更新过程运行后如何立即重新查询更新的值 [英] How to requery updated values immediately after update procedure runs

问题描述

据我所知，以下代码对"MySite"进行的数据库更改是立即进行的:

As far as I can tell, changes made to the database by the following code to "MySite" are immediate:

  public List<vcData> UpdateDisplayAndUrl(List<vcData> vcDataList)
    {
        foreach (vcData vcData in vcDataList)
        {
            _entities.ExecuteStoreCommand("UPDATE vcData SET DisplayItem = {0}, DisplayUrl = {1} WHERE ID = {2} ", vcData.DisplayItem, vcData.DisplayUrl, vcData.ID);
        }                   
        return GetTableData();
    }

我想做的是立即返回新更新的记录以进行进一步处理，本质上是重新查询刚刚进行的更改:

What I would like to do is to immediately return the newly updated records for further processing, essentially, re-query the changes that have just been made:

    public List<vcData> GetTableData()
    {  
        var result = (from td in _entities.vcData
                      where td.SiteID == "MySite" 
                      select td).ToList();
        return result;
    }  

在我的控制器代码中，我正在尝试执行以下操作:

In my controller code, I am trying to do something like:

_currentvcTickerDataList = Repository.UpdateDisplayAndUrl(vcUnupdatedDataList);
//.....do more stuff with _currentvcTickerDataList, which ought to contain updated information, should it not?

问题:GetTableData()方法似乎不返回更新后的值，而仅返回先前(未更新)的值.

PROBLEM: the GetTableData() method does not seem to return the updated values, only the previous (unupdated) values.

我是LINQ，实体框架和MVC的新手，所以我可以肯定我缺少一些基本知识.

I am new to LINQ, entity framework, and MVC, so I'm pretty certain there is something fundamental that I am missing.

推荐答案

在查询之前，您需要将MergeOption设置为OverwriteChanges.请仔细阅读 msdn 中所述的MergeOption，有个清楚的主意.

You need to set the MergeOption to OverwriteChanges before querying. Please go through the MergeOptions explained in msdn to get a clear idea.

public List<vcData> GetTableData()
{
    var currentMergeOption =  _entities.vcData.MergeOption;
    _entities.vcData.MergeOption = MergeOption.OverwriteChanges;

    var result = (from td in _entities.vcData
                  where td.SiteID == "MySite" 
                  select td).ToList();

    //revert the change
    _entities.vcData.MergeOption = currentMergeOption;

    return result;
} 

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