如何使用QueryOver返回通用列表

I'm trying to do a simple select with queryover and get a generic list.

我正在尝试使用queryover进行简单的选择并获得通用列表。

I want to get from the table only username, email and firstname and omit the rest.

我想从表中只获取用户名,电子邮件和名字,并省略其余部分。

This is my code:

这是我的代码:

public IList<Users> GetAllByRole(string role)
{
    var users= this.Session.QueryOver<Users>()
        .where(f => f.role == role)
        .select(f => f.username)
        .select(f => f.email)
        .select(f => f.firstname)
        .list<Users>();

    return users;
}

Error:

The value \"x\" is not of type \"Model.Poco.Entities.Users\" and cannot be used in this generic collection.\r\nParameter name: value

值“x”不是类型“Model.Poco.Entities.Users”,并且不能在此通用集合中使用。\ r \ nParameter name:value

SQL Query would be something like this

SQL Query就是这样的

SELECT [username]
  ,[email]
  ,[firstname]
FROM [MyDB].[dbo].[MyTable]
WHERE [role] = 'admin'

I also tried something like this

我也试过这样的事

IList<Users> users = this.Session.QueryOver<Users>()
            .Where(p => p.role == role)
            .SelectList(list => list
                    .Select(p => p.username)
                    .Select(p => p.email)
                    .Select(p => p.firstname)
            )
            .List<Users>();
return users;

Error:

The value \"System.Object[]\" is not of type \"Poco.Entities.Users\" and cannot be used in this generic collection.\r\nParameter name: value

值“System.Object [] \”的类型不是“Poco.Entities.Users”,并且不能在此通用集合中使用。\ r \ nParameter name:value

1 个解决方案

#1

We need to add 1) aliases to each column and use 2) transformer:

我们需要为每列添加1)别名并使用2)变换器:

// Users u - will serve as an alias source below
Users u = null;
IList<Users> users = this.Session.QueryOver<Users>()
        .Where(f => f.role == role)
        .SelectList(list => list        // here we set the alias 
                .Select(p => p.username) .WithAlias(() => u.username)
                .Select(p => p.email)    .WithAlias(() => u.email)
                .Select(p => p.firstname).WithAlias(() => u.firstname)
        )
        // here we Transform result with the aliases into Users
        .TransformUsing(Transformers.AliasToBean<Users>())
        .List<Users>();