string connectionstring1 = "Data Source=127.0.0.1;Initial Catalog=YRB;User ID=sa;Password=sa;Persist Security Info=True";

            string connectionstring2 = "Data Source=.;Initial Catalog=YRB;User ID=sa;Password=sa;Persist Security Info=True";
  
            using (SqlConnection conn = new SqlConnection(connectionstring1))
            {
                conn.Open();
                conn.Close();
            }

            using (SqlConnection conn = new SqlConnection(connectionstring2))
            {
                conn.Open();
                conn.Close();
            }

未处理 System.AccessViolationException
  HResult=-2147467261
  Message=尝试读取或写入受保护的内存。这通常指示其他内存已损坏。
  Source=System.Data
  StackTrace:
       在 SNINativeMethodWrapper.SNIClose(IntPtr pConn)
       在 System.Data.SqlClient.SNIHandle.ReleaseHandle()
       在 System.Runtime.InteropServices.SafeHandle.InternalDispose()
       在 System.Runtime.InteropServices.SafeHandle.Dispose(Boolean disposing)
       在 System.Runtime.InteropServices.SafeHandle.Dispose()
       在 System.Data.SqlClient.TdsParserStateObject.Dispose()
       在 System.Data.SqlClient.TdsParser.Disconnect()
       在 System.Data.SqlClient.SqlInternalConnectionTds.LoginFailure()
       在 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
       在 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData)
       在 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
       在 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
       在 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
       在 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
       在 System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
       在 System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
       在 System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
       在 System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
       在 System.Data.SqlClient.SqlConnection.Open()
       在 ConsoleApplication1.Program.Main(String[] args) 位置 C:\Users\WANGJD\Desktop\ConsoleApplication1\ConsoleApplication1\Program.cs:行号 25
       在 System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       在 System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       在 Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       在 System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Threading.ThreadHelper.ThreadStart()
  InnerException: