Hi,
Try this:
OnClientClick='<%# String.Format("javascript:return redirect(\"{0}\")", Eval("idProduct").ToString()) %>'
And then change your JavaScript function to get a parameter(idProduct).
Your function:
<script language="javascript">
function redirect(idProduct) {
window.location = "Product_Detail.aspx?idProduct=" + idProduct;
}
</script>
Cheers