Counting the checkboxs and checkboxlixt validation

Dear ASP.Net Gurus,
I have the following simple logic on my buttionclick. Along with this, I need to implement my checkboxlist validation and need to find if more than one boxes are checked.
I attemtpted diffferent things by goggling, nothing worked. I would appriciate your help.
 
protected void Button1_Click(object sender, EventArgs e)
    {
       
        foreach (ListItem item in CheckBoxList1.Items)
        {
            if (item.Selected)
            {
                //item.Text and item.Value will give you other properties... 
            ...