在子查询LINQ中选择一个元素(Select One element in a subquery LINQ)
我正在使用LINQ从数据库中提取数据,并且有一个关于从子查询中提取对象的问题。 这是我正在拉的班级:
public class Users { public Users() { SerialNumbers = new HashSet<SerialNumbers>(); } /// <summary> /// The User's Unique Id /// </summary> public Guid Id { get; set; } /// <summary> /// The Users name /// </summary> public string Name { get; set; } /// <summary> /// The Users email. This can be null/empty string /// </summary> public string Email { get; set; } public virtual ICollection<SerialNumbers> SerialNumbers { get; set; } }如何从Serial Numbers集合中选择第一个元素,而不是整个集合本身?
谢谢
I am using LINQ to pull data from a database and have a question about pulling an object from a subquery. This is the class that I am pulling:
public class Users { public Users() { SerialNumbers = new HashSet<SerialNumbers>(); } /// <summary> /// The User's Unique Id /// </summary> public Guid Id { get; set; } /// <summary> /// The Users name /// </summary> public string Name { get; set; } /// <summary> /// The Users email. This can be null/empty string /// </summary> public string Email { get; set; } public virtual ICollection<SerialNumbers> SerialNumbers { get; set; } }How do I select the first element from the Serial Numbers collection and not the whole collection itself?
Thanks
最满意答案
您应该创建一个DataTransferObject并映射到它:
context.Users.Select(x => new UserDto { Id = x.Id, Name = x.Name, Email = x.Email, SerialNumber = x.SerialNumbers.FirstOrDefault() });You should make a DataTransferObject and map to it:
context.Users.Select(x => new UserDto { Id = x.Id, Name = x.Name, Email = x.Email, SerialNumber = x.SerialNumbers.FirstOrDefault() });更多推荐
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