把参考表和参考字段默认
    下面是两种不同的alv 字段类型的参数
    DATA: lt_fieldcat TYPE slis_t_fieldcat_alv,
    ls_fieldcat TYPE LINE OF slis_t_fieldcat_alv.

    1.   ls_fieldcat-ref_fieldname =  'MENGE' .<br />      ls_fieldcat-ref_tabname = 'EKPO'  .

    DATA: LT_FIELDCAT TYPE lvc_t_fcat,
    ls_fieldcat TYPE lvc_s_fcat. “FIELDCAT结构

    LS_FIELDCAT-REF_TABLE = ‘EKPO’.
    LS_FIELDCAT-REF_FIELD = ‘MENGE’.