RequiredValidator ?

<asp:TextBox id="TextBox_search" runat="server"></asp:TextBox>

<asp:TextBox id="TextBox_subscribe" runat="server"></asp:TextBox>

<asp:Button id="Button_search" runat="server" Text="Search"></asp:Button>

<asp:Button id="Button_submit" runat="server" Text="Submit"></asp:Button>

<asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" ErrorMessage="Email must not left blank" ControlToValidate="TextBox_subscribe"></asp:RequiredFieldValidator>

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I had 2 buttons with different purpose, but when I pressed the search button for textbox_search(in empty) which I never validate to it, message error on textbox_subscribe came out "email must not left blank".
So how to make RequiredFieldValidator only work with Button_submit not Button_search ?

Thanks in advance.

With the first scenario maybe we can use cause validation property.
But how if the second scenario like this, each textbox have their own validator and must independent, so if we press search button(in empty field) only 'Search Query Required' message appear ???

=====================================
<asp:TextBox id="TextBox_search" runat="server"></asp:TextBox>

<asp:TextBox id="TextBox_subscribe" runat="server"></asp:TextBox>

<asp:Button id="Button_search" runat="server" Text="Search"></asp:Button>

<asp:Button id="Button_submit" runat="server" Text="Submit"></asp:Button>

<asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox_subscribe" ErrorMessage="Email Required" Display="Dynamic"></asp:RequiredFieldValidator>

<asp:RequiredFieldValidator id="RequiredFieldValidator2" runat="server" Display="Dynamic" ErrorMessage="Search Query Required" ControlToValidate="TextBox_search"></asp:RequiredFieldValidator>
=====================================

Thanks again..

Sorry I am just a beginner.., still need help :)