實體框架 - 期待'providerInvariantName'參數的非空字符串

Question

好的，這可能與EF無關。我想使用代碼優先功能和下面是我寫的： -

var modelBuilder = new ModelBuilder(); 
      var model = modelBuilder.CreateModel(); 
      using (AddressBook context = new AddressBook(model)) 
      { 
       var contact = new Contact 
       { 
        ContactID = 10000, 
        FirstName = "Brian", 
        LastName = "Lara", 
        ModifiedDate = DateTime.Now, 
        AddDate = DateTime.Now, 
        Title = "Mr." 

       }; 
       context.contacts.Add(contact); 
       int result = context.SaveChanges(); 
       Console.WriteLine("Result :- "+ result.ToString()); 

      } 

的上下文類： -

public class AddressBook : DbContext 
    { 
     public AddressBook() 
     { } 
     public AddressBook(DbModel AddressBook) 
      : base(AddressBook) 
     { 

     } 
     public DbSet<Contact> contacts { get; set; } 
     public DbSet<Address> Addresses { get; set; } 
    } 

和連接字符串： -

<?xml version="1.0" encoding="utf-8" ?> 
<configuration> 
    <connectionStrings> 
    <add name="AddressBook" connectionString="Data Source=MyMachine;Initial Catalog=AddressBook;Integrated Security=True;MultipleActiveResultSets=True;providerName=System.Data.SqlClient"/> 
    </connectionStrings> 
</configuration> 

所以，數據庫名稱是「AddressBook」，當我初始化AddressBook對象時發生錯誤。我看到有人建議將（providerName =「System.Data.SqlClient」）添加到連接字符串中。但它不適用於我的情況。我在這裏錯過了什麼嗎？

Answer 1

您應該將System.Data.SqlClient作爲值添加到名爲「ProviderName」的新屬性。如下所示： -

<?xml version="1.0" encoding="utf-8" ?> 
<configuration> 
    <connectionStrings> 
    <add name="AddressBook" providerName="System.Data.SqlClient" connectionString="Data Source=MyMachine;Initial Catalog=AddressBook;Integrated Security=True;MultipleActiveResultSets=True;"/> 
    </connectionStrings> 
</configuration> 

Answer 2

當我將我的網站上傳到生產服務器時，發生同樣的錯誤。我的連接字符串有providerName屬性集。問題的cuase是machine.config連接字符串名爲LocalSqlServer，並已經使用了一個角色提供連接字符串：

<roleManager> 
    <providers> 
    <add name="AspNetSqlRoleProvider" connectionStringName="LocalSqlServer" applicationName="/" type="System.Web.Security.SqlRoleProvider, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /> 
    .... 

所以我不得不這樣做登記礦之前清除連接字符串和角色提供：

<connectionStrings> 
    <clear/> 
    <add name="DbEntities" connectionString="..." providerName="System.Data.SqlClient" /> 
    </connectionStrings> 
    ... 
    <roleManager defaultProvider="DefaultRoleProvider" enabled="true"> 
    <providers> 
     <clear/> 
     <add name="DefaultRoleProvider" ... /> 
    </providers> 
    </roleManager>