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AcquireToFile Method

Summary

Acquires one or more images from a WIA source directly to file(s).

Syntax

C#
VB
C++
public DialogResult AcquireToFile( 
   IntPtr owner, 
   object item, 
   WiaAcquireFlags flags 
) 
  
Public Function AcquireToFile( _ 
   ByVal owner As IntPtr, _ 
   ByVal item As Object, _ 
   ByVal flags As Leadtools.Wia.WiaAcquireFlags _ 
) As DialogResult 
public: 
DialogResult AcquireToFile(  
   IntPtr owner, 
   Object^ item, 
   Leadtools.Wia.WiaAcquireFlags flags 
)  

Parameters

owner
Window handle of your application window.

item
This parameter is only used if you are acquiring from a scanner device and the ShowUserInterface flag is NOT set. Use this parameter to specify the scanner's paper source (Feeder or Flatbed).

This flag is optional if you are using WIA 1.0 since you can change the paper source by changing the WiaPropertyId.ScannerDeviceDocumentHandlingSelect property value for the root item or by enumerating the available scanner items and passing the desired scanner item.

If you are using WIA 2.0, either enumerate the available scanner items and pass the desired scanner item; or pass null (Nothing in VB), in which case the enumeration will be performed internally and the first enumerated item will be used as the source item.

flags
Flag that determines certain actions of the WIA image acquisition selection dialog box. Possible values are:

Value Meaning
WiaAcquireFlags.None Default behavior for the device image acquisition dialog box.
WiaAcquireFlags.SingleImage Restrict image selection to a single image in the device image acquisition dialog box. This flag is not available if you are using WIA version 2.0.
WiaAcquireFlags.ShowUserInterface Show the manufacturer's image acquisition dialog box.
WiaAcquireFlags.UseCommonUI Use the system user interface (UI), if available, rather than the vendor-supplied UI. If the system UI is not available, the vendor UI is used.

Return Value

One of the DialogResult values. If an error occurs, an exception is thrown.

Remarks

This function will acquire single or multiple images from the selected WIA device and save them directly to file(s).

Make sure to call WiaSession.Startup and then call any of the WiaSession.SelectDeviceDlg or WiaSession.SelectDevice functions before calling this function.

Change the AcquireOptions property members before calling this method to control the saved filenames and paths, along with other options while acquiring from the WIA source.

When performing file transfer it is optional to add the AcquireEvent event, since the event will only provide you with the saved file path and name and the percent completion of the file saving process.

Two properties within the WiaSession class will become available when using this function:

  • FilesCount - contains the number of files being saved.
  • FilesPaths - a collection that contains the saved file paths and filenames.

To cancel the acquire operation, add the AcquireEvent event and set the Cancel member of the WiaAcquireEventArgs to true.

Note: If the ShowUserInterface flag is set for any of the acquire methods, then be aware that some of the previously set/changed user properties (using any of the SetPropertyXxx or SetProperties methods) will be overwritten by the Microsoft's image acquisition dialog box. Microsoft's image acquisition dialog box sets its own initialization properties like the current intent (image type), selected area (left, top, width and height), paper source and duplex mode, ...etc. To suppress the manufacturer's image acquisition dialog and acquire directly from the specified source item through the item parameter using the values set through the SetPropertyXxx and SetProperties methods, do not set the ShowUserInterface flag.
Note: While running a Win32 version application that calls this function on Windows VISTA 64-Bit we have noticed that the FilesCount and FilesPaths properties will not be updated with the required information. This is a known limitation of Microsoft's WIA toolkit.
Note: If you are using WIA 2.0 while the ShowUserInterface flag is set then it is not necessary to add the AcquireEvent event. Microsoft's WIA 2.0 Acquire dialog does not provide an event but performs all of the processing and returns with the number of files that were saved along with their paths through the FilesCount and FilesPaths properties.

For more information, refer to How to Acquire from the WIA Source.

