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GetPropertyBuffer Method

Summary

Retrieves the buffer of type Stream for any WIA property of type WiaVariableTypes.UI1 or WiaVariableTypes.Vector .

Syntax

C++

public Stream GetPropertyBuffer(  
   object item, 
   string propertyIdName, 
   Leadtools.Wia.WiaPropertyId propertyId 
)

Public Function GetPropertyBuffer( _ 
   ByVal item As Object, _ 
   ByVal propertyIdName As String, _ 
   ByVal propertyId As Leadtools.Wia.WiaPropertyId _ 
) As Stream

public: 
Stream^ GetPropertyBuffer(  
   Object^ item, 
   String^ propertyIdName, 
   Leadtools.Wia.WiaPropertyId propertyId 
)

Parameters

item
Handle to the item which represents the item having the property. You can retrieve this parameter by either calling the GetRootItem method to get the device's root item itself or by enumerating the child items of the device through a call to EnumChildItems method.

propertyIdName
This string should contain the equivalent property Id string for the WIA property ID. Use the see GetPropertyIdString method to get this string for the property ID.

If you passed null for this parameter then the WIA toolkit will use the property ID passed through the third parameter

propertyId**; otherwise this parameters will be used whether or not you passed valid property ID through the propertyId parameter

propertyId*; otherwise this parameters will be used whether or not you passed valid property ID through the propertyId parameter

This parameter is required only if the second parameter "propertyIdName"is null; otherwise you can pass 0 for this parameter.

Return Value

The WIA property buffer value.

Remarks

Any WIA property of type WiaVariableTypes.UI1 or WiaVariableTypes.Vector (for example, WiaPropertyId.CameraItemThumbnail, WiaPropertyId.ScannerDevicePadColor , ...etc) returns a Stream. In order to retrieve this type of buffer you need to call the function GetPropertyBuffer.

For more information, refer to Managing WIA Sources.

Example

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

 codeContainer VBExample hide">Imports Leadtools  Imports Leadtools.Codecs  Imports Leadtools.Wia   Dim myWiaSession As WiaSession  <TestMethod()> _  style="color:Blue;">#If Not LEADTOOLS_V19_OR_LATER Then  Public Sub GetPropertyBufferExample(ByVal parent As IWin32Window)  style="color:Blue;">#Else  Public Sub GetPropertyBufferExample(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  myWiaSession = New WiaSession()  myWiaSession.Startup(WiaVersion.Version1)   Dim res As DialogResult = myWiaSession.SelectDeviceDlg(parent, WiaDeviceType.StreamingVideo, WiaSelectSourceFlags.NoDefault)  If res <> DialogResult.OK Then  MessageBox.Show("Error selecting WIA device.")  myWiaSession.Shutdown()  Return  End If   Dim rootItem As Object = myWiaSession.GetRootItem(Nothing)  If Not rootItem Is Nothing Then  AddHandler myWiaSession.EnumItemsEvent, AddressOf session_EnumItemsEvent2   myWiaSession.EnumChildItems(rootItem)   RemoveHandler myWiaSession.EnumItemsEvent, AddressOf session_EnumItemsEvent2  End If   myWiaSession.Shutdown()  End Sub   Private Sub session_EnumItemsEvent2(ByVal sender As Object, ByVal e As WiaEnumItemsEventArgs)  If Not IsNothing(e.Item) Then  ' Read the camera item thumbnail property.  Dim stream As Stream = myWiaSession.GetPropertyBuffer(e.Item, Nothing, WiaPropertyId.CameraItemThumbnail)   ' Read the camera thumbnail width property.  Dim nWidth As Integer = myWiaSession.GetPropertyLong(e.Item, Nothing, WiaPropertyId.CameraItemThumbWidth)   ' Read the camera thumbnail height property.  Dim nHeight As Integer = myWiaSession.GetPropertyLong(e.Item, Nothing, WiaPropertyId.CameraItemThumbHeight)   Dim userDataLen As Integer = CType(stream.Length, Integer)  Dim userData(userDataLen - 1) As Byte  stream.Read(userData, 0, userDataLen)   Using thumbImage As New RasterImage( _  RasterMemoryFlags.User, _  nWidth, _  nHeight, _  24, _  RasterByteOrder.Bgr, _  RasterViewPerspective.LeftTop, _  Nothing, _  userData, _  userDataLen)  Using codecs As New RasterCodecs()  codecs.Save(thumbImage, Path.Combine(LEAD_VARS.ImagesDir, "WiaThumb.jpg"), RasterImageFormat.Jpeg, 24)  End Using  End Using   myWiaSession.FreeItem(e.Item)  End If  End Sub    Public NotInheritable Class LEAD_VARS  Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"  End Class

codeContainer CSharpExample hide">

using Leadtools;  using Leadtools.Codecs;  using Leadtools.Wia;   WiaSession myWiaSession;  [TestMethod]  style="color:Blue;">#if !LEADTOOLS_V19_OR_LATER  public void GetPropertyBufferExample(IWin32Window parent)  style="color:Blue;">#else  public void GetPropertyBufferExample(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;  }  myWiaSession = new WiaSession();  myWiaSession.Startup(WiaVersion.Version1);   DialogResult res = myWiaSession.SelectDeviceDlg(parent, WiaDeviceType.StreamingVideo, WiaSelectSourceFlags.NoDefault);  if (res != DialogResult.OK)  {  MessageBox.Show("Error selecting WIA device.");  myWiaSession.Shutdown();  return;  }   object rootItem = myWiaSession.GetRootItem(null);  if (rootItem != null)  {  myWiaSession.EnumItemsEvent += new EventHandler<WiaEnumItemsEventArgs>(wiaSession_EnumItemsEvent2);   myWiaSession.EnumChildItems(rootItem);   myWiaSession.EnumItemsEvent -= new EventHandler<WiaEnumItemsEventArgs>(wiaSession_EnumItemsEvent2);  }   myWiaSession.Shutdown();  }   void wiaSession_EnumItemsEvent2(object sender, WiaEnumItemsEventArgs e)  {  if(e.Item != null)  {  // Read the camera item thumbnail property.  Stream stream = myWiaSession.GetPropertyBuffer(e.Item, null, WiaPropertyId.CameraItemThumbnail);   // Read the camera thumbnail width property.  int nWidth = myWiaSession.GetPropertyLong(e.Item, null, WiaPropertyId.CameraItemThumbWidth);   // Read the camera thumbnail height property.  int nHeight = myWiaSession.GetPropertyLong(e.Item, null, WiaPropertyId.CameraItemThumbHeight);   int userDataLen = (int)stream.Length;  byte[] userData = new byte[userDataLen];  stream.Read(userData, 0, userDataLen);   using(RasterImage thumbImage = new RasterImage(  RasterMemoryFlags.User,  nWidth,  nHeight,  24,  RasterByteOrder.Bgr,  RasterViewPerspective.LeftTop,  null,  userData,  userDataLen))  {  using(RasterCodecs codecs = new RasterCodecs())  {  codecs.Save(thumbImage, Path.Combine(LEAD_VARS.ImagesDir,  "WiaThumb.jpg"), RasterImageFormat.Jpeg, 24);  }  }   myWiaSession.FreeItem(e.Item);  }  }    static class LEAD_VARS  {  public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";  }