C#通过连接字符串检索正确的DbConnection对象

Question

我有一个连接字符串传递给一个函数,我需要基于这个字符串创建一个基于DbConnection的对象(即SQLConnection,OracleConnection,OLEDbConnection等).

是否有任何内置功能可以执行此操作,或任何第三方库可以提供帮助.我们不一定要构建这个连接字符串,所以我们不能依赖于写入字符串的格式来确定它的类型,我宁愿不必编写可能的连接字符串的所有组合和排列

Answer 1

   DbConnection GetConnection(string connStr)
    { string providerName = null;
      var    csb = new DbConnectionStringBuilder{ConnectionString=connStr};

      if (csb.ContainsKey("provider")) 
       { providerName = csb["provider"].ToString();
       }          
      else
       { var css = ConfigurationManager
                           .ConnectionStrings
                           .Cast<ConnectionStringSettings>()
                           .FirstOrDefault(x=>x.ConnectionString==connStr);
         if (css != null) providerName = css.ProviderName;
       }

      if (providerName != null) 
       { var providerExists =  DbProviderFactories
                                     .GetFactoryClasses()
                                     .Rows.Cast<DataRow>()
                                     .Any(r=>r[2].Equals(providerName));
         if (providerExists) 
          { var factory = DbProviderFactories.GetFactory(providerName);
            var dbConnection = factory.CreateConnection();

            dbConnection.ConnectionString = connStr;
            return dbConnection;
          }
       }

      return null;
   }

Answer 2

如果您使用的是框架2.0或更高版本,并且可以让它们使用驱动程序类传递第二个字符串,则可以使用dbProviderFactory类为您加载驱动程序.

DbProviderFactory dbProviderFactory = DbProviderFactories.GetFactory(myDriverClass);
DbConnection dbConnection = dbProviderFactory.CreateConnection();
dbConnection.ConnectionString = myConnectionString;

这是工厂类的MSDN链接:http: //msdn.microsoft.com/en-us/library/wda6c36e.aspx