- item
- Handle to the item which represents the item having the property. You can retrieve this parameter by either calling the WiaSession.GetRootItem method to get the device’s root item itself or by enumerating the child items of the device through a call to Leadtools.Wia.WiaSession.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
The property ID for the value being sought, for list of available property IDs see WiaPropertyId.
This parameter is required only if the second parameter "propertyIdName"is null; otherwise you can pass 0 for this parameter.
Visual Basic (Declaration) | |
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Public Function GetPropertyBuffer( _ ByVal item As Object, _ ByVal propertyIdName As String, _ ByVal propertyId As WiaPropertyId _ ) As Stream |
Visual Basic (Usage) | Copy Code |
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Dim instance As WiaSession Dim item As Object Dim propertyIdName As String Dim propertyId As WiaPropertyId Dim value As Stream value = instance.GetPropertyBuffer(item, propertyIdName, propertyId) |
C# | |
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public Stream GetPropertyBuffer( object item, string propertyIdName, WiaPropertyId propertyId ) |
C++/CLI | |
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public: Stream^ GetPropertyBuffer( Object^ item, String^ propertyIdName, WiaPropertyId propertyId ) |
Parameters
- item
- Handle to the item which represents the item having the property. You can retrieve this parameter by either calling the WiaSession.GetRootItem method to get the device’s root item itself or by enumerating the child items of the device through a call to Leadtools.Wia.WiaSession.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
The property ID for the value being sought, for list of available property IDs see WiaPropertyId.
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.Visual Basic | Copy Code |
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Dim myWiaSession As WiaSession Public Sub GetPropertyBufferExample(ByVal parent As IWin32Window) 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 |
C# | Copy Code |
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WiaSession myWiaSession; public void GetPropertyBufferExample(IWin32Window parent) { 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"; } |
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.
Target Platforms: Microsoft .NET Framework 2.0, Windows 2000, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7
Reference
WiaSession ClassWiaSession Members
Startup Method
Shutdown Method
GetRootItem Method
EnumChildItems Method
GetProperties Method
SetProperties Method
SetPropertyBuffer Method
GetPropertyLong Method
SetPropertyLong Method
GetPropertyString Method
SetPropertyString Method
GetPropertyGuid Method
SetPropertyGuid Method
GetPropertySystemTime Method
SetPropertySystemTime Method