Hi Budianto,
You sould put the Define Class code in any .PRG file. Then instead of using the default columns as you do :
with thisform.grid1
.column1.controlsource='tmpfile->field'
.column1.header1.caption='MATERIAL NAME'
.column1.header1.forecolor=rgb(255,255,255)
.column1.header1.backcolor=rgb(97,105,156)
.column1.width=340
....
endwith
Do the following...
with thisform.grid1
.ColumnCount = 0
* do the following for each of your columns
.AddObject("MyColumnName","MyColumn")
.column1.controlsource='tmpfile->field'
.MyColumnName.header1.caption='MATERIAL NAME'
.MyColumnName.header1.forecolor=rgb(255,255,255)
.MyColumnName.header1.backcolor=rgb(97,105,156)
.MyColumnName.width=340
....
endwith
Hope it helps