How to Generate/Print Multiple StudentID from Datagridview ?

I am working on desktop application. i tried some code for generating id and it will print only one Id at a time.

Now i want to print/generate multiple Id's based on Roll No from datagridview.

This is my code...

and this code is used for getting this 2 values which passed from StudentReport Form

int Getroll;
string GetClass;
public GenerateIDCard(int RollNo,string Class)
{
con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString);
SqlConnection.ClearPool(con);
con.Open();
InitializeComponent();
Getroll = RollNo;
GetClass = Class;
}
public void GetStudentInfo()
{
SqlCommand cmd = new SqlCommand("select Sname,Class,DOB,Mobileno,Address,studimg from StudentRegister where Rollno='"+Getroll+"' and Class='" + GetClass + "'", con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
lblstudentname.Text = dr["Sname"].ToString();
lblstudclass.Text = dr["Class"].ToString();
lbldob.Text = DateTime.Parse(dr["DOB"].ToString()).ToString("dd-MMM-yy");
lblstudentmobile.Text = dr["Mobileno"].ToString();
lblstudentsaddress.Text = dr["Address"].ToString();
Studentimage_picname = dr["studimg"].ToString();
}
dr.Close();
studentpath = "E:\\CoachingClassImages\\StudentIDImages\\" + Studentimage_picname;
pictureBoxstudent.Image = new Bitmap(studentpath);
}

So help me how can i do this....