带有MySQL的EF6.给定的键在字典中不存在 [英] EF6 with MySQL. The given key was not present in the dictionary

问题描述

我有一个使用Code First Entity Framework 6链接到MySQL数据库的Asp.Net MVC 5应用程序.

I have Asp.Net MVC 5 application using Code First Entity Framework 6 linked to MySQL database.

当我第一次创建数据库时，它运行良好.但是，当我对模型进行更改时，请添加迁移. (Update-Database)之后显示错误.

When I created the database first time, it works fine. But when I make a change to the model then add migration. An error shows after (Update-Database).

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:

These are my MySQL Configuration Classes:

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();
            }
        }
    }
}

推荐答案

从错误的第一行开始，

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

MySql.Data.MySqlClient.MySqlConnectionStringBuilder.<>c.<.cctor>b__2_7(MySqlConnectionStringBuilder msb, MySqlConnectionStringOption sender) at MySql.Data.MySqlClient.MySqlConnectionStringBuilder.get_Item(String keyword)

该错误与ConnectionString有关.问题是ConnectionString包含无法读取的密钥.

the error has to do with the ConnectionString. The problem is the ConnectionString contains keys that can't be read.

尝试清理ConnectionString，使其只有

1. 服务器
2. 用户ID
3. 密码
4. 数据库

在我的情况下，ConnectionString有一个额外的键integrated security.删除此内容后，Update-Database开始正常工作.但是，根据您的情况，这可能是(也可能不是)导致错误的关键.

In my case, the ConnectionString had an extra key integrated security. When this was removed Update-Database started working fine. Depending on your case however, this might and might not be the key that caused the error.

因此，再次提出我建议并保证的解决方案，通过ConnectionString并将其简化，使其仅包含上述4个键.

So again my proposed and guaranteed solution, go through ConnectionString and simplify it so that it contains only the 4 keys mentioned above.

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