动态内表的创建和使用主要有以下几点：
1.动态内表的创建，首先要定义动态结构，然后再根据定义的动态结构利用系统一个标准的method：”cl_alv_table_create=>create_dynamic_table“生成动态内表。
2.动态内表的赋值，遍历动态结构，获取指定的字段，然后给指定的字段赋值。
3.动态内表的读取显示，与赋值相似，遍历动态结构，获取指定的字段，然后读取对应字段的值。
具体实现方法如下所示：
定义：
FIELD-SYMBOLS:<dyn_table> TYPE STANDARD TABLE,
<dyn_wa> TYPE ANY,
<dyn_field> TYPE ANY.
DATA: dy_table TYPE REF TO data,
dy_line TYPE REF TO data,
it_structure TYPE lvc_t_fcat,
wa_structure TYPE lvc_s_fcat.
实现步骤：
1.PERFORM create_structure." 定义内表的结构
FORM create_structure.
CLEAR it_structure.
DATA:l_pos TYPE i.
l_pos = 5.
wa_structure-fieldname = 'MANUFACTURER'." 第一列名
wa_structure-col_pos = 1. " 表示第1列 ---
wa_structure-ref_table = 'PLAF'. ”字段参照的内表名字
wa_structure-ref_field = 'FLIEF'. “字段参照的字段名字
APPEND wa_structure TO it_structure.
wa_structure-fieldname = 'NAME'. " 第二 列名
wa_structure-col_pos = 2. " 表示第2列 ---
wa_structure-ref_table = 'lfa1'.
wa_structure-ref_field = 'NAME1'.
APPEND wa_structure TO it_structure.
wa_structure-fieldname = 'DESCRIPTION'. " 第三列名
wa_structure-col_pos = 3. " 表示第3列 ---
wa_structure-ref_table = 'MAKT'.
wa_structure-ref_field = 'MAKTX'.
APPEND wa_structure TO it_structure.
wa_structure-fieldname = 'MM#'.
wa_structure-col_pos = 4.
wa_structure-ref_table = 'MAKT'.
wa_structure-ref_field = 'MATNR'.
APPEND wa_structure TO it_structure.
"it_month是根据选择屏幕的起始时间和结束时间得到的两个日期之间的月份，以下遍历所得到的月份并写入结构。
LOOP AT it_month INTO wa_month.
wa_structure-fieldname = wa_month-pedtr.
wa_structure-col_pos = l_pos.
wa_structure-inttype = 'P'.
"wa_structure-intlen = 7.
APPEND wa_structure TO it_structure.
l_pos = l_pos + 1.
ENDLOOP.
ENDFORM. "CREATE_STRUCTURE
2.PERFORM create_dynamic_table." 按照定义的内表结构，产生一个内表
利用系统 的一个标准方法根据结构生成动态内表
FORM create_dynamic_table.
CALL METHOD cl_alv_table_create=>create_dynamic_table
EXPORTING
it_fieldcatalog = it_structure
IMPORTING
ep_table = dy_table.
ASSIGN dy_table->* TO <dyn_table>.
"表类型指针 <dyn_table> 指向 数据对象的内容.
ENDFORM. " create_dynamic_table
3.PERFORM write_data_to_dyntable." 向动态内表中写数
FORM write_data_to_dyntable .
DATA:wa_new_line TYPE REF TO data.
DATA:l_index2 TYPE i.
CREATE DATA wa_new_line LIKE LINE OF <dyn_table>.
*建立一个与动态内表结构相同的数据对象，且数据对象为是一个结构
ASSIGN wa_new_line->* TO <dyn_wa>." 用<dyn_wa>指针指向该结构
SORT it_plaf_out BY flief matnr .
LOOP AT it_plaf_out INTO wa_plaf_out.
l_index2 = sy-tabix.
LOOP AT it_structure INTO wa_structure.
READ TABLE it_plaf_out INTO wa_plaf_out INDEX l_index2.
IF wa_structure-fieldname = 'MANUFACTURER'.
ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
" 用指针<DYN_FIELD>指向工作区<DYN_WA>中的一个字段，字段名为WA_STRUCTURE-FIELDNAME.
<dyn_field> = wa_plaf_out-flief. ”给指针指向的字段赋值
ELSEIF wa_structure-fieldname = 'NAME'.
ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
<dyn_field> = wa_plaf_out-name1.
ELSEIF wa_structure-fieldname = 'DESCRIPTION'.
ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
<dyn_field> = wa_plaf_out-maktx.
ELSEIF wa_structure-fieldname = 'MM#'.
ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
<dyn_field> = wa_plaf_out-matnr.
ELSEIF wa_structure-fieldname = wa_plaf_out-pedtr.
ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
<dyn_field> = wa_plaf_out-gsmng.
ENDIF.
ENDLOOP.
AT END OF matnr.
APPEND <dyn_wa> TO <dyn_table>."将所得到的工作区的值写入内表
CLEAR <dyn_wa>.
ENDAT.
ENDLOOP.
ENDFORM. "WRITE_DATA_TO_DYNTABLE
PERFORM output_dyntable_data." 从动态内表中取数，并写到屏幕
* LOOP AT it_structure INTO wa_structure.
* WRITE: wa_structure-fieldname(5).
* ENDLOOP.
* LOOP AT <dyn_table> INTO <dyn_wa>.
* WRITE: / .
* LOOP AT it_structure INTO wa_structure.
* ASSIGN COMPONENT wa_structure-fieldname OF STRUCTURE <dyn_wa>
* TO <dyn_field>.
**用指针<DYN_FIELD>指向工作区<DYN_WA>中的一个字段，字段名为WA_STRUCTURE-FIELDNAME.
* WRITE : <dyn_field>.
* ENDLOOP.
* ENDLOOP.
若要通过ALV显示的话。
利用wa_alv_field定义对应结构的ALV，然后即可显示
g_repid = sy-repid.
wa_layout-colwidth_optimize = 'X'.
wa_layout-zebra = 'X'.
" lt_layout-box_fieldname = 'SEL'.
DATA:l_colpos TYPE i.
l_colpos = 5.
" lit_fcat
wa_alv_field-col_pos = 1.
wa_alv_field-fieldname = 'MANUFACTURER'.
wa_alv_field-seltext_m = 'MANUFACTURER'.
wa_alv_field-no_zero = 'X'.
APPEND wa_alv_field TO lit_fcat.
wa_alv_field-col_pos = 2.
wa_alv_field-fieldname = 'NAME'.
wa_alv_field-seltext_m = 'NAME'.
APPEND wa_alv_field TO lit_fcat.
wa_alv_field-col_pos = 3.
wa_alv_field-fieldname = 'DESCRIPTION'.
wa_alv_field-seltext_m = 'DESCRIPTION'.
APPEND wa_alv_field TO lit_fcat.
wa_alv_field-col_pos = 4.
wa_alv_field-fieldname = 'MM#'.
wa_alv_field-seltext_m = 'MM#'.
wa_alv_field-no_zero = 'X'.
APPEND wa_alv_field TO lit_fcat.
LOOP AT it_month INTO wa_month.
wa_alv_field-col_pos = l_colpos.
wa_alv_field-fieldname = wa_month-pedtr.
wa_alv_field-seltext_m = wa_month-pedtr.
APPEND wa_alv_field TO lit_fcat.
l_colpos = l_colpos + 1.
ENDLOOP.
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
关键技巧:
1， 创建动态内表：
a, 动态内表的结构的定义.
动态内表表结构的定义必须使用表结构与 table type: lvc_t_fcat一样的内表.
一般情况下，我们都内表的所有列定义成字符型.
b, 根据表结构生成内表.
系统提供了一个标准的method来产生动态表，使用方法如下:
2， 动态内表的赋值：
a, 获取指定的字段
b, 给指定的字段赋值
3， 读取动态内表的值：
a, 获取指定的字段
b, 读取指定的字段值
*&---------------------------------------------------------------------*
*& Report YDYN_TEST
*&---------------------------------------------------------------------*
REPORT YDYN_TEST.
FIELD-SYMBOLS:<DYN_TABLE> TYPE STANDARD TABLE,
<DYN_WA>,
<DYN_FIELD>.
DATA: DY_TABLE TYPE REF TO DATA,
DY_LINE TYPE REF TO DATA,
IT_STRUCTURE TYPE LVC_T_FCAT,
WA_STRUCTURE TYPE LVC_S_FCAT.
START-OF-SELECTION.
