public virtual void Update ()
The following code example updates the display name, default value, and description for the specified field.
SPSite oSiteCollection = SPContext.Current.Site; SPList oList = oSiteCollection.AllWebs["Site_Name"].Lists["List_Name"]; SPField oField = oList.Fields["Field_Name"]; oField.DefaultValue = "Default_Value"; oField.Description = "Description"; oField.Title = "New_Field_Title"; oField.Update();