Hello Winan,
Highlight the datagrid and go to properties. Goto the TableStyles property and click on the ... Add a TableStyle. Select it, goto the GridColumnStyles property, and click on the ... Here you can add the columns you need. You can set the Alignment, HeaderText, Width, and the MappingName (if binding to a datatable it is the name of the field)
I don't know how to lock the size of the column, but I hope the above info helps.
Randy Belcher
AFG Industries, Inc.