带有 MySQL 的 EF6。 字典中不存在给定的键

Question

我有一个使用代码优先实体框架 6 链接到 MySQL 数据库的 Asp.Net MVC 5 应用程序。

当我第一次创建数据库时，它工作正常。 但是当我对模型进行更改时，然后添加迁移。 在（更新数据库）之后显示错误。

这是错误：

        PM> Update-Database 
        System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
           at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
           at MySql.Data.MySqlClient.MySqlConnectionStringBuilder.<>c.<.cctor>b__2_7(MySqlConnectionStringBuilder msb, MySqlConnectionStringOption sender)
           at MySql.Data.MySqlClient.MySqlConnectionStringBuilder.get_Item(String keyword)
           at MySql.Data.MySqlClient.MySqlConnectionStringBuilder.GetConnectionString(Boolean includePass)
           at MySql.Data.MySqlClient.MySqlConnection.get_ConnectionString()
           at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<GetConnectionString>b__12(DbConnection t, DbConnectionInterceptionContext`1 c)
           at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget, TInterceptionContext, TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
           at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.GetConnectionString(DbConnection connection, DbInterceptionContext interceptionContext)
           at System.Data.Entity.Internal.InternalConnection.GetStoreConnectionString(DbConnection connection)
           at System.Data.Entity.Internal.InternalConnection.OnConnectionInitialized()
           at System.Data.Entity.Internal.EagerInternalConnection..ctor(DbContext context, DbConnection existingConnection, Boolean connectionOwned)
           at System.Data.Entity.DbContext..ctor(DbConnection existingConnection, Boolean contextOwnsConnection)
           at System.Data.Entity.Migrations.History.HistoryContext..ctor(DbConnection existingConnection, String defaultSchema)
           at MySql.Data.Entity.MySqlHistoryContext..ctor(DbConnection existingConnection, String defaultSchema)
           at code_first_mysql.Migrations.Configuration.<>c.<.ctor>b__0_0(DbConnection conn, String schema) in C:\Users\User\Documents\Tree\New Backend\code first mysql\Migrations\Configuration.cs:line 16
           at System.Data.Entity.Migrations.History.HistoryRepository.CreateContext(DbConnection connection, String schema)
           at System.Data.Entity.Migrations.History.HistoryRepository.<GetUpgradeOperations>d__16.MoveNext()
           at System.Linq.Enumerable.Any[TSource](IEnumerable`1 source)
           at System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration)
           at System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClassc.<Update>b__b()
           at System.Data.Entity.Migrations.Infrastructure.MigratorScriptingDecorator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
           at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
           at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
           at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
           at System.Data.Entity.Migrations.Infrastructure.MigratorScriptingDecorator.ScriptUpdate(String sourceMigration, String targetMigration)
           at System.Data.Entity.Migrations.Design.ToolingFacade.ScriptUpdateRunner.Run()
           at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
           at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
           at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
           at System.Data.Entity.Migrations.Design.ToolingFacade.ScriptUpdate(String sourceMigration, String targetMigration, Boolean force)
           at System.Data.Entity.Migrations.UpdateDatabaseCommand.<>c__DisplayClass2.<.ctor>b__0()
           at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
        The given key was not present in the dictionary.

这些是我的 MySQL 配置类：

internal sealed class Configuration : DbMigrationsConfiguration<ApplicationDbContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
        SetSqlGenerator("MySql.Data.MySqlClient", new MySqlMigrationSqlGenerator());
        SetHistoryContextFactory("MySql.Data.MySqlClient", (conn, schema) => new MySqlHistoryContext(conn, schema));
        CodeGenerator = new MySqlMigrationCodeGenerator();
    }

    protected override void Seed(ApplicationDbContext context)
    {}
}


public class MySqlConfiguration: DbConfiguration
{

    public MySqlConfiguration()
    {
        SetHistoryContext("MySql.Data.MySqlClient", (conn, schema) => new MySqlHistoryContext(conn, schema));
    }

}



public class MySqlHistoryContext : HistoryContext 
{
    public MySqlHistoryContext(DbConnection existingConnection, string defaultSchema) : base(existingConnection, defaultSchema)
    {
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<HistoryRow>().Property(h => h.MigrationId).HasMaxLength(100).IsRequired();
        modelBuilder.Entity<HistoryRow>().Property(h => h.ContextKey).HasMaxLength(200).IsRequired();
    }
}

 public class MySqlInitializer : IDatabaseInitializer<ApplicationDbContext>
{

    public void InitializeDatabase(ApplicationDbContext context)
    {
        if (!context.Database.Exists())
        {
            // if database did not exist before - create it
            context.Database.Create();
        }
        else
        {
            // query to check if MigrationHistory table is present in the database 
            var migrationHistoryTableExists = ((IObjectContextAdapter)context).ObjectContext.ExecuteStoreQuery<int>(
            string.Format(
              "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = '{0}' AND table_name = '__MigrationHistory'", "mydb"));

            // if MigrationHistory table is not there (which is the case first time we run) - create it
            if (migrationHistoryTableExists.FirstOrDefault() == 0)
            {
                context.Database.Delete();
                context.Database.Create();
            }
        }
    }
}

Answer 1

正如你从错误的第一行看到的，

MySql.Data.MySqlClient.MySqlConnectionStringBuilder.<>c.<.cctor>b__2_7(MySqlConnectionStringBuilder msb, MySqlConnectionStringOption sender) 在 MySql.Data.MySqlClient.MySqlConnectionStringBuilder.get_Item(String 关键字)

该错误与ConnectionString 。 问题是ConnectionString包含无法读取的键。

尝试清理ConnectionString以便它只有

1. 服务器
2. 用户名
3. 密码
4. 数据库

就我而言， ConnectionString有一个额外的密钥integrated security 。 当它被删除时， Update-Database开始工作正常。 但是，根据您的情况，这可能是也可能不是导致错误的关键。

因此，我再次提出并保证解决方案，通过ConnectionString并对其进行简化，使其仅包含上述 4 个键。

Answer 2

Bug 75172这是一个在 6.9.4 版本中报告的错误，但我在 6.9.11 中对其进行了审查。

Answer 3

不要应用最新的mysql工具

1. 关闭 Visual Studio 2017

2. 卸载 mysql-for-visualstudio 2.0.5 然后，安装 mysql-for-visualstudio 1.2.8

3. 卸载 mysql-connector-net-8.0.17 然后，安装 mysql-connector-net-6.9.10。 在%Program Files (x86)%\\MySQL\\MySQL Connector Net 6.9.10\\Assemblies\\v4.5 中找到mysql.data.dll、MySql.Data.Entity.EF6.dll 添加到参考

4. 在引用中打开 nuget，将 EntityFramework 6 降级为 EntityFramework 5

Answer 4

这对我有用：关闭你的视觉工作室并

1. 转到此文件夹 C:\\Users[youruser]\\AppData\\Roaming\\Microsoft\\VisualStudio\\16.0_befcda98\\ServerExplorer

2. 然后删除文件 DefaultView.SEView

3. 打开您的视觉工作室并重试。