Can't put column name into GetString

Question

I have got this code:

public void chyt_data()
    {
        try
        {


            SqlCommand novyprikaz = new SqlCommand("SELECT * FROM zajezd WHERE akce=" + currentrowstring, spojeni);
            spojeni.Open();
            SqlDataReader precti = novyprikaz.ExecuteReader();

            if (precti.Read())
            {

                zakce.Text = precti.GetString(0);
                zname.Text = precti.GetString(2);

         }

     }
     catch (Exception ex)
     {
         MessageBox.Show("Chybové hlášení2: " + ex.Message.ToString());
     }

     spojeni.Close();
   }

if i insert column name in it it like this:

    zakce.Text = precti.GetString("akce");

it wouldn't work.

May someone please help me solve this out ? Thank you so much

it gives two errors:

1:Error 1 The best overloaded method match for 'System.Data.Common.DbDataReader.GetString(int)' has some invalid arguments

2: Error 2 Argument 1: cannot convert from 'string' to 'int'

You can't do that. `SqlDataReader.GetString()` accepts only parameter with `int` type (http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.getstring.aspx) — Andrey Gordeev, Jul 10 '13 at 11:44
Thanks so much, so if the value is char, I should use GetChar right? — Marek, Jul 10 '13 at 11:46
@MarekŠíp nope; GetChar is not supported on SqlDataReader - it doesn't work — Marc Gravell, Jul 10 '13 at 11:49

score 6 · Accepted Answer · answered Jul 10 '13 at 11:50

6

You need the GetOrdinal function

zakce.Text = precti.GetString(precti.GetOrdinal("akce"));
zname.Text = precti.GetString(precti.GetOrdinal("name"));

answered Jul 10 '13 at 11:50

Bob Vale

18,094
1
42
49

score 2 · Answer 2 · answered Jul 10 '13 at 11:51

For things like:

zakce.Text = precti.GetString("akce");

there are several options:

zakce.Text = (string)precti["akce"];

or if you aren't sure that it is a string:

zakce.Text = Convert.ToString(precti["akce"]);

or:

int idx = precti.GetOrdinal("akce");
zakce.Text = precti.GetString(idx);

score 1 · Answer 3 · answered Jul 10 '13 at 11:48

1

SqlDataReader.GetString() method accepts only parameter with int type. So you have to pass column number instead of column name to get the value.

See MSDN for more info.

answered Jul 10 '13 at 11:48

Andrey Gordeev

30,606
13
135
162

score 1 · Answer 4 · answered Jul 10 '13 at 11:50

1

Do like this

  if (precti.Read())
        {

            zakce.Text = precti[0].ToString();
            zname.Text = precti[2].ToString();

        }

answered Jul 10 '13 at 11:50

Rajeev Kumar

4,901
8
48
83

Can't put column name into GetString

4 Answers4