abap - SELECTION-SCREEN 的编译失败

Question

以下 ABAP 代码块有什么问题？程序的编译确实会导致错误，但没有显示详细信息。请建议更改代码以使其正常工作

REPORT  ZSELECTIONSCREENCOMMENTS.
SELECTION-SCREEN BEGIN OF BLOCK B1 WITH FRAME TITLE TIT1.
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN POSITION 20.
PARAMETERS: P_MATNR LIKE MARA-MATNR, P_ERSDA LIKE MARA-ERSDA, P_ERNAM LIKE MARA-ERNAM.
SELECTION-SCREEN COMMENT 1(12) COM1 FOR FIELD P_MATNR.
SELECTION-SCREEN COMMENT 1(12) COM2 FOR FIELD P_ERSDA.
SELECTION-SCREEN COMMENT 1(12) COM3 FOR FIELD P_ERNAM.
SELECTION-SCREEN END OF LINE.
SELECTION-SCREEN END OF BLOCK B1.
LOAD-OF-PROGRAM.
TIT1 = 'Selection-Criteria'.
COM1 = 'Material No'.
COM2 = 'ERSDA'.
COM3 = 'ERNAM'.

Answer 1

您正在尝试将多个注释放置在单行（BEGIN OF LINE...END OF LINE块）内的同一位置，并且您正在向该单行添加多个参数而不指定位置。