RequiredFieldValidator:
Verifies whether a control contains data
CompareValidator:
Verifies whether an entered item matches an entry in another control
RangeValidator:
Verifies whether an entered item is between two values
RegularExpressionValidator:
Verifies whether an entered item matches a specified format
CustomValidator:
Verifies the validity of an entered item using a client-side script or a server-side code, or both
ValidationSummary:
Displays validation errors in a central location or display a general validation error description
