How many types of validation controls are provided by ASP.NET 

The six main types of validation controls are as follows:-

1) Required Field Validator: This validator checks whether the control have any value . It is used when you want that the control should not be empty.

2) Range Validator: This validator  checks if the value in validated control is in that specific range. For example the TxtCustomerCode should not be more than eight in length.

3) Compare Validator: This validator checks that the value in controls should match the value in other control. Example the Textbox TxtPie should be equal to 3.14.

4) Regular Expression Validator: Whenever  we want that the control value should match with a specific regular expression.

5) Custom Validator:  This validator  is used to define the UserDefined validation.

6) Validation Summary : This validator displays summary of all current validation errors.