Question

我们的用户将拥有List<EmailRecords>个集合，其中只有一个会被标记为(bool)IsPrimary = true。

我想编写实体框架代码来更新它。

这样的事情：

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

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

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Entity Framework执行此操作？

我正在考虑做这样的事情：

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

db.SaveChanges();

有更简洁的方法吗？

Answer 1

您是否正在寻找C＃代码，这些内容是什么？

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

Answer 2

使用您已经给出的示例模型。

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.

使用Entity Framework更新列表项的最有效方法

2 个答案: