entity-framework - 添加迁移: The type initializer for 'System.Net.ServicePointManager' threw an exception

Question

我正在尝试在Azure移动服务中进行 Entity Framework 代码优先的迁移。我有在本地运行的项目，并将此新类添加到我的模型中:

using Microsoft.WindowsAzure.Mobile.Service;
using System;

namespace VCollectAPI.DataObjects
{
    public class TagEdit : EntityData
    {
        public string EditedTagId { get; set; }
        public string SourceTagName { get; set; }
        public string ResultingTagName { get; set; }
        public DateTime TimeOfEdit { get; set; }
    }
}

我还将这个属性添加到我的VCollectAPIContext:DbContext类中

public DbSet<TagEdit> TagEdits { get; set; }

并在我的TagDomainManager:EntityDomainManager类中添加一行

if (changedItems.Contains("Name"))
{
    _context.TagEdits.Add(new TagEdit { EditedTagId = current.Id, SourceTagName = current.Name, ResultingTagName = update.Name, TimeOfEdit = DateTime.UtcNow });
    current.Name = update.Name;
}

然后在PMC(软件包管理器控制台)上运行命令
Add-Migration RecordingTagEdits -Verbose
我希望这样做可以使迁移脚手架的架构更新以添加新表。相反，我收到错误消息“System.Net.ServicePointManager的类型初始化程序引发了异常。”

我在做什么错，我该如何解决？

完整的错误跟踪是:

System.TypeInitializationException: The type initializer for 'System.Net.ServicePointManager' threw an exception. ---> System.TypeInitializationException: The type initializer for 'System.Net.ComNetOS' threw an exception. ---> System.Configuration.ConfigurationErrorsException: The element may only appear once in this section. (C:\TFS\HXDMSRC\VisualCollections\Development\VCollectAPI\tmp140.tmp line 16) at System.Configuration.BaseConfigurationRecord.EvaluateOne(String[] keys, SectionInput input, Boolean isTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult) at System.Configuration.BaseConfigurationRecord.Evaluate(FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult, Boolean getLkg, Boolean getRuntimeObject, Object& result, Object& resultRuntimeObject) at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject) at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject) at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject) at System.Configuration.BaseConfigurationRecord.GetSection(String configKey) at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName) at System.Configuration.ConfigurationManager.GetSection(String sectionName) at System.Configuration.PrivilegedConfigurationManager.GetSection(String sectionName) at System.Diagnostics.DiagnosticsConfiguration.Initialize() at System.Diagnostics.DiagnosticsConfiguration.get_Sources() at System.Diagnostics.TraceSource.Initialize() at System.Net.Logging.InitializeLogging() at System.Net.Logging.get_On() at System.Net.ComNetOS..cctor() --- End of inner exception stack trace --- at System.Net.ServicePointManager..cctor() --- End of inner exception stack trace --- at System.Net.ServicePointManager.EnsureStrongCryptoSettingsInitialized() at Microsoft.VisualStudio.Platform.VsAppDomainManager.InitializeNewDomain(AppDomainSetup appDomainInfo) at System.AppDomain.CreateAppDomainManager() at System.AppDomain.Setup(Object arg) at System.AppDomain.nCreateDomain(String friendlyName, AppDomainSetup setup, Evidence providedSecurityInfo, Evidence creatorsSecurityInfo, IntPtr parentSecurityDescriptor) at System.AppDomainManager.CreateDomainHelper(String friendlyName, Evidence securityInfo, AppDomainSetup appDomainInfo) at System.AppDomainManager.CreateDomain(String friendlyName, Evidence securityInfo, AppDomainSetup appDomainInfo) at System.AppDomain.InternalCreateDomain(String friendlyName, Evidence securityInfo, AppDomainSetup info) at System.AppDomain.CreateDomain(String friendlyName, Evidence securityInfo, AppDomainSetup info) at System.Data.Entity.Migrations.Design.ToolingFacade..ctor(String migrationsAssemblyName, String contextAssemblyName, String configurationTypeName, String workingDirectory, String configurationFilePath, String dataDirectory, DbConnectionInfo connectionStringInfo) at System.Data.Entity.Migrations.MigrationsDomainCommand.GetFacade(String configurationTypeName, Boolean useContextWorkingDirectory) at System.Data.Entity.Migrations.AddMigrationCommand.Execute(String name, Boolean force, Boolean ignoreChanges) at System.Data.Entity.Migrations.AddMigrationCommand.<>c__DisplayClass2.<.ctor>b__0() at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command) The type initializer for 'System.Net.ServicePointManager' threw an exception.

Answer 1

检查您的web.config，可能有一些重复的参数。