partyCount.PartyIdentificationEndDate = partyidentification.PartyIdentificationEndDate;
                    partyCount.ModificationDate = DateTime.Now;
                    partyCount.ModifiedByName = User.Identity.Name.ToString();
                }
                partiesRepository.SaveParty(party);

                return View("Edit", party);
            }
            else
            {
                return View("Edit", partyidentification);
            }