C# 使用实体框架更新列表项的最有效方法

我们的用户将有一个列表集合，其中只有一个将标记为boolIsPrimary=true

我想写实体框架代码来更新它

大概是这样的：

UPDATE dbo.EmailRecords 
SET IsPrimary = 1
WHERE EmailRecordId = @RecordId

UPDATE dbo.EmailRecords 
SET IsPrimary = 0 
WHERE EmailRecordId != @RecordId
     AND ParentRecordId = @ParentRecordId

foreach (var thisRecord in profile.EmailRecords)
{
    if (thisRecord.EmailRecordId == thisId)
    {
        thisRecord.IsPrimary = true;
    }
    else
    {
        thisRecord.IsPrimary = false;
    }
}

db.SaveChanges();

我的目标是：

public class EmailRecords
{
    public int EmailRecordId { get; set; }
    public int ParentRecordId { get; set; }
    public string EmailAddress { get; set; }
    public bool IsPrimary { get; set; }
}

如何使用实体框架实现这一点

我在考虑这样做：

UPDATE dbo.EmailRecords 
SET IsPrimary = 1
WHERE EmailRecordId = @RecordId

UPDATE dbo.EmailRecords 
SET IsPrimary = 0 
WHERE EmailRecordId != @RecordId
     AND ParentRecordId = @ParentRecordId

foreach (var thisRecord in profile.EmailRecords)
{
    if (thisRecord.EmailRecordId == thisId)
    {
        thisRecord.IsPrimary = true;
    }
    else
    {
        thisRecord.IsPrimary = false;
    }
}

db.SaveChanges();

---

有没有更干净的方法可以做到这一点？

使用您给出的示例模型

public class EmailRecords
{
    public int EmailRecordId { get; set; }
    public int ParentRecordId { get; set; }
    public string EmailAddress { get; set; }
    public bool IsPrimary { get; set; }
}

您可以使用LINQ和代码的组合来取消设置此主要行为

// Change this Int32 to match your @RecordId and @ParentRecordId.  Possibly parameterize this entire code snippet into a method.
Int32 recordIdToChange = 1;
Int32 parentRecordIdToChange = 1;

// Set the new primary.
EmailRecords emailRecordToSetToPrimary = profile.EmailRecords.Where(cs => cs.EmailRecordId == recordIdToChange).FirstOrDefault();
if (emailRecordToSetToPrimary != null){
   emailRecordToSetToPrimary.IsPrimary = true;
}

// Only unset those records whose id does not match the new primary AND is currently set as a primary.
List<EmailRecords> emailRecordsToUnsetFromPrimary = profile.EmailRecords.Where(cs => cs.EmailRecordId != recordIdToChange && cs.IsPrimary == true && cs.ParentRecordId == parentRecordIdToChange).ToList();
foreach (EmailRecords emailRecordToUnsetFromPrimary in emailRecordsToUnsetFromPrimary){
   emailRecordToUnsetFromPrimary.IsPrimary = false;
}

// Perform your save on the emailRecords list collection.

---

你是在寻找C代码，类似这样的东西吗

foreach(var record in profile.EmailRecords)
{
    record.IsPrimary = record.EmailRecordId == recordId;
}

---

您的.net列表集合的名称是什么？提供一些代码。您是指linq2sql还是实体框架？您好。所以你可能已经注意到在这个问题上有几张反对票了。原因是这个问题现在听起来像是这个想法，请给我编码。为了得到一个好的答案，你应该先尝试自己做一些事情，如果你遇到了具体的问题，然后在这里发布，所以这个问题听起来像是我有这个问题，试图解决它，但得到了这个错误/issueThis emailRecords.Wherecs=>cs.EmailRecordId==recordIdToChange.FirstOrDefault；还可以进一步简化为emailRecords.FirstOrDefaultcs=>cs.EmailRecordId==recordIdToChange；-不需要。首先在哪里，然后是。第一个或默认值之后。。。