学习 ef 6 的碰到的一些问题

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环境 : vs2010 / nuget 2.8 / ef6.1.3 / 数据库环境为 windows sqlserver 2008 标准版

在安装NuGet时，遇到了一个错误

Error: The Package Manager Console requires PowerShell 2.0 runtime, which is not detected on this machine.
Please install the PowerShell 2.0 from http://support.microsoft.com/kb/968929 and restart Visual Studio.

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Windows Management Framework Core Setup Error
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Setup cannot continue because your system contains an incompatible version of PowerShell or WinRM. Please uninstall PowerShell and WinRM and run setup again.
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确定
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解决办法

解决方案：卸载PowerShell 1.0 注意显示更新要打勾

官网示例

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data.Entity;namespace StudyProject{   #region CodeFirst   class Program   {      static void Main(string[] args)      {         #region  read and write          using (var db = new BloggingContext())         {            // Create and save a new Blog             Console.Write("Enter a name for a new Blog: ");            var name = Console.ReadLine();            var blog = new Blog { Name = name };            db.Blogs.Add(blog);            db.SaveChanges();            // Display all Blogs from the database             var query = from b in db.Blogs                        orderby b.Name                        select b;            Console.WriteLine("All blogs in the database:");            foreach (var item in query)            {               Console.WriteLine(item.Name);            }            Console.WriteLine("Press any key to exit...");            Console.ReadKey();         }          #endregion      }   }   public class Blog   {      public int BlogId { get; set; }      public string Name { get; set; }      public virtual List<Post> Posts { get; set; }   }   public class Post   {      public int PostId { get; set; }      public string Title { get; set; }      public string Content { get; set; }      public int BlogId { get; set; }      public virtual Blog Blog { get; set; }   }   public class BloggingContext : DbContext   {      public DbSet<Blog> Blogs { get; set; }      public DbSet<Post> Posts { get; set; }   }    #endregion   }

运行出现如下错误:

在与 SQL Server 建立连接时出现与网络相关的或特定于实例的错误。未找到或无法访问服务器。请验证实例名称是否正确并且 SQL Server 已配置为允许远程连接。 (provider:

SQL Network Interfaces, error: 26 - 定位指定的服务器/实例时出错)

解决方案:

   public class BloggingContext : DbContext   {      public BloggingContext() : base("BloggingCompactDatabase") {  }      public DbSet<Blog> Blogs { get; set; }      public DbSet<Post> Posts { get; set; }   }

app.config 更改为如下

<?xml version="1.0" encoding="utf-8"?><configuration>  <configSections>    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />  </configSections>  <entityFramework>    <!--<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">      <parameters>             </parameters>    </defaultConnectionFactory>-->    <providers>      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />    </providers>  </entityFramework>  <connectionStrings>       <add name="BloggingCompactDatabase"             providerName="System.Data.SqlClient"         connectionString="Data Source=localhost;Initial Catalog=ef6;Persist Security Info=false;User ID=sa; Password=sa.123" />  </connectionStrings>   </configuration>

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