要显示警告框的变量值

嗨朋友我在ASP.NET 3.5中新的，我要显示Alert对话框中的变量的值，所以请给我建议。这里是我的代码。

public partial class WebForm1 : System.Web.UI.Page

    {

        int sum3;

 

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            { 

                DataTable dTable = new DataTable("mainTable");

 

                DataColumn Name = new DataColumn("Name");

                dTable.Columns.Add(Name);

 

                DataColumn Marks = new DataColumn("Marks");

                dTable.Columns.Add(Marks);

 

                DataColumn Marks2 = new DataColumn("Marks2");

                dTable.Columns.Add(Marks2);

 

                DataColumn Total = new DataColumn("Total");

                dTable.Columns.Add(Total);

 

                int sum = 0;

                int sum2 = 0;

 

                DataRow dRow = null;

                for (int i = 0; i < 5; i++)

                {

                    dRow = dTable.NewRow();

                    dRow["Name"] = i + " - Sagar";

                    dRow["Marks"] = i;

                    sum += i;

                    dRow["Marks2"] = i + 5;

                    sum2 += i + 5;

                    dRow["Total"] = i + i + 5;

                    sum3 += i + i + 5;

                    dTable.Rows.Add(dRow);

                }

 

                Page.ClientScript.RegisterStartupScript(this.GetType(), "alert", "showAlert(" + sum3.ToString() + ");", true);

 

                //dRow = dTable.NewRow();

                //dRow["Name"] = "Total";

                //dRow["Marks"] = sum;

                //dRow["Marks2"] = sum2;

                //dRow["Total"] = sum3;

                //dTable.Rows.Add(dRow);



                aspDataGrid.DataSource = dTable;

                aspDataGrid.DataBind();

            }

        }

 

        protected void btn_Submit_Click(object sender, EventArgs e)

        {

            marks1.Text = "Total Marks : " + sum3.ToString();

            Page.ClientScript.RegisterStartupScript(this.GetType(), "alert", "showAlert(" + sum3.ToString() + ");", true);

        }

}