KeyDownEventHandler Delegate

C#
Visual Basic
Objective-C
Java
C++

public delegate void KeyDownEventHandler( 
   object sender,
   KeyDownEventArgs e
)

'Declaration

Public Delegate Sub KeyDownEventHandler( _
   ByVal sender As Object, _
   ByVal e As KeyDownEventArgs _
)

'Usage

Dim instance As New KeyDownEventHandler(AddressOf HandlerMethod)

public delegate void KeyDownEventHandler( 
   Object^ sender,
   KeyDownEventArgs^ e
)

Parameters

sender: The source of the event.
e: A KeyDownEventArgs object that contains the event data.

Represents the method that will handle an event that has received KeyDownEventArgs data. When the KeyDownEvent event is raised in a toolkit object, any subscribed event handlers in your code will be called. See the Microsoft documentation on .NET Events and Delegates for more information about .NET delegates and events.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Multimedia
Imports LeadtoolsMultimediaExamples.Fixtures

Public _result As Boolean = False
Public _exit As Boolean = False
Public _form As CaptureCtrlForm = New CaptureCtrlForm()
Public Sub KeyPressesExample()
   Dim capturectrl As CaptureCtrl = _form.CaptureCtrl
   Dim outFile As String = Path.Combine(LEAD_VARS.MediaDir, "CaptureCtrl_KeyPressesExample.avi")

   Try
      ' set a video device, use the name of your device here
      If capturectrl.VideoDevices("Analog") Is Nothing Then
         Throw New Exception("No Analog capture device available")
      End If

      capturectrl.VideoDevices("Analog").Selected = True

      ' select the MPEG4 video compressor
      capturectrl.VideoCompressors.Mpeg4.Selected = True

      ' set an audio device, use the name of your device here
      capturectrl.AudioDevices("USB").Selected = True

      ' enable preview
      capturectrl.Preview = True

      ' enable CC
      capturectrl.ClosedCaptioning = True

      ' set the target output file
      capturectrl.TargetFile = outFile

      ' subscribe to the key events
      AddHandler capturectrl.KeyDown, AddressOf KeyDown_Helper
      AddHandler capturectrl.KeyUp, AddressOf KeyUp_Helper
      AddHandler capturectrl.KeyPress, AddressOf KeyPress_Helper

      ' capture it now!
      capturectrl.StartCapture(CaptureMode.AutoFramesAndAudio)
   Catch e1 As Exception
      _result = False
   End Try

   ' we'll loop on the state and pump messages for this example.
   ' but you should not need to if running from a Windows Forms application.
   Do While _exit = False
      Application.DoEvents()
   Loop

   ' clean up event handlers
   RemoveHandler capturectrl.KeyDown, AddressOf KeyDown_Helper
   RemoveHandler capturectrl.KeyUp, AddressOf KeyUp_Helper
   RemoveHandler capturectrl.KeyPress, AddressOf KeyPress_Helper
End Sub

Private Sub KeyPress_Helper(ByVal sender As Object, ByVal e As Leadtools.Multimedia.KeyPressEventArgs)
   Select Case e.keyAscii
      Case CShort("p")
         ' toggle preview mode
         _form.CaptureCtrl.TogglePreview()
      Case CShort("f")
         ' toggle full screen mode
         _form.CaptureCtrl.ToggleFullScreenMode()
      Case CShort("c")
         ' toggle closed captioning
         _form.CaptureCtrl.ToggleClosedCaptioning()
      Case CShort("s")
         ' stop the capture and exit
         _form.CaptureCtrl.StopCapture()
         _exit = True
   End Select

   ' set result
   _result = True
End Sub

Private Sub KeyUp_Helper(ByVal sender As Object, ByVal e As KeyUpEventArgs)
   ' set result
   _result = True
End Sub

Public Sub KeyDown_Helper(ByVal sender As Object, ByVal e As KeyDownEventArgs)
   ' set result
   _result = True
End Sub

Public NotInheritable Class LEAD_VARS
Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 19\Media"
End Class

using Leadtools;
using Leadtools.Multimedia;
using LeadtoolsMultimediaExamples.Fixtures;

public bool _result = false;
public bool _exit = false;
public CaptureCtrlForm _form = new CaptureCtrlForm();
public void KeyPressesExample()
{
   CaptureCtrl capturectrl = _form.CaptureCtrl;
   string outFile = Path.Combine(LEAD_VARS.MediaDir,"CaptureCtrl_KeyPressesExample.avi");

   try
   {
      // set a video device, use the name of your device here
      if (capturectrl.VideoDevices["Analog"] == null)
         throw new Exception("No Analog capture device available");

      capturectrl.VideoDevices["Analog"].Selected = true;

      // select the MPEG4 video compressor
      capturectrl.VideoCompressors.Mpeg4.Selected = true;

      // set an audio device, use the name of your device here
      capturectrl.AudioDevices["USB"].Selected = true;

      // enable preview
      capturectrl.Preview = true;

      // enable CC
      capturectrl.ClosedCaptioning = true;

      // set the target output file
      capturectrl.TargetFile = outFile;

      // subscribe to the key events
      capturectrl.KeyDown += KeyDown_Helper;
      capturectrl.KeyUp += KeyUp_Helper;
      capturectrl.KeyPress += KeyPress_Helper;

      // capture it now!
      capturectrl.StartCapture(CaptureMode.AutoFramesAndAudio);
   }
   catch (Exception)
   {
      _result = false;
   }

   // we'll loop on the state and pump messages for this example.
   // but you should not need to if running from a Windows Forms application.
   while (_exit == false)
      Application.DoEvents();

   // clean up event handlers
   capturectrl.KeyDown -= KeyDown_Helper;
   capturectrl.KeyUp -= KeyUp_Helper;
   capturectrl.KeyPress -= KeyPress_Helper;
}

void KeyPress_Helper(object sender, Leadtools.Multimedia.KeyPressEventArgs e)
{
   switch ((char)e.keyAscii)
   {
      case 'p':
         // toggle preview mode
         _form.CaptureCtrl.TogglePreview();
         break;
      case 'f':
         // toggle full screen mode
         _form.CaptureCtrl.ToggleFullScreenMode();
         break;
      case 'c':
         // toggle closed captioning
         _form.CaptureCtrl.ToggleClosedCaptioning();
         break;
      case 's':
         // stop the capture and exit
         _form.CaptureCtrl.StopCapture();
         _exit = true;
         break;
   }

   // set result
   _result = true;
}

void KeyUp_Helper(object sender, KeyUpEventArgs e)
{
   // set result
   _result = true;
}

public void KeyDown_Helper(object sender, KeyDownEventArgs e)
{
   // set result
   _result = true;
}

static class LEAD_VARS
{
public const string MediaDir = @"C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 19\Media";
}

Target Platforms

Reference

KeyDownEventHandler Members
Leadtools.Multimedia Namespace