Re: I do not understand why the error ! :S - C# Discussion Boards

1-Jun-11 2:31

private void Action(int ust_id) 
{ 
     MySqlCommand cmd = new MySqlCommand("Select * From kategoriler_tablo Where UstKategoriId=" + ust_id.ToString(), c); 
     c.Open(); 
     MySqlDataReader r = cmd.ExecuteReader(); 
     while (r.Read()) { 

          if (ust_id != 0) { 
               treeView1.Nodes.Find(ust_id.ToString(), true)(0).Nodes.Add(r("id").ToString(), r("KategoriAdi").ToString()); 

          } else { 
               treeView1.Nodes.Add(r("id").ToString(), r("KategoriAdi").ToString()); 
          } 
          Action(Convert.ToInt32(r("id"))); 
     } 
     r.Close(); 
     c.Close() 
} 

private void Button1_Click(System.Object sender, System.EventArgs e) 
{ 
    if (c.State != ConnectionState.Open) { 
     } 
     TreeView1.Nodes.Clear(); 
     TreeView1.Update(); 
     c.close(); 
     Action(0); 
}

This code does not work. I could not understand where the fault is
http://www.imageupload.org/?d=2E926FEF1[^]

PIEBALDconsult1-Jun-11 2:50

PIEBALDconsult

1-Jun-11 2:50

I guess an earlier operation didn't close the connection. Find out where, and also check the state before opening and closing.

You may want to put the close in a finally.

Eddy Vluggen1-Jun-11 2:59

Eddy Vluggen

1-Jun-11 2:59

It'd be easier to create a new connection in the Action method and wrapping it in a using directive; that way it'll always use it's own connection and it'll always close it when done.

Bastard Programmer from Hell Suspicious | :suss:

Not Active1-Jun-11 2:59

1-Jun-11 2:59

Well as the error indicates the connection is still opened from a previous attempt or some other method.

Since you are not using any try/catch blocks the code could have failed at any point between the Open and Close calls thus leaving the connection open.

Make use of the using statement

using(SqlConnection conn = new SqlConnection("..."))
{
  using(SqlCommand cmd = new SqlCommand("...", conn))
  {
    // Do actions here
  }
}

With this the connection and command will be disposed of regardless of whether a failure has occurred.

You should learn to program defensively also.

if(conn.State != ConnectionState.Open)
  conn.Open();

And lastly, use parameterized queries rather than concatenate a string for the command.

I know the language. I've read a book. - _Madmatt

modified on Wednesday, June 1, 2011 9:34 AM

ismail201-Jun-11 3:05

1-Jun-11 3:05

which should help me get the line?

Not Active1-Jun-11 3:21

1-Jun-11 3:21

What?????

I know the language. I've read a book. - _Madmatt

ismail201-Jun-11 3:29

1-Jun-11 3:29

which line is wrong in my code?

Not Active1-Jun-11 3:32

1-Jun-11 3:32

All of it. Please read the suggestions you have been given

I know the language. I've read a book. - _Madmatt

ismail201-Jun-11 3:34

1-Jun-11 3:34

I can not see the error.

Not Active1-Jun-11 3:38

1-Jun-11 3:38

Then we can't help you further

I know the language. I've read a book. - _Madmatt

BobJanova1-Jun-11 4:12

BobJanova

1-Jun-11 4:12

good one

Pete O'Hanlon1-Jun-11 3:25

Pete O'Hanlon

1-Jun-11 3:25

As others have said, your connection is open already. You could wrap the line c.Open() with

if (c.ConnectionState != ConnectionState.Open)
  c.Open();

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

ismail201-Jun-11 3:33

1-Jun-11 3:33

error http://www.imageupload.org/?d=FA9F79481[^]

Not Active1-Jun-11 3:37

1-Jun-11 3:37

We are here to help but you must also put forth some effort. Copy & Paste is not a valid coding technique. You need to understand the objects you are working with. This error is very easily corrected by simply using the Intellisence built in to Visual Studio.

I know the language. I've read a book. - _Madmatt

ismail201-Jun-11 3:44

1-Jun-11 3:44

if (c.State != ConnectionState.Open)
c.Open(); ---- accept that this code ***** but "c.ConnectionState" wrong