How to read values of a particular column from a datatable.

foreach(DataRow row in DataTable.Rows)
{
//get the values here
}

Well, it depends on the way datatable is formed. Better if you have column names defined. Once there, it would be something like:

string currentCellValue = string.Empty;

foreach(DataRow dr in myTable.Rows)
{
   // Here you get access to values at cell level.
   // Place your desired logic here.
 
   currentCellValue = dr["myColumnName"].ToString();
   // In case column names are not defined then
   // Assuming you need 3rd column value then
   currentCellValue = dr[2].ToString();
}

Well there are two ways to loop through the data(s). Whether you want to loop through connected or through the disconnected way. If I'm not mistaken the above answers by our members are disconnected way(correct me if wrong).

Below example is the way to loop through the database while connected:

try
{
      conn.Open();

      string commString = "SELECT * FROM database_table";

      SqlCommand comm = new SqlCommand(commString, conn);
      SqlDataReader reader = null;

      reader = comm.ExecuteReader();

      while (reader.Read())
      {
          if (reader["myID"].ToString() == textSearch.Text)
          {
              textID.Text = reader["myID"].ToString();
              textName.Text = reader["myName"].ToString();
              textIC.Text = reader["myIC"].ToString();
              textAddress.Text = reader["myAddress"].ToString();
              textContact.Text = reader["myContact"].ToString();
          }
      }
  }
  finally
  {
      conn.Close();
  }

myID,myName... are the columns for each row in the table

var test = (from obj in dt.AsEnumerable()
select new
{
test = obj["FirstName"].ToString()
}).ToList();