Related Ado.net For MySql

Kedar Pawgi

Hi i have just shifted from ADODB to Ado.net for MySql. I am new to this system.

After going thru the forums i have defined the connection, adapter, reader , command.

I defined in all this in a class, i am calling that class in every form so that i dont have to created the same for every form. I have written things like following

public MySqlConnection conn;
public MySqlCommand cmd;
public MySqlDataReader dr;
public MySqlDataAdapter da;

the DB is conneced through DSN. Here everything is working fine. But while working i got error message like

"There is already an open DataReader associated with this Command which must be closed"

So i searched on forum, but i being new to this things , i request you to please kindly suggest how i can close connect, open connected and how i should declear variables in a class.

I will be very thankful for this in advance. i am developing a customized software , so asap help is very much appriciated.

Thank you

5 Replies

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Ankit Sharma9y ago
Accepted answer
Hi Kedar,

Make sure you have used

reader.Close();
reader.Dispose();
connection.Close();

at the end of you method

https://www.codeproject.com/Questions/616154/There-is-already-an-open-DataReader-associated-wit

you can get a sample code here also

https://www.aspsnippets.com/Articles/Using-MySQL-database-in-ASPNet-Tutorial-with-example.aspx
Kedar Pawgi9y ago
Hi Gautam and Ankit...Actually i figured it out. I was not closing the reader , i was just closing the connection. When i properly checked and opened and closed the connected as suggest by Ankit like
reader.Close();
reader.Dispose();
connection.Close();
then i re opened the connection. It worked perfectly. Actually both of u given correct ans but i m sorry i will have to accept one answer so i am accepted Ankits ans, sorry Gautam for this.

Thanks u guys made my day. TC thanks
Ankit Sharma9y ago
Hi kedar,

i think your issue is similar to one mentioned here

https://stackoverflow.com/questions/18475195/error-there-is-already-an-open-datareader-associated-with-this-command-which-mu
Kedar Pawgi9y ago
Thanks for your reply Gautam and Ankit.
Actually my issue is i have totally 3 form out of which i doing operation of INSERT in two form and One of Select. But on 3rd form , i am doing 2 opetations of SELECT, i would like to know , does it is giving that error as i am doing two SELECT operations.
On first two form its working perfectly.

So please let me know how i use "c.dr" for two different SELECT statements.
Gautam Parmar9y ago
Once you finish use of DataReader close command with below code.
SqlDataReader sdr = cmd.ExecuteReader();

//Your Code of Use Data Reader

//Close Data Reader
sdr.Close();