Here's an example on how you would mask a row in a table through DataMiner Automation:

First you'll have to setup the helper to communicate with the back-end.

var helper = new DMAObjectRefTreeHelper();
helper.SetupHelper(Engine.SLNetRaw.HandleSingleResponseMessage);

Then through that helper you can mask the row by stating which object needs to be masked and which mask info needs to be applied.

helper.ChangeMaskInfo(new DMAObjectRefTree(
new RowID(
162, // DataMiner ID
350, // Element ID
1500, // Table ID
0, // Column Index
"eth0")), // Row Index
new MaskInfo()
{
DoMask = true,
MaskType = MaskType.UntilUnmask,
Reason = "Maintenance"
},
new CPECrawlerConfiguration());

Unmasking can be done by setting the DoMask property to false and the MaskType property can be used to apply a different kind of masking strategy.
In the example the object will be masked until it's later manually unmasked again, but there's also the option to mask it for a certain period of time (MaskType.UntilTimeElapsedOrUnmask) or automatically unmask it if an alarm would be cleared again (MaskType.UntilClearanceOrUnmask).