←Select platform

IsVideoPreviewAvailable Method

Summary

Determines whether there is an available video preview.

Syntax

C++

public bool IsVideoPreviewAvailable()

Public Function IsVideoPreviewAvailable() As Boolean

public: 
bool IsVideoPreviewAvailable();

Return Value

true if the video preview is started; otherwise, false.

Remarks

This function is used to determine whether the video preview has started. Start the video preview by calling the WiaSession.StartVideoPreview method.

Example

                                                                                              
id="CSharpExampleTab" onclick="$.selectCodeContainer(this)">C#
 id="VBExampleTab" onclick="$.selectCodeContainer(this)">VB

 codeContainer VBExample hide">Imports Leadtools  Imports Leadtools.Codecs  Imports Leadtools.Wia   <TestMethod()> _  style="color:Blue;">#If Not LEADTOOLS_V19_OR_LATER Then  Public Sub IsVideoPreviewAvailableExample(ByVal parent As IWin32Window)  style="color:Blue;">#Else  Public Sub IsVideoPreviewAvailableExample(ByVal parent As IntPtr)  style="color:Blue;">#End If ' #If LEADTOOLS_V19_OR_LATER Then  If (Not wiaSession.IsAvailable(WiaVersion.Version1)) Then  MessageBox.Show("WIA version 1.0 not installed.")  Return  End If  Dim session As WiaSession = New WiaSession()  session.Startup(WiaVersion.Version1)   Dim res As DialogResult = session.SelectDeviceDlg(parent, WiaDeviceType.StreamingVideo, WiaSelectSourceFlags.NoDefault)  If res <> DialogResult.OK Then  MessageBox.Show("Error selecting WIA device.")  session.Shutdown()  Return  End If   ' start the video preview  wiaSession.StartVideoPreview(parent, False)   ' determine whether a video preview is available  Dim available As Boolean = wiaSession.IsVideoPreviewAvailable()  If (Not available) Then  MessageBox.Show("No streaming video available.")  wiaSession.EndVideoPreview()  wiaSession.Shutdown()  Return  End If   'Resize the video preview area to fit the parent window.  'I am calling this resize function here only for demonstration purposes, but you  'should call it in your window resize event.  wiaSession.ResizeVideoPreview(True)   ' acquire an image from the video source.  Dim takenPictureFileName As String = wiaSession.AcquireImageFromVideo()   Dim strMsg As String = String.Format("Acquired image was saved to the following path:\n{0}", takenPictureFileName)  MessageBox.Show(strMsg)   wiaSession.EndVideoPreview()  session.Shutdown()  End Sub

codeContainer CSharpExample hide">

using Leadtools;  using Leadtools.Codecs;  using Leadtools.Wia;   [TestMethod]  style="color:Blue;">#if !LEADTOOLS_V19_OR_LATER  public void IsVideoPreviewAvailableExample(IWin32Window parent)  style="color:Blue;">#else  public void IsVideoPreviewAvailableExample(IntPtr parent)  style="color:Blue;">#endif // #if !LEADTOOLS_V19_OR_LATER  {  if (!WiaSession.IsAvailable(WiaVersion.Version1))  {  MessageBox.Show("WIA version 1.0 not installed.");  return;  }  WiaSession wiaSession = new WiaSession();  wiaSession.Startup(WiaVersion.Version1);   DialogResult res = wiaSession.SelectDeviceDlg(parent, WiaDeviceType.StreamingVideo, WiaSelectSourceFlags.NoDefault);  if (res != DialogResult.OK)  {  MessageBox.Show("Error selecting WIA device.");  wiaSession.Shutdown();  return;  }   // start the video preview  wiaSession.StartVideoPreview(parent, false);   // determine whether a video preview is available  bool available = wiaSession.IsVideoPreviewAvailable();  if(!available)  {  MessageBox.Show("No streaming video available.");  wiaSession.EndVideoPreview();  wiaSession.Shutdown();  return;  }   // Resize the video preview area to fit the parent window.  // I am calling this resize function here only for demonstration purposes, but you  // should call it in your window resize event.  wiaSession.ResizeVideoPreview(true);   // acquire an image from the video source.  string takenPictureFileName = wiaSession.AcquireImageFromVideo();   string strMsg = String.Format("Acquired image was saved to the following path:\n{0}", takenPictureFileName);  MessageBox.Show(strMsg);   wiaSession.EndVideoPreview();  wiaSession.Shutdown();  }