asp.net-mvc 为什么我不能在 DbContextOptionsBuilder 上调用 UseInMemoryDatabase 方法？

Why can't I call the UseInMemoryDatabase method on DbContextOptionsBuilder?

提问by Yusuf Cum

First off, I can't use SQL Lite. Secondly the code below is giving me:

首先，我不能使用 SQL Lite。其次，下面的代码给了我：

Error CS1061 'DbContextOptionsBuilder' does not contain a definition for 'UseInMemoryDatabase' and no extension method 'UseInMemoryDatabase' accepting a first argument of type 'DbContextOptionsBuilder' could be found (are you missing a using directive or an assembly reference?)

错误 CS1061“DbContextOptionsBuilder”不包含“UseInMemoryDatabase”的定义，并且找不到接受“DbContextOptionsBuilder”类型的第一个参数的扩展方法“UseInMemoryDatabase”（您是否缺少 using 指令或程序集引用？）

The code:

编码：

 var options = new DbContextOptionsBuilder<ProductContext>()
                     .UseInMemoryDatabase(Guid.NewGuid().ToString())
                     .Options;
 var context = new ProductContext(options);

Context

语境

using Memory.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;

namespace Memory.Data
{
    public class ProductContext : DbContext
    {
        public ProductContext(DbContextOptions<ProductContext> options) : base(options)
        {

        }
        public DbSet<Category> Categories { get; set; }
        public DbSet<Product> Products { get; set; }
    }
}

My project CSPROJ file

我的项目 CSPROJ 文件

<ItemGroup>
    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.0" />
    <PackageReference Include="Microsoft.AspNetCore" Version="1.1.5" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="1.1.6" />
    <PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="1.1.3" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.5" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.2" />
    <PackageReference Include="Microsoft.VisualStudio.Web.BrowserLink" Version="1.1.3" />
  </ItemGroup>

  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="1.0.3" />
  </ItemGroup>

The exact problem is that the method is just not available. I don't seem to understand why. I require enlightenment on this issue.

确切的问题是该方法不可用。我似乎不明白为什么。我需要对这个问题的启示。

回答by Tetsuya Yamamoto

According to EF Core: Testing with InMemoryreference, you need to add the Microsoft.EntityFrameworkCore.InMemorypackage to use UseInMemoryDatabase()extension method with DbContextOptionsBuilder:

根据EF Core: Testing with InMemory参考，您需要添加Microsoft.EntityFrameworkCore.InMemory包以使用UseInMemoryDatabase()扩展方法DbContextOptionsBuilder：

Install-Package Microsoft.EntityFrameworkCore.InMemory

Afterwards, you can follow example given in "Writing tests" section like this:

之后，您可以按照“编写测试”部分中给出的示例进行操作，如下所示：

var options = new DbContextOptionsBuilder<ProductContext>().UseInMemoryDatabase(databaseName: "database_name").Options;

using (var context = new ProductContext(options))
{
    // add service here
}

回答by Felipe Augusto

You need it to use UseInMemoryDatabase

你需要它来使用 UseInMemoryDatabase

<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="3.0.0" />
</ItemGroup>

回答by Wen Qin Yap

Check in your NuGet Package Manager => Manage Packages for Solution, check all this packages, whether got installedin your solution or not, as below:

检查您的NuGet 包管理器 => 管理解决方案包，检查所有这些包，无论是否已安装在您的解决方案中，如下所示：

1. EntityFrameworkCore
2. Microsoft.EntityFrameworkCore
3. Microsoft.EntityFrameworkCore.InMemory
4. Microsoft.EntityFrameworkCore.Relational
5. Microsoft.EntityFrameworkCore.Sqlite.Core
6. Microsoft.EntityFrameworkCore.SqlServer
7. Microsoft.EntityFrameworkCore.Tools

1. 实体框架核心
2. Microsoft.EntityFrameworkCore
3. Microsoft.EntityFrameworkCore.InMemory
4. Microsoft.EntityFrameworkCore.Relational
5. Microsoft.EntityFrameworkCore.Sqlite.Core
6. Microsoft.EntityFrameworkCore.SqlServer
7. Microsoft.EntityFrameworkCore.Tools

I solved the same issues after check all the above packages been installed.

在检查以上所有软件包都已安装后，我解决了同样的问题。