Gets whether the current cell's value should be stored in a custom data source.
true if the current cell's value needs to be saved in a custom data source.
If the IsSetData property is set to true (and consequently the CustomColumnDataEventArgs.IsGetData property is set to false) the CustomColumnDataEventArgs.Value parameter identifies the value which has been set for the current cell in the grid. This should be stored in your data source by the event handler.
If the IsSetData property returns false (and consequently the CustomColumnDataEventArgs.IsGetData property is set to true) the data for the currently processed cell should be supplied via the event handler. For this purpose retrieve a value from your data source based upon the current row and unbound column and assign it to the event's CustomColumnDataEventArgs.Value parameter.