use c# threadpool or task to call a function and get return value

I am a newbie to c# threads and need help in implementing a basic task.

I am using below code currently (without using thread) which runs fine.

The concept is to loop through records of a table, pass some table arguments in a function and except a return value and then update the table with the return value.

cmd = new OleDbCommand { Connection = con, CommandText = "Select recid,col_A,col_B from tblData"};

dr = cmd.ExecuteReader();

if (dr.HasRows)

{

cmdRec = new OleDbCommand { Connection = con };

while (dr.Read())

{

sReqResult = DoProcessing(dr["col_A"].ToString(), dr["col_B"].ToString(), dr["PARAM2"].ToString());

sSql = "update tblData set STATUS='" + sReqResult + "' where recid = '" + dr["recid"] + "'";

cmdRec.CommandText = sSql;

cmdRec.ExecuteNonQuery();

}

dr.close();

I want to implement above functionality using threads to speed up the process so that instead of processing the records sequentely, I can run a maximum of 25 threads parallelly. but requirement is to get the return value from the function and update the same in the table.

I have read about threadpool and Tasks (in .net 4.0) but I am not sure how to implement the same. Please guide me with some sample code.

Why dont you use asynchronous call to a method which will create a thread implicitly for each call

class Program
    {
        static int ReadFromTable()
        {
            //your read code here
            return 1;
        }

        //this method will execute on read complete
        static void UpdateTable(IAsyncResult result)
        {
            Del d = (Del)result.AsyncState;
            int IDTOUpdate = d.EndInvoke(result);
            //your update code here
        }
        delegate int Del();
        static void Main(string[] args)
        {
            Del d = new Del(ReadFromTable);
            AsyncCallback callback = new AsyncCallback(UpdateTable);
            IAsyncResult result = d.BeginInvoke(callback, d);
            Console.ReadLine();
        }
    }

1 Reply

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Ehtesham14y ago
Why dont you use asynchronous call to a method which will create a thread implicitly for each call

class Program
    {
        static int ReadFromTable()
        {
            //your read code here
            return 1;
        }

        //this method will execute on read complete
        static void UpdateTable(IAsyncResult result)
        {
            Del d = (Del)result.AsyncState;
            int IDTOUpdate = d.EndInvoke(result);
            //your update code here
        }
        delegate int Del();
        static void Main(string[] args)
        {
            Del d = new Del(ReadFromTable);
            AsyncCallback callback = new AsyncCallback(UpdateTable);
            IAsyncResult result = d.BeginInvoke(callback, d);
            Console.ReadLine();
        }
    }
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