使用 linq toEntity 获取新添加记录的 ID

发布于 2024-11-02 03:17:28 字数 687 浏览 1 评论 0原文

您好，这是我使用 linq toEntity 的第一个项目。我已经弄清楚如何创建新记录，我只需要获取分配给它的 ID，这样当我在扩展表中添加条目时，我就可以将它用作扩展表中的 FK。我允许用户创建请求，该请求可以针对多个设备，因此我有一个 Request 和 RequestedEquipment 表。以下是我用来创建请求的代码：

public void addReq(ReqType reqType, Employee reqBy, Location loc, string comm)
        {
            int reqID;
            Request req = new Request();
            req.Comments = comm;
            req.Employee = reqBy;
            req.ReqType = reqType;
                req.RequestStatus = findReqStat(1);
            req.Location = loc;
            entities.AddToRequests(req);
            entities.SaveChanges();
        }

如何获取已创建的请求的 ID，以便我可以使用它在 RequestedEquipment 表中创建所需的条目？

原文

Hi this is my first project using linq to entities. I've figured out how to create a new record I just need to get the ID that was assigned to it so I can use it as a FK in an extension table when I add the entries there. I'm allowing users to create request, the request can be for multiple pieces of equipment so I have a Request and RequestedEquipment table. Here is the code I'm using to create the request:

public void addReq(ReqType reqType, Employee reqBy, Location loc, string comm)
        {
            int reqID;
            Request req = new Request();
            req.Comments = comm;
            req.Employee = reqBy;
            req.ReqType = reqType;
                req.RequestStatus = findReqStat(1);
            req.Location = loc;
            entities.AddToRequests(req);
            entities.SaveChanges();
        }

How can I get the ID of the request that was created so I can use it to Create the needed entries in the RequestedEquipment Table?

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半窗疏影 2024-11-09 03:17:28

在调用 SaveChanges() 后，您应该能够从新的 Request 对象中提取 ID 值，因此类似：

entities.SaveChanges();
reqID = req.ID;

SaveChanges() 应该将您的新记录保存到数据库，并且如果 ID 列设置为标识列DB，该自动生成的 ID 应通过实体框架传递回您的对象。

另外，为了以防万一，这里有一篇关于 ID 字段未自动更新问题的博客文章：
http:// dotnethacker.wordpress.com/2010/12/24/entity-framework-savechanges-doesnt-get-the- generated-identity-key/

You should be able to pull the ID value from your new Request object after the call to SaveChanges(), so something like:

entities.SaveChanges();
reqID = req.ID;

SaveChanges() should save your new record to the database, and if the ID column is set as an identity column in the DB, that auto-generated ID should be passed back into your object via the entity framework.

Also just in case here's a blog post on an issue where the ID field wasn't getting updated automatically:
http://dotnethacker.wordpress.com/2010/12/24/entity-framework-savechanges-doesnt-get-the-generated-identity-key/

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路还长，别太狂 2024-11-09 03:17:28

瑞安和迈克西托都是对的。但是，如果您需要通用解决方案，请查看以下函数：

public static T AddEntity<T>(T ent)
{
    Type t = typeof(T);

    try
    {
        using (Entities be = new Entities())
        {
            be.AddObject(t.Name, ent);
            be.SaveChanges();

            return ent;
        }
    }
    catch (Exception)
    {
        return default(T);
    }
}

通过这种方式，您可以创建所需的任何实体，并通过返回新创建的实体来找到其新 ID。 HTH。

Ryan and Mikecito are both right. However, if you need a generic solution take a look at the following function:

public static T AddEntity<T>(T ent)
{
    Type t = typeof(T);

    try
    {
        using (Entities be = new Entities())
        {
            be.AddObject(t.Name, ent);
            be.SaveChanges();

            return ent;
        }
    }
    catch (Exception)
    {
        return default(T);
    }
}

This way you can create any entity you need and by returning the newly created entity you find its new id. HTH.

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