How to add text file to data table column?

below is my table creation code and i am getting data table with DB values .How i can add my txt file as first column

private static DataTable LoadTable(string connectionString, string query, string tableName)
{
using (var connection = new OdbcConnection(connectionString))
using (var command = new OdbcCommand(query, connection))
using (var adapter = new OdbcDataAdapter(command))
{
command.CommandTimeout = 0;
var table = new DataTable(tableName);
adapter.Fill(table);
return table;
}
}