无法加载文件或程序集工具\EntityFramework .PowerShell.Utility.dll'

Question

尝试从包管理器控制台安装 Entity Framework 6.1.3 时。我得到以下输出。

Install-Package EntityFramework 
Attempting to gather dependency information for package 'EntityFramework.6.1.3' with respect to project 'OnlineShop', targeting '.NETFramework,Version=v4.6.1'
Attempting to resolve dependencies for package 'EntityFramework.6.1.3' with DependencyBehavior 'Lowest'
Resolving actions to install package 'EntityFramework.6.1.3'
Resolved actions to install package 'EntityFramework.6.1.3'
Adding package 'EntityFramework.6.1.3' to folder 'D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages'
Added package 'EntityFramework.6.1.3' to folder 'D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages'
Added package 'EntityFramework.6.1.3' to 'packages.config'
Executing script file 'D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\EntityFramework.6.1.3\tools\install.ps1'
Exception calling "LoadFrom" with "1" argument(s): "Could not load file or asse
mbly 'file:///D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop
\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.Utility.dll' o
r one of its dependencies. The system cannot find the file specified."
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:780 char:5
+     $utilityAssembly = [System.Reflection.Assembly]::LoadFrom((Join-Path $Too
lsP ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException

You cannot call a method on a null-valued expression.
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:781 char:5
+     $dispatcher = $utilityAssembly.CreateInstance(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

Exception calling "CreateInstanceFrom" with "8" argument(s): "Could not load fi
le or assembly 'file:///D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\
OnlineShop\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.dll'
 or one of its dependencies. The system cannot find the file specified."
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:809 char:5
+     $domain.CreateInstanceFrom(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException

Exception calling "LoadFrom" with "1" argument(s): "Could not load file or asse
mbly 'file:///D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop
\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.Utility.dll' o
r one of its dependencies. The system cannot find the file specified."
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:780 char:5
+     $utilityAssembly = [System.Reflection.Assembly]::LoadFrom((Join-Path $Too
lsP ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException

You cannot call a method on a null-valued expression.
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:781 char:5
+     $dispatcher = $utilityAssembly.CreateInstance(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

Exception calling "CreateInstanceFrom" with "8" argument(s): "Could not load fi
le or assembly 'file:///D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\
OnlineShop\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.dll'
 or one of its dependencies. The system cannot find the file specified."
At D:\Leva\Work\Informatika\CSharp\My OPENSOURCE projects\OnlineShop\packages\E
ntityFramework.6.1.3\tools\EntityFramework.psm1:809 char:5
+     $domain.CreateInstanceFrom(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException


Type 'get-help EntityFramework' to see all available Entity Framework commands.
Successfully installed 'EntityFramework 6.1.3' to OnlineShop

如您所见，存在异常。但毕竟，Entity Framework 6.1.3 已成功添加到项目中，尽管存在异常。此外，当我添加对 System.Data.Entity 的引用并尝试在代码中使用它时。我无法连接到 System.Data.Entity 命名空间并使用此命名空间的库。它是否以某种方式连接到上述异常，以及如何解决这个问题？

Answer 1

使用 EntityFramework6\Add-Migration 命令，微软已经更改了 cmdmidlet 的名称

Answer 2

我通过将 Entity Framework 6.1.3 降级到 Entity Framework 6.1.2 解决了这个问题。可能是上一个版本的错误。

Answer 3

我刚刚在 .NET Framework 4.5 项目中的 Visual Studio 2019 (v16.5.4) 中使用 EntityFramework 6.4.0 时遇到了同样的问题。

PM> Enable-Migrations
Exception calling "LoadFrom" with "1" argument(s): "Could not load file or assembly 'file:///C:\Users\Administrator\source\repos\InfrastructureManager\packages\EntityFramework.6.4.0\tools\EntityFramework.PowerShell.Utility.dll' or one of its dependencies. The system cannot find the file specified."
At C:\Users\Administrator\source\repos\InfrastructureManager\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:780 char:5
+     $utilityAssembly = [System.Reflection.Assembly]::LoadFrom((Join-P ...
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException
 
You cannot call a method on a null-valued expression.
At C:\Users\Administrator\source\repos\InfrastructureManager\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:781 char:5
+     $dispatcher = $utilityAssembly.CreateInstance(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
 
Exception calling "CreateInstanceFrom" with "8" argument(s): "Could not load file or assembly 'file:///C:\Users\Administrator\source\repos\InfrastructureManager\packages\EntityFramework.6.4.0\tools\EntityFramework.PowerShell.dll' or one of its dependencies. The system cannot find the file specified."
At C:\Users\Administrator\source\repos\InfrastructureManager\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:809 char:5
+     $domain.CreateInstanceFrom(
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FileNotFoundException
 

解决方案是（包管理器控制台）：

Uninstall-Package EntityFramework -Force
Install-Package EntityFramework -Version 6.1.2
Enable-Migrations

Answer 4

从项目中卸载EntityFramework ，然后重新启动项目并重新安装EntityFramework

Answer 5

对我来说，这是通过将解决方案中的所有 EF 项目升级到相同的 EF 版本来解决的。我不同意微软的产品很糟糕。我喜欢 VS Ide 环境。没有什么可以与之相比。