实体框架 - 期待'providerInvariantName'参数的非空字符串

Question

好的，这可能与EF无关。我想使用代码优先功能和下面是我写的： -

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()); 

      } 

的上下文类： -

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

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

和连接字符串： -

<?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，数据库名称是“AddressBook”，当我初始化AddressBook对象时发生错误。我看到有人建议将（providerName =“System.Data.SqlClient”）添加到连接字符串中。但它不适用于我的情况。我在这里错过了什么吗？

Answer 1

您应该将System.Data.SqlClient作为值添加到名为“ProviderName”的新属性。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

当我将我的网站上传到生产服务器时，发生同样的错误。我的连接字符串有providerName属性集。问题的cuase是machine.config连接字符串名为LocalSqlServer，并已经使用了一个角色提供连接字符串：

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

所以我不得不这样做登记矿之前清除连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>