Calculate Column total and open new popup window on single Button Click in ASP.Net

Hello

Can i merge 2 button (code) in 1

First i must check users, then calculate total users, second open new window popup 

<asp:Button ID="btnCount" runat="server" Font-Bold="True" Font-Names="Arial" Font-Size="14pt" AutoPostBack="true" OnClick="OnCount" Text="حصر  المهندسين والاشرافين" />
<asp:Button ID="btnShow0" runat="server" Text="نموذج بدل موقع" Font-Bold="True" Font-Size="16pt" OnClick="ShowRDLCbtn" Font-Names="Arial" CssClass="auto-style51" BackColor="#0066FF" />

        protected void OnCount(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("OPsec");

            foreach (GridViewRow row in GridView1.Rows)
            {
                CheckBox cbRow = row.FindControl("CheckBox1") as CheckBox;

                if (cbRow.Checked)
                {
                    string OPsec = row.Cells[6].Text;
                    dt.Rows.Add(OPsec);
                }
            }
            GetCounts(dt);        

        protected void ShowRDLCbtn(object sender, EventArgs e)
        {
            Session["MsgBox1"] = TextBox12.Text;
            Session["MsgBox2"] = TextBox13.Text;
            Session["MsgBox3"] = lblUsa.Text;
            Session["MsgBox4"] = lblUk.Text;
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[7] {

            new DataColumn("Id"), new DataColumn("name"), new DataColumn("civilid"), new DataColumn("jop"), new DataColumn("markazel3mal"), new DataColumn("OPsec"), new DataColumn("OPusers")});

            foreach (GridViewRow row in GridView1.Rows)
            {
                if ((row.FindControl("CheckBox1") as CheckBox).Checked)
                {
                    string id = row.Cells[1].Text;
                  
                    string name = (row.FindControl("lblidnamev") as Label).Text.Trim();
                    string civilid = (row.FindControl("lblidcivilv") as Label).Text.Trim();

                    string jop = (row.FindControl("lbljop") as Label).Text.Trim();
                    string markazel3mal = (row.FindControl("lblel3malv") as Label).Text.Trim();
                    string OPusers = row.Cells[6].Text;
                    string OPsec = row.Cells[7].Text;
                    
                    dt.Rows.Add(id, name, civilid, jop, markazel3mal, OPsec, OPusers);

                    Session["GridViewRow"] = dt;
                    string url = "/Admin/WebForm4report.aspx";
                    string s = "window.open('" + url + "', 'popup_window', 'width=800,height=950,left=100,top=100,resizable=yes');";
                    ClientScript.RegisterStartupScript(this.GetType(), "script", s, true);
                }
            }
        }