how to disable server side validation on asp.net web forms from browser? - asp.net

Question

I wanted to disable asp.net validation server controls from browser. I checked online but did not find any way to disable the server side validation; it can be disabled only on the client side using JS/jQuery.
Here is the scenario: I have a checkbox and selecting which displays a set of text boxes. Only if the checkbox is checked, required field validator should fire for the text boxes. I don't want to call a postback on checkbox. Actually those chceck boxes will be generated with jQuery templating so postback is not an option to enable disable validtion.
I would like to know whether there is any way we can enable disable the .CausesValidation property for the controls from browser using some setting? Or is there a way to capture the controls which are to be considered for validation slectively in some event before page_load?
[Update]
Based on Accepted answer, here is my solution:
<form id="form1" runat="server">
<div>
<asp:TextBox ID="textbox1" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="req1" ControlToValidate="textbox1" runat="server"
ErrorMessage="enter text"></asp:RequiredFieldValidator>
<asp:TextBox ID="textbox2" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="req2" ControlToValidate="textbox2" runat="server"
ErrorMessage="enter text for 2"></asp:RequiredFieldValidator>
<asp:CheckBox ID="check1" runat="server" Text="choose" />
<asp:Button ID="submitBtn" runat="server" OnClick="submitBtn_Click" Text="submit" />
<asp:CustomValidator ID="cvBox" runat="server" ErrorMessage="Error" ValidationGroup="prueba"
OnServerValidate="Validarcaja"></asp:CustomValidator>
<asp:ValidationSummary ID="summary" runat="server" />
</div>
</form>
protected void Page_Load(object sender, EventArgs e)
{
req1.Enabled = false;
req2.Enabled = false;
}
protected void submitBtn_Click(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
Page.Validate();
if (Page.IsValid)
{
Response.Write("valid form");
}
else
{
Response.Write("invalid form");
}
}
}
protected void Validarcaja(object source, ServerValidateEventArgs args)
{
if (check1.Checked)
{
req1.Enabled = true;
req1.Validate();
}
}

Answer 1

The solution for me would be to use a CustomValidator with a OnServerValidate method.
In the OnServerValidate method I would check if the checkbox is checked, in that case I would verify if the textboxes are filled. It is not necessary to do any change in the CausesValidation property.
The only condition is not to include the property "ControlToValidate". A CustomValidator does not fire if the textbox is empty that's why.
So the code would be like this:
<asp:ValidationSummary ID="vs" runat="server" ValidationGroup="prueba" />
<asp:CheckBox ID="chb" runat="server" Text="Check" />
<asp:TextBox ID="txbBox" runat="server"></asp:TextBox>
<asp:CustomValidator ID="cvBox" runat="server" ErrorMessage="Error" ValidationGroup="prueba"
OnServerValidate="Validarcaja"></asp:CustomValidator>
<asp:Button ID="btn" runat="server" Text="Prueba" />
And the codebehind:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
Page.Validate();
}
}
protected void Validarcaja(object source, ServerValidateEventArgs args)
{
if (chb.Checked)
{
if (txbBox.Text == String.Empty)
{
cvBox.IsValid = false;
}
}
}