Question

        [WebMethod]
    public List< string> HelloWorld(string prefixText)
    {
        SqlConnection con = new SqlConnection("Database=bluedd;Server=(local);Integrated Security=SSPI");
        con.Open();
        SqlCommand cmd = new SqlCommand("select user_master.first_name from user_master where first_name like @Name+'%'", con);
        cmd.Parameters.AddWithValue("@Name", prefixText);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        List<string> CountryNames = new List<string>();

        for (int i = 0; i < dt.Rows.Count; i++)
        {
           CountryNames.Add(dt.Rows[i].ToString());
        }
        return CountryNames;
    }

This code returns System.Data.DataRow is there any casting problem
I am very new in s/w Development, any help will be appreciated

Answer 1

Your code is returning the data row. To return the column you would do something like

CountryNames.Add(dt.Rows[i][0]);

I think what you want is to replace your for loop with this.

        foreach(DataRow row in dt.Rows)
           {
              CountryNames.Add(row[0]);
           }
        return CountryNames;