Use ReturnValues if you want to get the item attributes as they appeared either before or after they were updated. For UpdateItem, the valid values are:

• NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This is the default for ReturnValues.)
• ALL_OLD - If UpdateItem overwrote an attribute name-value pair, then the content of the old item is returned.
• UPDATED_OLD - The old versions of only the updated attributes are returned.
• ALL_NEW - All of the attributes of the new version of the item are returned.
• UPDATED_NEW - The new versions of only the updated attributes are returned.

Constraints:

Allowed Values

NONE, ALL_OLD, UPDATED_OLD, ALL_NEW, UPDATED_NEW

public string ReturnValues { get; set; }