OnClick Event for Button in GridView is not working - asp.net

Question

Here is my DataGridView
<asp:GridView ID="gvPredstave" runat="server" CssClass="gridview"
AlternatingRowStyle-CssClass="even" AutoGenerateColumns="True">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="btnRezervisi" runat="server" Text="Rezervisi" onclick="Button1_Click" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
This is my code for click on button in GridView
protected void Button1_Click(object sender, EventArgs e)
{
Response.Redirect("AktivneRezervacije.aspx?korisnicko_ime=" + korisnicko_ime);
conn.Close();
}
When i click on button i got this error in browser:
Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%# Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
Does anybody know the reason why is this happening.
I tried with EnableEventValidation="false" but it doesn't work.

Answer 1

I recreated the error using your gridView and binding it. The answer lies on the Page_Load event. If you have it like this:
protected void Page_Load(object sender, EventArgs e)
{
bindGridView(); //code to bind the GridView
}
You will get the exception. Change it to:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
bindGridView();
}
}
and you should not get the error anymore.

Answer 2

if the page is in postback,
you have two ways to make it work
either add a postback event on your gridview
or control in on page load.
Regarding to the conn.close();
close first the connection after redirecting it to another page.
happy coding.