Question

我有一个自定义DbContext类，并在运行时从文本文件和DbContext连接字符串中读取连接字符串。例如;

[SuppressMessage("Microsoft.Design", "CA1063:ImplementIDisposableCorrectly")]
[DbConfigurationType(typeof(MySqlEFConfiguration))]
public partial class ASDbContext : IdentityDbContext<ASUser, ASRole, int, ASUserLogin, ASUserRole, ASUserClaim>, IDbContext
{
    private readonly IConnectionStringManager _connectionStringManager;

    public ASDbContext(IDatabaseInitializer<ASDbContext> dbInitializer,
        IDbCommandInterceptor dbCommandInterceptor,
        IConnectionStringManager connectionStringManager) : base() 
    {
        this._connectionStringManager = connectionStringManager;

        if (!_connectionStringManager.CheckIfConnectionStringExists())
        {
            return;
        }
        this.Database.Connection.ConnectionString = _connectionStringManager.ReadConnectionString().;
        System.Data.Entity.Database.SetInitializer(dbInitializer);
        this.Configuration.ProxyCreationEnabled = false;
        DbInterception.Add(dbCommandInterceptor);
    }
     //...                       
}

这适用于Sql Server。但是，它不适用于mysql。以下行抛出异常;

 this.Database.Connection.ConnectionString = _connectionStringManager.ReadConnectionString().ConnectionString;

[ArgumentException：初始化字符串的格式不符合从索引0开始的规范。] System.Data.Common.DbConnectionOptions.GetKeyValuePair（String connectionString，Int32 currentPosition，StringBuilder buffer，Boolean useOdbcRules，String＆amp; keyname，String＆amp; keyvalue）+1739 System.Data.Common.DbConnectionOptions.ParseInternal（Hashtable parsetable，String connectionString，Boolean buildChain，Hashtable synonyms definitions，Boolean firstKey）+191 System.Data.Common.DbConnectionOptions..ctor（String connectionString，Hashtable synonyms definitions，Boolean useOdbcRules）+136 System.Data.Common.DbConnectionStringBuilder.set_ConnectionString（String value）+87 MySql.Data.MySqlClient.MySqlConnectionStringBuilder..ctor（String connStr）+81 MySql.Data.MySqlClient.MySqlConnection.set_ConnectionString（String value）+382 MySql.Data.Entity.MySqlConnectionFactory.CreateConnection（String connectionString）+38 System.Data.Entity.Internal.LazyInternalConnection.Initialize（）+398 System.Data.Entity.Internal.LazyInternalConnection.get_Connection（）+16

我提出的解决方法是将虚拟连接字符串传递给基本DbContext类的构造函数。如;

[SuppressMessage("Microsoft.Design", "CA1063:ImplementIDisposableCorrectly")]
[DbConfigurationType(typeof(MySqlEFConfiguration))]
public partial class ASDbContext : IdentityDbContext<ASUser, ASRole, int, ASUserLogin, ASUserRole, ASUserClaim>, IDbContext
{
    private readonly IConnectionStringManager _connectionStringManager;

    // Passing "S=;" as connection string is a dirty workaround
    public ASDbContext(IDatabaseInitializer<ASDbContext> dbInitializer,
        IDbCommandInterceptor dbCommandInterceptor,
        IConnectionStringManager connectionStringManager) : base("S=;") 
    {
        this._connectionStringManager = connectionStringManager;

        if (!_connectionStringManager.CheckIfConnectionStringExists())
        {
            return;
        }
        this.Database.Connection.ConnectionString = _connectionStringManager.ReadConnectionString().;
        System.Data.Entity.Database.SetInitializer(dbInitializer);
        this.Configuration.ProxyCreationEnabled = false;
        DbInterception.Add(dbCommandInterceptor);
    }
     //...                       
}

虽然，它的工作原理我不喜欢通过虚拟连接字符串来修复问题。还有其他方法可以解决此错误吗？

EF6在运行时使用无参数连接字符串设置连接字符串

0 个答案: