Powershell无法在VS 2013 Package Manager控制台中找到其dll或依赖项

Question

I'm using VS Express 2013 .Net 4.5. I'm designing in MVC5 and EF6 with MS SQLServer LocalDB in an Oracle VirtualBox Windows 7 64bit client.

I am trying to apply SQL Server LocalDb migrations with the command:

PM> Enable-Migrations -ContextTypeName SGHWA_MVC.Models.Context

This always fails.

My limited web knowledge is with Web Forms so I am completely new to MVC and EF. Also I have never used PMC and Powershell. I have searched for solutions but have not found questions similar to this error that Package Manager Console produces.

First there is a warning:-

Cannot determine a valid start-up project. Using project 'SGHWA_MVC' instead. Your configuration file and working directory may not be set as expected. Use the -StartUpProjectName parameter to set one explicitly. Use the -Verbose switch for more information.

PCM drop-down box shows the Default project correctly as SGHWA_MVC. The solution property pages show this one project as the start-up project.

I went to http://docs.nuget.org/docs/reference/package-manager-console-powershell-reference but could not see the -StartUpProjectName parameter mentioned. I'm not sure to which command this parameter applies.

Then the first error appears:-

Exception calling "LoadFrom" with "1" argument(s): "Could not load file or assembly 'file://\\W7O2007\\Users\\Admin\\Documents\\Visual Studio 2013\\Projects\\SGHWA_MVC\\packages\\EntityFramework.6.1.0\\tools\\EntityFramework.PowerShell.Utility.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)"At \\W7O2007\\Users\\Admin\\Documents\\Visual Studio 2013\\Projects\\SGHWA_MVC\\packages\\EntityFramework.6.1.0\\tools\\EntityFramework.psm1:780 char:62
+ $utilityAssembly = [System.Reflection.Assembly]::LoadFrom <<<< ((Join-Path $ToolsPath EntityFramework.PowerShell.Utility.dll))
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : DotNetMethodException

It suggests the file is not there to be loaded but it does exist on the PC at the path shown. I suspect it is the Join-Path that fails but am unsure how to test this.

The packages.config files has a line:-

(leading < removed) package id="Powershell.Deployment" version="1.1.0.0" targetFramework="net45" />

My research shows it could be permissions, remote access, that the Project Build should have Generate Serialization Assembly as 'On', 'Off' or 'Auto' or even NuGet packages that cause this but I cannot determine if it is a PMC, NuGet, Powershell or Windows problem.

Two more error messages appear relating to similar problems in EntityFramework.psm1 and seem to be related to this first problem.

Please can anyone advise the likely cause and guide me through what/how to test and solve this?

Answer 1

I realize this is an old thread, but I just ran into this problem using a newly-installed copy of Microsoft Visual Studio 2015 Enterprise with Update 1.

My solution was to delete this folder:

C:\Users\\(my user ID)\\.nuget\packages\EntityFramework\6.1.3

and allow it to be regenerated the next time the Entity Framework is added to a project. Originally, the PowerShell DLL's were missing from this folder. Strange.

Answer 2

Your question has several parts.

First, you cannot find the documentation, and you have it at your fingertips:

Update-Database -?

Then, you can read at the bottom of this help:

TO see the examples, type: "get-help Update-Database -examples".
For more information, type: "get-help Update-Database -detailed".
For technical information, type: "get-help Update-Database -full".

Second, -StartupProjectName is required to find the configuration file that has the required connection string (you also specify the connection directly using another options) NOTE: This has nothing to do with the solution's startup project

And, if having this clear doesn't solve the problem, try uninstalling and reinstalling the EntityFramework package (in case something went wrong). Take into account that, if you have several projects, it's possible that you need to do this for all the affected projects. You can do this more easily using the Manage Nuget Packages for Solution... menu option.

Edit

(Added to help choose the right Default project in Package Manager Console or specify -ProjectName ).

I forgot to answer the most important part of the question: for Migrations commands to work, it's necessary to run them on a project that references the EF assemblies. This solves the missing assembly problem.

In this case it's clear that the chosen StartUpProject, which is the Web App have the connection strings, but doesn't have a reference to EF. That's why running the command fails. And most probably the command is being run with this as the default project in the console.

To solve this, you need to run Migrations within a project which has references to EF, and it will work flawlessly: choose that project in the drop down list named "Default project" on the top bar of the Package Manager Console.

This can also be done by specifying the -ProjectName option, which must point to the project containing the Migration configuration class, and thus, have also the reference to EF. NOTE: you must also sepcify the -ConfigurationTypeName param if you have several migrations for several contexts, as supported from EF 6 .