PERFORM CREATE_STRUCTURE." 定义内表的结构
PERFORM CREATE_DYNAMIC_TABLE." 按照定义的内表结构，产生一个内表
PERFORM WRITE_DATA_TO_DYNTABLE." 向动态内表中写数
PERFORM OUTPUT_DYNTABLE_DATA." 从动态内表中取数，并写到屏幕
*&---------------------------------------------------------------------*
*& Form CREATE_STRUCTURE
*----------------------------------------------------------------------*
FORM CREATE_STRUCTURE.
WA_STRUCTURE-FIELDNAME = 'COL1'." 第列名
WA_STRUCTURE-COL_POS = 1. " 表示第三列 ---
WA_STRUCTURE-INTTYPE = 'C'. " 数据类型
WA_STRUCTURE-INTLEN = 6. " 长度
APPEND WA_STRUCTURE TO IT_STRUCTURE.
WA_STRUCTURE-FIELDNAME = 'COL2'." 第 列名
WA_STRUCTURE-COL_POS = 2. " 表示第三列 ---
WA_STRUCTURE-INTTYPE = 'C'. " 数据类型
WA_STRUCTURE-INTLEN = 6. " 长度
APPEND WA_STRUCTURE TO IT_STRUCTURE.
WA_STRUCTURE-FIELDNAME = 'COL3'." 第三列名
WA_STRUCTURE-COL_POS = 3. " 表示第三列 ---
WA_STRUCTURE-INTTYPE = 'C'. " 数据类型
WA_STRUCTURE-INTLEN = 6. " 长度
APPEND WA_STRUCTURE TO IT_STRUCTURE.
ENDFORM. "CREATE_STRUCTURE
*&---------------------------------------------------------------------*
*& Form CREATE_DYNAMIC_TABLE
*----------------------------------------------------------------------*
FORM CREATE_DYNAMIC_TABLE.
CALL METHOD CL_ALV_TABLE_CREATE=>CREATE_DYNAMIC_TABLE
EXPORTING
IT_FIELDCATALOG = IT_STRUCTURE
IMPORTING
EP_TABLE = DY_TABLE.
ASSIGN DY_TABLE->* TO <DYN_TABLE>.
"表类型指针 <dyn_table> 指向 数据对象的内容.
ENDFORM. " create_dynamic_table
*&---------------------------------------------------------------------*
*& Form write_data_to_dyntable
*&---------------------------------------------------------------------*
FORM WRITE_DATA_TO_DYNTABLE .
DATA:WA_NEW_LINE TYPE REF TO DATA.
DATA:I TYPE N.
DATA:J TYPE N.
CREATE DATA WA_NEW_LINE LIKE LINE OF <DYN_TABLE>.
*建立一个与动态内表结构相同的数据对象，且数据对象为是一个结构
ASSIGN WA_NEW_LINE->* TO <DYN_WA>." 用<dyn_wa>指针指向该结构
DO 3 TIMES.
I = I + 1.
CLEAR J.
LOOP AT IT_STRUCTURE INTO WA_STRUCTURE.
J = J + 1.
ASSIGN COMPONENT WA_STRUCTURE-FIELDNAME OF STRUCTURE <DYN_WA>
TO <DYN_FIELD>.
* " 用指针<DYN_FIELD>指向工作区<DYN_WA>中的一个字段，字段名为WA_STRUCTURE-FIELDNAME.
CONCATENATE I J INTO <DYN_FIELD>." 给指针指向的字段赋值
ENDLOOP.
APPEND <DYN_WA> TO <DYN_TABLE>.
ENDDO.
ENDFORM. "WRITE_DATA_TO_DYNTABLE
*&---------------------------------------------------------------------*
*& Form OUTPUT_DYNTABLE_DATA
*----------------------------------------------------------------------*
FORM OUTPUT_DYNTABLE_DATA.
LOOP AT IT_STRUCTURE INTO WA_STRUCTURE.
WRITE: WA_STRUCTURE-FIELDNAME(5).
ENDLOOP.
LOOP AT <DYN_TABLE> INTO <DYN_WA>.
WRITE: / .
LOOP AT IT_STRUCTURE INTO WA_STRUCTURE.
ASSIGN COMPONENT WA_STRUCTURE-FIELDNAME OF STRUCTURE <DYN_WA>
TO <DYN_FIELD>.
*用指针<DYN_FIELD>指向工作区<DYN_WA>中的一个字段，字段名为WA_STRUCTURE-FIELDNAME.
WRITE : <DYN_FIELD>.
ENDLOOP.
ENDLOOP.
ENDFORM. "OUTPUT_DYNTABLE_DATA
