Configure a peoplepicker inside a dynamic grid. In the properties of the PeoplePicker, there is a property “Validate on Save”. If an invalid user is entered in People Picker’s textbox and if “Validate on Save” is checked, the data should not be saved to the List/SQL.
This feature is illustrated below.
Drag and drop a dynamic grid control. Configure the dynamic grid control as shown,
Click on the property button of the people picker control, the property window will be displayed.
Now configure the insert command on the trigger of a button,
On the preview enter a valid name as well as an invalid name.