如何查詢EF代碼第一個數據庫

Question

當我解決出現InvalidOperationException

查詢：

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

錯誤：

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

詳細的錯誤信息：

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

您可以設置MultipleActiveResultSets=true;在您的連接字符串

您應該注意以下錯誤消息：

o r if the same context instance is accessed by multiple threads同時發生。

yourcontext context = new yourcontext(); 

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

這裏使用的情況下，你必須處理像