BACK UP & RESTORE SQL SERVER DB USING C# ASP.NET

//aspx Page
 <div> 
            <table cellpadding="10" cellspacing="10" style="border: solid 10px red; background-color: Skyblue;" 
                width="90%" align="center"> 
                <tr> 
                    <td style="height: 35px; background-color: Yellow; font-weight: bold; font-size: 16pt; 
                        font-family: Times New Roman; color: Red" align="center"> 
                        Backup/Restore SQL Server DataBase 
                    </td> 
                </tr> 
                <tr> 
                    <td align="center"> 
                        <asp:Label ID="lblError" runat="server" ForeColor="Red"></asp:Label> 
                    </td> 
                </tr> 
                <tr> 
                    <td align="center"> 
                        <asp:Button ID="btnBackup" runat="server" Text="Backup DataBase" OnClick="btnBackup_Click" /> 
                    </td> 
      
                </tr>  
                  <tr> 
                    <td align="center"> 
                        <asp:Button ID="btnrestore" runat="server" Text="Restore DataBase" OnClick="btnrestore_Click" /> 
                    </td> 
      
                </tr> 
            </table> 
        </div>

//Codebehind Page
using System.IO;

 //global var
  string strQuery = string.Empty;
        string backupDIR = "D:\\BackupDB";
        SqlConnection con = new SqlConnection();
        SqlCommand sqlcmd = new SqlCommand();


 protected void btnBackup_Click(object sender, EventArgs e)
        {
            con.ConnectionString = @"Server=REFLEXIRP\SQLEXPRESS;database=testdb;uid=sa;password=sasa@123;";

            if (!Directory.Exists(backupDIR))
            {
                Directory.CreateDirectory(backupDIR);
            }
            try
            {
                string[] pdfFiles = Directory.GetFiles("D:\\BackupDB\\", "*.bak");
                string str = pdfFiles[0].ToString();
                if (str!=null)
                {
                    Array.ForEach(Directory.GetFiles(@"D:\\BackupDB\\", "*.bak"), File.Delete);
                    con.Open();
                    sqlcmd = new SqlCommand("backup database testdb to disk='" + backupDIR + "\\" + DateTime.Now.ToString("ddMMyyyy_HHmmss") + ".Bak'", con);
                    sqlcmd.ExecuteNonQuery();
                    con.Close();
                    lblError.Text = "Backup database successfully";
                }

            }
            catch (Exception ex)
            {
                lblError.Text = "Error Occured During DB backup process !<br>" + ex.ToString();
            }
        }  
        protected void btnrestore_Click(object sender, EventArgs e)
        {         

            string[] pdfFiles = System.IO.Directory.GetFiles("D:\\BackupDB\\", "*.bak");           
            string str = pdfFiles[0].ToString();
            con.ConnectionString = @"Server=REFLEXIRP\SQLEXPRESS;database=testdb;uid=sa;password=sasa@123;";         
            con.Open();
            sqlcmd = new SqlCommand("USE MASTER RESTORE DATABASE testdb FROM DISK =   '" + str + "' WITH REPLACE", con);

            sqlcmd.ExecuteNonQuery();
            con.Close();        

            lblError.Text = "Restored database successfully";

        }