在Web服务中使用LINQ to SQL [英] usign LINQ to SQL in web service

问题描述

我需要从Web服务返回此查询结果，该怎么办?
注意:请勿循环访问结果数据或填充另一个数据表.

I need to return this query result from web service, how can I do that ?
notice : without looping on result data or filling another datatable.

var query = from usr in BCM.Users
                    join usrgrp in BCM.UsersGroups
                    on usr.userID equals usrgrp.userID
                    where usrgrp.groupID == ID
                    select new { usr.firstName, usr.FamilyName, usr.userName,
                    usrgrp.Group.groupName, usrgrp.Group.groupDescription };

推荐答案

您好，

一种可能的方式是定义一个数据实体，您可以在选择语句中填写该数据实体:

实体:

Hello,

One possible way would be that you define a data-entity which you can fill-in in your select statement:

The entity:

public class UserEntity
{
    public string Firstname { get; set; }
    public string Familyname { get; set; }
    public string Username { get; set; }
    public string GroupName { get; set; }
    public string GroupDescription { get; set; }
}

选择块:

The select block:

var query = from usr in BCM.Users
	join usrgrp in BCM.UsersGroups
	on usr.userID equals usrgrp.userID
	where usrgrp.groupID == ID
	select new UserEntity {
		Firstname = usr.firstName, Familyname = usr.FamilyName, Username = usr.userName,
		GroupName = usrgrp.Group.groupName, GroupDescription = usrgrp.Group.groupDescription
	};

然后，您可以将值返回为:

Then you could return the value as:

return query.FirstOrDefault();

(这将返回一个强类型的UserEntity对象)
或

(This returns a strong-typed UserEntity object)
or

return query.ToList();

(这将返回一个强类型List<UserEntity>)

另一种方法是直接将生成的匿名对象转换为Xml或Json表示形式(取决于您可以用作Web服务的输出)，并返回序列化的字符串.


希望这会有所帮助.

致以诚挚的问候，祝您编程愉快，
停止

(This returns a strong-typed List<UserEntity>)

Another way would be that you directly convert the resulting anonymous object to a Xml or Json representation (depends on what you can use as output of your webservice) and returns the serialized string.


Hope this helps.

Best regards and happy coding,
Stops

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