سلام

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
string path1 = @"D:test.backup";
string backup = @"backup database test to disk='"+path1+"'";

SqlConnection con = new SqlConnection();
SqlCommand cmd = new SqlCommand();
con.ConnectionString = "server=(local);database=test;trusted_connection=t rue";
if (con.State != ConnectionState.Open)
{
con.Open();
}

cmd.Connection = con;
cmd.CommandText = backup;
cmd.ExecuteNonQuery();
con.Close();
}

داخل درایو d فایل test.backup میسازه