EndExecuteReader Method (SQLiteCommand)

In This Topic

Syntax
Remarks
Example
See Also

Ends an asynchronous invocation of the ExecuteReader method.

Syntax

Visual Basic
C#

public new SQLiteDataReader EndExecuteReader( 
   IAsyncResult result
)

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

Parameters

result: The System.IAsyncResult returned from BeginExecuteReader.

Return Value

A SQLiteDataReader 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 SQLiteDataReader and rendered to the console.

csharp

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

Visual Basic

Public Sub Async_Exec(ByVal sqConnection As SQLiteConnection)
  Dim sqCommand As New SQLiteCommand("SELECT * FROM Dept", sqConnection)
  Console.WriteLine("Starting asynchronous retrieval of data...")
  sqConnection.Open()
  Dim cres As IAsyncResult = sqCommand.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 sqReader As SQLiteDataReader = sqCommand.EndExecuteReader(cres)
  Try
    While sqReader.Read()
      Console.WriteLine(String.Concat(sqReader.GetInt32(0), " ", sqReader.GetString(1), " ", sqReader.GetString(2)))
    End While
  Finally
    sqReader.Close()
    sqConnection.Close()
  End Try
End Sub

Reference

SQLiteCommand Class
SQLiteCommand Members
BeginExecuteReader Method
ExecuteReader Method
EndExecuteNonQuery Method

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