SharePoint: Problem with programatically updating custom field type column value 
I have created a custom field type(say 'Sample') in SharePoint which is based on 'multiline text' field type. Now I have created a new column(say 'test') of type 'Sample' in a list. I created some list items. I can edit the column value successfully from SharePoint UI (through edit form). but when I try to modify the value of 'test' column programatically for any list item, value of 'test' column for that list item becomes null/empty.
any idea Why this probem is occuring??  
SharePoint: Problem with programatically updating custom field type column value 
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I have created a custom field type(say 'Sample') in SharePoint which is based on 'multiline text' field type. Now I have created a new column(say 'test') of type 'Sample' in a list. I created some list items. I can edit the column value successfully from SharePoint UI (through edit form). but when I try to modify the value of 'test' column programatically for any list item, value of 'test' column for that list item becomes null/empty.
any idea Why this probem is occuring??  