Example

C#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Wia; 
 
public void AcquireToFileExample(IntPtr parent) 
{ 
   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.Default, WiaSelectSourceFlags.NoDefault); 
   if (res != DialogResult.OK) 
   { 
      MessageBox.Show("Error selecting WIA device."); 
      wiaSession.Shutdown(); 
      return; 
   } 
 
   // Initialize and fill the required fields from the WiaAcquireOptions structure 
   WiaAcquireOptions wiaAcquireOptions = WiaAcquireOptions.Empty; 
   wiaAcquireOptions.FileName = Path.Combine(LEAD_VARS.ImagesDir, "WiaTest.bmp"); 
   wiaAcquireOptions.OverwriteExisting = true; 
   wiaAcquireOptions.Append = false; 
   wiaAcquireOptions.SaveToOneFile = false; 
   wiaSession.AcquireOptions = wiaAcquireOptions; 
 
   wiaSession.AcquireFileEvent += new EventHandler<WiaAcquireFileEventArgs>(wiaSession_AcquireFileEvent); 
 
   wiaSession.AcquireToFile(parent, null, WiaAcquireFlags.ShowUserInterface | WiaAcquireFlags.UseCommonUI); 
 
   // Display a listing of all paths and filenames for the saved files(s). 
   if (wiaSession.FilesCount > 0) 
   { 
      string strMsg = "Acquired page(s) were saved to:\n\n"; 
      for (int i = 0; i < wiaSession.FilesCount; i++) 
      { 
         string strTemp = string.Format("{0}\n", wiaSession.FilesPaths[i]); 
         strMsg += strTemp; 
      } 
      MessageBox.Show(strMsg); 
   } 
 
   wiaSession.AcquireFileEvent -= new EventHandler<WiaAcquireFileEventArgs>(wiaSession_AcquireFileEvent); 
   wiaSession.Shutdown(); 
} 
 
public void wiaSession_AcquireFileEvent(object sender, WiaAcquireFileEventArgs e) 
{ 
   Console.WriteLine(e.Percent); 
} 
 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Wia 
 
<TestMethod()> _ 
Public Sub AcquireToFileExample(ByVal parent As IntPtr) 
   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.Default, WiaSelectSourceFlags.NoDefault) 
   If res <> DialogResult.OK Then 
      MessageBox.Show("Error selecting WIA device.") 
      session.Shutdown() 
      Return 
   End If 
 
   ' Initialize and fill the required fields from the WiaAcquireOptions structure 
   Dim wiaAcquireOptions As WiaAcquireOptions = wiaAcquireOptions.Empty 
   wiaAcquireOptions.FileName = Path.Combine(LEAD_VARS.ImagesDir, "WiaTest.bmp") 
   wiaAcquireOptions.OverwriteExisting = True 
   wiaAcquireOptions.Append = False 
   wiaAcquireOptions.SaveToOneFile = False 
   session.AcquireOptions = wiaAcquireOptions 
 
   AddHandler session.AcquireFileEvent, AddressOf session_AcquireFileEvent 
 
   session.AcquireToFile(parent, Nothing, WiaAcquireFlags.ShowUserInterface Or WiaAcquireFlags.UseCommonUI) 
 
   ' Display listing of all paths and filenames for the saved files(s). 
   If session.FilesCount > 0 Then 
      Dim strMsg As String = "Acquired page(s) were saved to:" & Constants.vbLf + Constants.vbLf 
      Dim i As Integer = 0 
      Do While i < session.FilesCount 
         Dim strTemp As String = String.Format("{0}" & Constants.vbLf, session.FilesPaths(i)) 
         strMsg &= strTemp 
         i += 1 
      Loop 
      MessageBox.Show(strMsg) 
   End If 
 
   RemoveHandler session.AcquireFileEvent, AddressOf session_AcquireFileEvent 
   session.Shutdown() 
End Sub 
 
Public Sub session_AcquireFileEvent(ByVal sender As Object, ByVal e As WiaAcquireFileEventArgs) 
   Console.WriteLine(e.Percent) 
End Sub 
 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class 

Requirements

Target Platforms

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