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c# database (access) return results from a function

Posted on 2013-01-18
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Last Modified: 2013-01-18
Hi

I am new to c# and have (through help on this website ;o) ) created a function which connects to a database and performs an sql query.

this is fine for updates and inserts, but when I need to return data it doesn't work like I want it, I get errors because the code in the function is closing the connection, so the returned data 'expires'

here is the code:


public OleDbDataReader data_sql(string strsql)
        {
            OleDbConnection connection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\mydata.mdb");
            connection.Open();
            OleDbCommand cmd = new OleDbCommand(strsql);
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.Connection = connection;
            OleDbDataReader reader = default(OleDbDataReader);
            reader = cmd.ExecuteReader();
            connection.Close();

            return reader;

        }

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how can I get the returned data available outside of the function?

Cheers

CD
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Comment
Question by:cycledude
  • 2
4 Comments
 
LVL 4

Expert Comment

by:DanielSV
ID: 38792129
Hi,

You need to read out the data before you close the connection.

After you do ExecuteReader();, do something like.

while(reader.Read())
{
// Pull out the data you want here.
}

See http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executereader(v=vs.71).aspx for an example.
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LVL 21

Accepted Solution

by:
Dale Burrell earned 500 total points
ID: 38792135
Remove the line connection.Close(). And change ExecuteReader to be ExecuteReader(CommandBehavior.CloseConnection).
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Author Comment

by:cycledude
ID: 38792149
Thanks

I have changed the function slightly to return the result, then close the connection... that appears to be working.

have also tried dale_burrell's advice, and that works too.

Thanks ;o)
0
 

Author Closing Comment

by:cycledude
ID: 38792153
many thanks
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