如何在另一个方法中调用两个linq查询

本文介绍了如何在另一个方法中调用两个linq查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我的存储库类中有两个查询，每个查询都调用不同的用户组。我想在下面的身份验证方法中调用这两个查询，但我不太确定，我将如何这样做呢？我目前有一个查询调用身份验证方法，但我想知道，我怎么能调用这两个查询。我是否需要将查询分组在一起，如果是，如何？ 存储库类：

public Cust trial_test（ string 用户名，字符串密码） { var query = from s in db.Subscriptions join u 在中.s.sUID上的db.UserDetails等于u.uID 其中 s.ExpiryDate > = DateTime.Now&& s.sPID.Value == 163 && s.All.Value！= true && u.uUsername == username&& u.uPassword ==密码 选择 u; return query.FirstOrDefault（）; } public Cust full_test（ string username， string password） { var query = 来自 s db.Subscriptions join u db.UserDetails等于u.uID 其中​​ s.ExpiryDate > = DateTime.Now&& s.sPID.Value == 163 && s.All.Value == true && u.uUsername == username&& u.uPassword ==密码 选择 u; return query.FirstOrDefault（）; }

身份验证方法：

Cust user = repository.trial_test（凭证[ 0 ]，凭证[ 1 ]）; if （user == null ） { var resp = new HttpResponseMessage（HttpStatusCode.Unauthorized ） { Content = new StringContent（ string .Format（ 访问被拒绝）），}; return 未经授权（请求）; } else { IPrincipal principal = new GenericPrincipal（ new GenericIdentity（user.Username，BasicAuthResponseHeaderValue）， null ）; Thread.CurrentPrincipal = principal; HttpContext.Current.User = principal; } return base .SendAsync（request，cancellationToken）;

请帮忙。任何建议，将非常感谢。非常感谢。

解决方案

尝试在你的函数中使用可选参数这样

public Cust trial_test（string username，string password，int group = 0） { if（group == 0） { var query =来自db.Subscriptions中的s 在s.sUID上的db.UserDetails中加入u等于u.uID 其中s.ExpiryDate> = DateTime.Now&& s.sPID.Value == 163&& s.All.Value！= true&& u.uUsername == username&& u.uPassword ==密码选择你; 返回query.FirstOrDefault（）; } 其他 { var query =来自db.Subscriptions中的s 在s.sUID上的db.UserDetails中加入u等于u.uID 其中s.ExpiryDate> = DateTime.Now&& s.sPID.Value == 163&& s.All.Value == true&& u.uUsername == username&& u.uPassword ==密码选择你; 返回query.FirstOrDefault（）; } } Cust用户= repository.trial_test（凭证[0]，凭证[1]，组：1）;

//将值1传递给组以执行第二个查询，否则它将调用第一个查询。

在两个查询中唯一的区别是

s.All.Value！= true

子句。如果是这种情况，那么下面的一个linq将起作用，考虑到s.All.Value是真还是假

public Cust trial_test（字符串用户名，字符串密码，bool spidFlag ） { var query =来自db.Subscriptions中的s 在s.sUID上的db.UserDetails中加入u等于u.uID 其中s.ExpiryDate> = DateTime.Now&& s.sPID.Value == 163&& s.All.Value == spidFlag&& u.uUsername == username&& u.uPassword ==密码选择你; 返回query.FirstOrDefault（）; }

Hi, I have two queries in my repository class and each of them call different group of users. I would like to call the two queries in my authentication method below, but I am little unsure, how would I go about doing this so? I currently have one query calling authentication method below but I would like to know, how can I call both of the queries. Would I need to group my queries together, if so, how? Repository class:

public Cust trial_test(string username, string password) { var query = from s in db.Subscriptions join u in db.UserDetails on s.sUID equals u.uID where s.ExpiryDate >= DateTime.Now && s.sPID.Value == 163 && s.All.Value != true && u.uUsername == username && u.uPassword == password select u; return query.FirstOrDefault(); } public Cust full_test(string username, string password) { var query = from s in db.Subscriptions join u in db.UserDetails on s.sUID equals u.uID where s.ExpiryDate >= DateTime.Now && s.sPID.Value == 163 && s.All.Value == true && u.uUsername == username && u.uPassword == password select u; return query.FirstOrDefault(); }

Authentication method:

Cust user = repository.trial_test(credentials[0], credentials[1]); if (user == null) { var resp = new HttpResponseMessage(HttpStatusCode.Unauthorized) { Content = new StringContent(string.Format("access denied")), }; return Unauthorized(request); } else { IPrincipal principal = new GenericPrincipal(new GenericIdentity(user.Username, BasicAuthResponseHeaderValue), null); Thread.CurrentPrincipal = principal; HttpContext.Current.User = principal; } return base.SendAsync(request, cancellationToken);

Please help. Any advice, would be very much appreciated. Many thanks.

解决方案

try to make use of optional parameter in your function like this

public Cust trial_test(string username, string password, int group = 0) { if (group == 0) { var query = from s in db.Subscriptions join u in db.UserDetails on s.sUID equals u.uID where s.ExpiryDate >= DateTime.Now && s.sPID.Value == 163 && s.All.Value != true && u.uUsername == username && u.uPassword == password select u; return query.FirstOrDefault(); } else { var query = from s in db.Subscriptions join u in db.UserDetails on s.sUID equals u.uID where s.ExpiryDate >= DateTime.Now && s.sPID.Value == 163 && s.All.Value == true && u.uUsername == username && u.uPassword == password select u; return query.FirstOrDefault(); } } Cust user = repository.trial_test(credentials[0], credentials[1],group:1);

//pass the value 1 to the group to execute the second query else it will call the first one.

in both the queries only difference is the

s.All.Value != true

clause. If this is the case then one linq like below will work, considering s.All.Value is either true or false

public Cust trial_test(string username, string password, bool spidFlag) { var query = from s in db.Subscriptions join u in db.UserDetails on s.sUID equals u.uID where s.ExpiryDate >= DateTime.Now && s.sPID.Value == 163 && s.All.Value == spidFlag && u.uUsername == username && u.uPassword == password select u; return query.FirstOrDefault(); }