c# - 启用迁移时出错

Question

我是 EF 的新手，当我尝试在 PMC 控制台中运行 Enable-Migrations 时出现错误: 使用“1”个参数调用“LoadFrom”时出现异常:

 "Could not load file or assembly 'file:///...\pa
ckages\EntityFramework.6.0.1\tools\EntityFramework.PowerShell.Utility.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)"
At ...\packages\EntityFramework.6.1.1\tools\EntityFramework.psm1:780 char:62
+     $utilityAssembly = [System.Reflection.Assembly]::LoadFrom <<<< ((Join-Path $ToolsPath EntityFramework.PowerShell.Utility.dll))
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException



You cannot call a method on a null-valued expression.
At ...\packages\EntityFramework.6.1.1\tools\EntityFramework.psm1:781 char:50
+     $dispatcher = $utilityAssembly.CreateInstance <<<< (
    + CategoryInfo          : InvalidOperation: (CreateInstance:String) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

Exception calling "CreateInstanceFrom" with "8" argument(s): "Could not load file or assembly 'file:///...\packages\EntityFramework.6.0.1\tools\EntityFramework.PowerShell.dll' or one of its dependencies. Operation is no t supported. (Exception from HRESULT: 0x80131515)"
At ...\packages\EntityFramework.6.1.1\tools\EntityFramework.psm1:809 char:31
+     $domain.CreateInstanceFrom <<<< (
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException

Answer 1

我刚刚在我同事的一台机器上遇到了这个问题。解决方案是:

1. 卸载 EF NuGet 包
2. 从 Web.Config/App.Config 文件中手动删除 Entity Framework 部分
3. 关闭 Visual Studio
4. 在 Visual Studio 中重新打开解决方案
5. 重新安装 EF NuGet 包