找不到类型或命名空间名称“DbContext" [英] The type or namespace name 'DbContext' could not be found
问题描述
我对 ASP.NET MVC (3) 非常陌生,并且很难解决 Visual Studio 中的构建错误:
找不到类型或命名空间名称DbContext"(您是否缺少 using 指令或程序集引用?)
使用系统;使用 System.Collections.Generic;使用 System.Linq;使用 System.Web;使用 System.ComponentModel.DataAnnotations;使用 System.Data.Entity;命名空间 MyProjectName.Models{公共类 MachineModel{//名称[必需的][Display(Name = "Nom de la machine")]公共字符串名称 { 获取;放;}//IP[必需的][RegularExpression(@"(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)",ErrorMessage = "Donnez une adresse IPv4 valide.")][Display(Name = "Adresse IP de la machine")]公共字符串 IP { 获取;放;}}公共类 MachineDbContext : DbContext{公共 DbSet机器{得到;放;}}}
我得到的两个错误是:
- 类型或命名空间名称找不到DbContext"(是您缺少 using 指令或程序集参考?)
- 类型或命名空间名称DbSet"找不到(你是缺少 using 指令或汇编参考?)
我错过了什么?
我遇到了同样的问题.事实证明,您需要 EntityFramework.dll 引用(而不是 System.Data.Entity).
我刚刚从 MvcMusicStore 应用程序中提取了它,您可以从以下位置下载:http://mvcmusicstore.codeplex.com/>
这也是如何在 MVC 中使用实体框架代码优先的有用示例.
I am VERY new to ASP.NET MVC (3) and am having a hard time resolving a build error in Visual Studio:
The type or namespace name 'DbContext' could not be found (are you missing a using directive or an assembly reference?)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.Data.Entity;
namespace MyProjectName.Models
{
public class MachineModel
{
// name
[Required]
[Display(Name = "Nom de la machine")]
public string Name { get; set; }
// IP
[Required]
[RegularExpression(@"(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)",
ErrorMessage = "Donnez une adresse IPv4 valide.")]
[Display(Name = "Adresse IP de la machine")]
public string IP { get; set; }
}
public class MachineDbContext : DbContext
{
public DbSet<MachineModel> Machines{ get; set; }
}
}
The two errors I am getting are:
- The type or namespace name 'DbContext' could not be found (are you missing a using directive or an assembly reference?)
- The type or namespace name 'DbSet' could not be found (are you missing a using directive or an assembly reference?)
What am I missing?
I had the same issue. Turns out, you need the EntityFramework.dll reference (and not System.Data.Entity).
I just pulled it from the MvcMusicStore application which you can download from: http://mvcmusicstore.codeplex.com/
It's also a useful example of how to use entity framework code-first with MVC.
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