asp.net-mvc – 如何优雅地重新附加Entity Framework 5 POCO结构

在应用程序中,用户经历多个屏幕,创建或编辑文档(称为“案例研究”).当他们到达最终屏幕时,他们的文档在内存中作为CaseStudy POCO存在,并且在将此结构保存到数据库之前一切都很好.

为了存储文档,我定义了几个数据库表,这些表又映射到业务层使用的EF POCO,然后由MVC控制器使用.因此,短期DbContexts用于检索POCO并将它们存储在请求之间的会话中.

因此,保存屏幕必须将具有导航属性的此POCO的内容保存到现有表数据(类别,布局和部分表),以及添加或更新的数据(CaseStudySections和CaseStudy本身).所以所有的POCO都是新的,或者用于检索它们的上下文早已被处理掉了.换句话说,它们都是“超然的”.

这篇文章的不寻常之处在于我已经掌握了可行的解决方案.问题是它体积大,脆而且不雅.我发布下面的代码.注意通过子集合的迭代,显式添加和附加,必须获得一个入口对象并将各个属性标记为已修改,以便它们将被更新,最后可怕的歌曲和舞蹈以使AdditionalMaterials集合同步.如果这是处理EF5中脱离的POCO所需要的,我会感到失望.

我在这里错过了什么吗？这与最佳做法一致吗？是否有更优雅和/或简洁的方法来附加POCO结构并插入/更新？

保存案例研究的代码：

public void SaveCaseStudy(CaseStudy caseStudy)
{
    foreach (var s in caseStudy.CaseStudySections)
    {
        this.Entities.Sections.Attach(s.Section);

        if (s.CreatedByRefId == default(Guid))
        {
            s.CreatedByRefId = this.UserRefId;
            s.CreatedTime = DateTime.Now;
            this.Entities.CaseStudySections.Add(s);
        }
        else
        {
            this.Entities.CaseStudySections.Attach(s);
            var entry = this.Entities.Entry(s);
            entry.Property(e => e.TextData).IsModified = true;
            entry.Property(e => e.BinaryData).IsModified = true;
        }

        s.LastModifiedByRefId = this.UserRefId;
        s.LastModifiedTime = DateTime.Now;
    }

    foreach (var m in caseStudy.AdditionalMaterials)
    {
        if (m.CreatedByRefId == default(Guid))
        {
            m.CreatedByRefId = this.UserRefId;
            m.CreatedTime = DateTime.Now;
            this.Entities.AdditionalMaterials.Add(m);
        }
        else
        {
            this.Entities.AdditionalMaterials.Attach(m);
        }

        m.LastModifiedByRefId = this.UserRefId;
        m.LastModifiedByTime = DateTime.Now;
    }

    this.Entities.Layouts.Attach(caseStudy.Layout);
    this.Entities.Categories.Attach(caseStudy.Category);

    if (caseStudy.CreatedByRefId != default(Guid))
    {
        this.Entities.CaseStudies.Attach(caseStudy);
        var entry = this.Entities.Entry(caseStudy);
        entry.Property(e => e.CaseStudyName).IsModified = true;
        entry.Property(e => e.CaseStudyTitle).IsModified = true;
    }
    else
    {
        this.Entities.CaseStudies.Add(caseStudy);
        caseStudy.CreatedByRefId = this.UserRefId;
        caseStudy.CreatedTime = DateTime.Now;
    }

    caseStudy.LastModifiedByRefId = this.UserRefId;
    caseStudy.LastModifiedTime = DateTime.Now;

    if (caseStudy.CaseStudyStatus != (int)CaseStudyStatus.Personalized)
    {
        caseStudy.CaseStudyStatus = (int)CaseStudyStatus.PendingApproval;
    }

    caseStudy.ApprovedByRefId = null;
    caseStudy.ApprovedTime = null;
    this.Entities.SaveChanges();

    var existingAdditionalMaterialRefIds = caseStudy.AdditionalMaterials
        .Select(m => m.AdditionalMaterialRefId)
        .ToArray();

    var additionalMaterialsToRemove = this.Entities.AdditionalMaterials
        .Where(m => 
            m.CaseStudyRefId == caseStudy.CaseStudyRefId && 
            !existingAdditionalMaterialRefIds.Contains(m.AdditionalMaterialRefId))
        .ToArray();

    foreach (var additionalMaterialToRemove in additionalMaterialsToRemove)
    {
        this.Entities.AdditionalMaterials.Remove(additionalMaterialToRemove);
    }

    this.Entities.SaveChanges();
}