Returns the text stored at the given column index in the receiver,
or empty string if the text has not been set.
@param index the column index
@return the text stored at the given column index in the receiver
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
</ul>
Returns the text stored at the given column index in the receiver, or empty string if the text has not been set.
@param index the column index @return the text stored at the given column index in the receiver
@exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> </ul>
@since 3.1