EndExecuteReader Method (DB2Command)

In This Topic

Ends an asynchronous invocation of the ExecuteReader method.

Syntax

Visual Basic
C#

'Declaration
 
Public Shadows Function EndExecuteReader( _
   ByVal result As IAsyncResult _
) As DB2DataReader

public new DB2DataReader EndExecuteReader( 
   IAsyncResult result
)

Parameters

result: The System.IAsyncResult returned from BeginExecuteReader.

Return Value

A DB2DataReader object.

Remarks

The function ends an asynchronous execution of a query that is started with BeginExecuteReader. A pair of asynchronous functions (BeginExecuteReader and EndExecuteReader) can be used instead of the synchronous function ExecuteReader to gain more performance and flexibility in your application.

Refer to "Asynchronous Query Execution" article for detailed information.

Example

In the example below an easiest way of executing an asynchronous operation is shown. First, all components are set up and a connection is opened. Second, a data retrieval operation is started. The operation state (done or in progress) is checked and a report is written to the console. At last query results are sent to DB2DataReader and rendered to the console.

csharp

Public void Async_Exec(DB2Connection db2Connection)
{
  DB2Command db2Command = new DB2Command("SELECT * FROM Dept",db2Connection);
  Console.WriteLine("Starting asynchronous retrieval of data...");
  db2Connection.Open();
  IAsyncResult cres = db2Command.BeginExecuteReader(null,null,CommandBehavior.Default);
  if (cres.IsCompleted)
    Console.WriteLine("Completed.");
  else
    Console.WriteLine("Have to wait for operation to complete...");
  DB2DataReader db2Reader = db2Command.EndExecuteReader(cres);
  try
  {
    while (db2Reader.Read())
    {
      Console.WriteLine(db2Reader.GetInt32(0) + " " + db2Reader.GetString(1) + " " + db2Reader.GetString(2));
    }
  }
  finally
  {
    db2Reader.Close();
    db2Connection.Close();
  }
}

Visual Basic

Public Sub Async_Exec(ByVal db2Connection As DB2Connection)
  Dim db2Command As New DB2Command("SELECT * FROM Dept", db2Connection)
  Console.WriteLine("Starting asynchronous retrieval of data...")
  db2Connection.Open()
  Dim cres As IAsyncResult = db2Command.BeginExecuteReader(Nothing, Nothing, CommandBehavior.Default)
  If cres.IsCompleted Then
    Console.WriteLine("Completed.")
  Else
    Console.WriteLine("Have to wait for operation to complete...")
  End If
  Dim db2Reader As DB2DataReader = db2Command.EndExecuteReader(cres)
  Try
    While db2Reader.Read()
      Console.WriteLine(String.Concat(db2Reader.GetInt32(0), " ", db2Reader.GetString(1), " ", db2Reader.GetString(2)))
    End While
  Finally
    db2Reader.Close()
    db2Connection.Close()
  End Try
End Sub

Reference

DB2Command Class
DB2Command Members
BeginExecuteReader Method
ExecuteReader Method
EndExecuteNonQuery Method

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