如何在表单提交期间阻止新标签打开

Question

我有一个要提交的注册表单，它执行一些活动，例如将用户详细信息保存到数据库，将证明作为图像发送到数据库，并向用户发送电子邮件给出用户名和密码。单击提交按钮，控制转到新选项卡，然后只有控件转到CS文件。

我的代码是：

protected void sub2_Click(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    incentiveClass.dbPerform dbc = new incentiveClass.dbPerform();

    string custname = iname.Value;
    custemail = iemail.Value;

    string datebir = datepicker.Value;


    string cadd1 = addr1.Value;
    string cadd2 = add2.Value;
    dt = dbc.conid(DropDownList1.SelectedValue);
    string ctry = dt.Rows[0]["CountryID"].ToString();
    string sta = state1.Value;
    string city = icity.Value;
    string pin = ipin.Value;
    string pann = ipan.Value;
    string cno = icno.Value;
    string mobil = imobe.Value;
    string faxx = ifx.Value;

    pwd = PasswordCreation(10);

    string filePath = addproof.PostedFile.FileName;
    string filename = Path.GetFileName(filePath);
    string ext = Path.GetExtension(filename);
    string contenttype = String.Empty;

    //Set the contenttype based on File Extension
    switch (ext)
    {
        case ".doc":
            contenttype = "application/vnd.ms-word";
            break;
        case ".docx":
            contenttype = "application/vnd.ms-word";
            break;
        case ".xls":
            contenttype = "application/vnd.ms-excel";
            break;
        case ".xlsx":
            contenttype = "application/vnd.ms-excel";
            break;
        case ".jpg":
            contenttype = "image/jpg";
            break;
        case ".png":
            contenttype = "image/png";
            break;
        case ".gif":
            contenttype = "image/gif";
            break;
        case ".pdf":
            contenttype = "application/pdf";
            break;
    }
    if (contenttype != String.Empty)
    {

        Stream fs = addproof.PostedFile.InputStream;
        BinaryReader br = new BinaryReader(fs);
        add1 = br.ReadBytes((Int32)fs.Length);

        Label1.ForeColor = System.Drawing.Color.Green;
        Label1.Text = "File Uploaded Successfully";
    }
    else
    {
        Label1.ForeColor = System.Drawing.Color.Red;
        Label1.Text = "File format not recognised." +
          " Upload Image/Word/PDF/Excel formats";
        Response.Redirect("register.aspx");
    }

    string filePath1 = pancopy.PostedFile.FileName;
    string filename1 = Path.GetFileName(filePath1);
    string ext1 = Path.GetExtension(filename1);
    string contenttype1 = String.Empty;

    //Set the contenttype based on File Extension
    switch (ext1)
    {
        case ".doc":
            contenttype1 = "application/vnd.ms-word";
            break;
        case ".docx":
            contenttype1 = "application/vnd.ms-word";
            break;
        case ".xls":
            contenttype1 = "application/vnd.ms-excel";
            break;
        case ".xlsx":
            contenttype1 = "application/vnd.ms-excel";
            break;
        case ".jpg":
            contenttype1 = "image/jpg";
            break;
        case ".png":
            contenttype1 = "image/png";
            break;
        case ".gif":
            contenttype1 = "image/gif";
            break;
        case ".pdf":
            contenttype1 = "application/pdf";
            break;
    }
    if (contenttype1 != String.Empty)
    {

        Stream fs1 = pancopy.PostedFile.InputStream;
        BinaryReader br1 = new BinaryReader(fs1);
        pan = br1.ReadBytes((Int32)fs1.Length);


        Label2.ForeColor = System.Drawing.Color.Green;
        Label2.Text = "File Uploaded Successfully";
    }
    else
    {
        Label2.ForeColor = System.Drawing.Color.Red;
        Label2.Text = "File format not recognised." +
          " Upload Image/Word/PDF/Excel formats";
        Response.Redirect("register.aspx");
    }


    Guid g = Guid.NewGuid();
    string random = g.ToString();

    dbc.Cuscode = random.Substring(0, 4);
    dbc.Customer_name = custname;
    dbc.Email = custemail;
    dbc.Dateob = datebir;

    dbc.Add1 = cadd1;
    dbc.Add2 = cadd2;
    dbc.Country = ctry;
    dbc.State = sta;
    dbc.Pin = pin;
    dbc.Panno = pann;
    dbc.Phone = cno;
    dbc.Mobile1 = mobil;
    dbc.Fax = faxx;
    dbc.Pawd = pwd;
    dbc.Bytes = add1;
    dbc.Bytes1 = pan;
    int flag = dbc.regstr(icity.Value);
    if (flag == 1)
    {
        Page.ClientScript.RegisterStartupScript(typeof(Page), "MessagePopUp", "alert('Registration Successfull!!! Mail will be sent to your Email Id!!!');", true);
    }

    try 
    {
        Response.Redirect("userhome.aspx",false);
        SendMail();              
    }
    catch(Exception ex)
    {
        ShowMessage(ex.Message);
    }
}