I want to send emails through application insight for certain events like validation failure, mandatory field not present etc.
I know Application insight doesn't have facility to support Email facility directly, but it can send an alert when a metric crosses a threshold.
Alerts can be set on custom metrics, though not custom events. Write some code to increase a metric when the event occurs.
I am referring below link to achieve email sending functionality.
But I am facing one problem. Alarm option is not in metric. Please see below images.