Uploading to SQL Server database offline - winforms

Question

I'm trying to achieve a method whereby when a user upload a PDF document to a SQL Server database. The data would be uploaded instantly if network is available, but if there is no internet connection - the data would be stored somewhere else and be uploaded when internet connection is back. Please any idea how to achieve this?
Here is my code for the upload:
//CheckIfNetworkConnected( ) ;
Ping p = new Ping();
try
{
string host = "www.google.com";
//bool result = false;
PingReply reply = p.Send(host, 3000);
if (reply.Status == IPStatus.Success)
{
// Display form modelessly
pleaseWait.Show();
// Allow main UI thread to properly display please wait form.
Application.DoEvents();
using (SqlConnection con = new SqlConnection("Server=tcp:mycompany.database.windows.net,1433;Initial Catalog=DBmycompany;Persist Security Info=False;User ID=abubakarkabiru;Password=wordpass123#;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30"))
{
FileStream fStream = File.OpenRead(filepath);
byte[] contents = new byte[fStream.Length];
fStream.Read(contents, 0, (int)fStream.Length);
fStream.Close();
con.Open();
cmd = new SqlCommand("Insert into document values(#Staffname, #unit, #sites, #docname, #dateofreciept, #descriptions, #doc, #category, #housetype)", con);
if (textBox1.Visible == true)
{
cmd.Parameters.AddWithValue("#Unit", textBox1.Text);
cmd.Parameters.AddWithValue("#Staffname", textBox2.Text);
}
else
{
cmd.Parameters.AddWithValue("#Staffname", comboDesigner.SelectedItem.ToString());
cmd.Parameters.AddWithValue("#unit", comboUnit.SelectedItem.ToString());
}
cmd.Parameters.AddWithValue("#category", comboCategory.SelectedItem.ToString());
if (string.IsNullOrWhiteSpace(txtdocname.Text))
{
errorProvider1.SetError(txtdocname, "Compulsory");
}
else
{
cmd.Parameters.AddWithValue("#docname", string.IsNullOrWhiteSpace(txtdocname.Text));
}
cmd.Parameters.AddWithValue("#dateofreciept", dateTimePicker1.Value.ToShortDateString());
cmd.Parameters.AddWithValue("#doc", contents);
cmd.Parameters.AddWithValue("#sites", string.IsNullOrWhiteSpace(comboSites.ToString())
? (Object)comboSites.SelectedItem.ToString()
: (Object)DBNull.Value);
cmd.Parameters.AddWithValue("#housetype", string.IsNullOrWhiteSpace(comboHouseType.ToString())
? (Object)comboHouseType.SelectedItem.ToString()
: (Object)DBNull.Value);
cmd.Parameters.AddWithValue("#descriptions", string.IsNullOrWhiteSpace(txtDesc.Text)
? (object)txtDesc.Text
: (object)DBNull.Value);
var i = cmd.ExecuteNonQuery();
if (i > 0)
{
MessageBox.Show("Successful");
this.notifyIcon1.Icon = this.Icon;
this.notifyIcon1.ShowBalloonTip(600, "Upload Notice", "New Document has been Uploaded", ToolTipIcon.Info);
//notifyUpload();
}
con.Close();
}
pleaseWait.Hide();
cleaBoxes();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}