data table to gridview

  protected void Page_Load(object sender, EventArgs e)
  {
 
  }
  DataTable dt;
  string sql;
 
  protected void Button1_Click(object sender, EventArgs e)
  {
  try
  {
  string ConStr = "Data source=localhost; database=trainroute;  Integrated Security=SSPI;";
  SqlConnection con = new SqlConnection(ConStr);
  con.Open();
  string source = TextBox1.Text;
  string des = TextBox2.Text;

  string query = " select * from split";
  SqlCommand cmd = new SqlCommand(query, con);
  SqlDataReader dr = cmd.ExecuteReader();
  if (dr.HasRows)
  {
  while (dr.Read())
  {
  string trno = dr[0].ToString();
  string trname = dr[1].ToString();
  string source_db = dr[2].ToString();
  string route_db = dr[3].ToString();
  string destination_db = dr[4].ToString();


  // search via source and destination

  if ((source.ToString().Trim() == source_db.ToString().Trim()) && (des == destination_db))
  {
 
  sql="select * from split where train_no='"+trno+"';";
  dt = getdata(sql);
  GridView1.DataSource = dt;
  GridView1.DataBind();
 

  }

  // Split string on spaces. This will separate all the words in a string

  // search via source and destination(route)
  if (source.ToString() == source_db.ToString())
  {
  string[] words = route_db.Split(' ');
  foreach (string word in words)
  {

  if (des == word.ToString())
  {
  sql = @"select * from split where train_no='" + trno + "';";
  dt = getdata(sql);
  GridView1.DataSource = dt;
  GridView1.DataBind();
  }
  }
  }

  //search via source(route ) and destination

  if (des.ToString() == destination_db.ToString())
  {
  string[] words = route_db.Split(' ');
  foreach (string word in words)
  {

  if (source == word.ToString())
  {
  sql = @"select * from split where train_no='" + trno + "';";
  dt = getdata(sql);
  GridView1.DataSource = dt;
  GridView1.DataBind();
  }
 
  }
  }

  // Search via source and destination in routes
  string[] words1 = route_db.Split(' ');
  int flag = 0;
  foreach (string word in words1)
  {
  if (source == word.ToString() && flag == 0)
  {
  flag = 1;
  }
  if (des.ToString() == word.ToString() && flag == 1)
  {
  sql = @"select * from split where train_no='" + trno + "';";
  dt = getdata(sql);
  GridView1.DataSource = dt;
  GridView1.DataBind();
 
  }

  }

 
  }
 
  }

 
 
  con.Close();

  }

  catch (Exception exp)
  {

  err.Text = exp.ToString();
  }
  }
  public DataTable getdata(string sql1)
  {
  DataTable dt1 = new DataTable();
  try
  {
 
  using (SqlConnection con = new SqlConnection("Data source=localhost; database=Busroute;  Integrated Security=SSPI;"))
  {
  SqlDataAdapter da = new SqlDataAdapter(sql1, con);
  da.Fill(dt1);
  }
 
  }
 
  catch (Exception ex)
  {
  err2.Text = ex.ToString();
  }
  return dt1;

  }
}

Db Structure:
tr_no, tr_name, source, route, destination

this is my code , I'm new asp.net(c#), so help me sir.. Thank You

i can't able to understand your needs.Even i give the reference.If you explain briefly means,i will give correct reference...

here is sample..

DataTable Dt = new DataTable();
                Con.Open();
                Sdap = new SqlDataAdapter("Select Query", Con);
                Sdap.Fill(Dt);
                Con.Close();
foreach (DataRow row in Dt.Rows)
                {
for (int i = 0; i <= Dt.Rows.Count; i++)
                    {
string assignname= Dt.Rows[i]["columnname"].ToString();
.
.
.
<.....Condition check...>
Gridview binding goes here...
}
}

For more details u should upload ur source code..then only i can solve ur problem...

can you post your code.... I guess you are adding just one row in datatable