postback hide requirefieldvalidator asp.net

i am working with WepApplication and the problem is i have one textbox with autopostback="true" and some other textboxes and dropdowns with Validators like requirefield n regularexpression etc.. when i Click on "Submit" button,

Form is validated client side and All Requirefiled validators shows but after this problem starts when i changes text on textbox(autopostback=true") all validators are hide... but note one thing i want to fire OnTextChanged event bz if i add CausesValidation="true" it will not call OnTextChanged

so is there any way to show validator(messages) even page autopostbacked....

help me plz.

thanx in a开发者_运维问答dvance...

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Set the CauseValidation property of the TextBox to true.