Oracle 数据库 18c – ORA-12541: TNS:no listener

我已经在我的本地机器上安装了 Oracle 18c，并且我创建了一个用户名

USER_NAME := c##scott
Passkey : oracle

当我曾经使用 cmd 连接到该用户时。正在填充以下错误。

Command: sqlplus c##scott/oracle@agndev

ERROR:
ORA-12541: TNS:no listener

检查侦听器错误后，我重新检查了侦听器文件

监听文件：

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = D:\ora_base)
      (PROGRAM = extproc)
      (ENVS = "EXTPROC_DLLS=ONLY:D:\ora_base\bin\oraclr18.dll")
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = AGNDEV))
    )
  )

Tnsnames.ora 文件：

# tnsnames.ora Network Configuration File: D:\ora_base\NETWORK\ADMIN\tnsnames.ora
# Generated by Oracle configuration tools.

    ORACLR_CONNECTION_DATA =
      (DESCRIPTION =
        (ADDRESS_LIST =
          (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
        )
        (CONNECT_DATA =
          (SID = CLRExtProc)
          (PRESENTATION = RO)
        )
      )

    AGNDEV =
      (DESCRIPTION =
        (ADDRESS_LIST =
          (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
        )
        (CONNECT_DATA =
          (SERVICE_NAME = AGNDEV)
        )

  )

我是 18c 的新手，谁能说出这个错误的解决方案。

谢谢你。