如何查询EF代码第一个数据库

Question

当我解决出现InvalidOperationException

查询：

var user = db.Users.FirstOrDefault(u => u.Email.Equals(username) && u.Password.Equals(password)); 

错误：

Local = 'db.Users.Local' threw an exception of type 'System.InvalidOperationException' 

详细的错误信息：

Message = "The context cannot be used while the model is being created. This exception may be thrown if the context is used inside the OnModelCreating method or if the same context instance is accessed by multiple threads concurrently. Note that instance members of D... Source: ""entityframework" StackTrace:StackTrace = " at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()\r\n at System.Data.Entity.Internal.InternalContext.Initialize()\r\n at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)\r\n at System...

Answer 1

您可以设置MultipleActiveResultSets=true;在您的连接字符串

您应该注意以下错误消息：

o r if the same context instance is accessed by multiple threads同时发生。

yourcontext context = new yourcontext(); 

var user = context.Users.FirstOrDefault(u => u.Email.Equals(username) && u.Password.Equals(password)); 

这里使用的情况下，你必须处理像