Use WIA to retrieve images from scanner, digital camera or webcam using VB.NET and C#.

Imports System.Drawing
Imports System.Runtime.InteropServices
Imports WIALib
Imports System.IO
 
Public Class ImageRetriever
 
    Public Function RetriveImages(ByVal selectionMode As ImageSelectionMode) As List(Of Bitmap)
 
        Dim comObjects As New List(Of Object)
 
        'Create WIA COM objects
 
        'Manager
        Dim manager As WiaClass = Nothing
        comObjects.Add(manager)
 
        'Devices collection
        Dim devices As CollectionClass = Nothing
        comObjects.Add(devices)
 
        'Root device
        Dim rootDevice As ItemClass = Nothing
        comObjects.Add(rootDevice)
 
        'Collection
        Dim pictures As CollectionClass = Nothing
        comObjects.Add(pictures)
 
        'Image
        Dim pictureItem As ItemClass = Nothing
        comObjects.Add(pictureItem)
 
        manager = New WiaClass()
 
        devices = TryCast(manager.Devices, CollectionClass)
 
        'Retrieve all devices
        If (devices Is Nothing) OrElse (devices.Count = 0) Then
            DisposeComObjects(comObjects)
            Throw New AcquisitionException("No devices found.")
        End If
 
        Dim UISelection As Object = System.Reflection.Missing.Value
 
        'WIA dialog, allows user to select a device
        rootDevice = DirectCast(manager.Create(UISelection), ItemClass)
 
        If rootDevice Is Nothing Then
            Throw New AcquisitionException("No device selected.")
        End If
 
        'WIA dialog, allows user to select a picture.
 
        Dim flag As WiaFlag = WiaFlag.SingleImage
        If selectionMode = ImageSelectionMode.Multiple Then flag = WiaFlag.UseCommonUI
 
        pictures = TryCast(rootDevice.GetItemsFromUI(flag, WiaIntent.ImageTypeColor), CollectionClass)
        If pictures Is Nothing Then
            DisposeComObjects(comObjects)
            Throw New AcquisitionException("No pictures selected.")
        End If
 
        Dim bitmapList As New List(Of Bitmap)
 
        For Each picture As Object In pictures
 
            Dim filePath As String = Path.GetTempFileName
            pictureItem = DirectCast(Marshal.CreateWrapperOfType(picture, GetType(ItemClass)), ItemClass)
            pictureItem.Transfer(filePath, False)
 
            bitmapList.Add(Image.FromFile(filePath))
 
            'Release COM object
            Marshal.ReleaseComObject(picture)
 
        Next
 
        Return bitmapList
 
        DisposeComObjects(comObjects)
 
    End Function
 
    Private Sub DisposeComObjects(ByVal objects As List(Of Object))
        For Each comObject In objects
            If comObject IsNot Nothing Then
                Marshal.ReleaseComObject(comObject)
            End If
        Next
    End Sub
 
End Class
 
Public Class AcquisitionException
    Inherits Exception
 
    Public Sub New(ByVal message As String)
        MyBase.New(message)
    End Sub
 
End Class
 
Public Enum ImageSelectionMode
    One = 0
    Multiple = 1
End Enum

 
using System.Drawing;
using System.Runtime.InteropServices;
using WIALib;
using System.IO;
 
 
public class ImageRetriever
{
 
 
    public List<Bitmap> RetriveImages(ImageSelectionMode selectionMode)
    {
 
        List<object> comObjects = new List<object>();
 
        //Create WIA COM objects
 
        //Manager
        WiaClass manager = null;
        comObjects.Add(manager);
 
        //Devices collection
        CollectionClass devices = null;
        comObjects.Add(devices);
 
        //Root device
        ItemClass rootDevice = null;
        comObjects.Add(rootDevice);
 
        //Collection
        CollectionClass pictures = null;
        comObjects.Add(pictures);
 
        //Image
        ItemClass pictureItem = null;
        comObjects.Add(pictureItem);
 
        manager = new WiaClass();
 
        devices = manager.Devices as CollectionClass;
 
 
        //Retrieve all devices
        if ((devices == null) || (devices.Count == 0)) {
            DisposeComObjects(comObjects);
            throw new AcquisitionException("No devices found.");
        }
 
 
        object UISelection = System.Reflection.Missing.Value;
 
 
        //WIA dialog, allows user to select a device
        rootDevice = (ItemClass)manager.Create(UISelection);
 
 
 
        if (rootDevice == null) {
            throw new AcquisitionException("No device selected.");
        }
 
        //WIA dialog, allows user to select a picture.
 
        WiaFlag flag = WiaFlag.SingleImage;
        if (selectionMode == ImageSelectionMode.Multiple) flag = WiaFlag.UseCommonUI; 
 
 
        pictures = rootDevice.GetItemsFromUI(flag, WiaIntent.ImageTypeColor) as CollectionClass;
        if (pictures == null) {
            DisposeComObjects(comObjects);
            throw new AcquisitionException("No pictures selected.");
        }
 
        List<Bitmap> bitmapList = new List<Bitmap>();
 
        foreach (object picture in pictures) {
 
            string filePath = Path.GetTempFileName;
            pictureItem = (ItemClass)Marshal.CreateWrapperOfType(picture, typeof(ItemClass));
            pictureItem.Transfer(filePath, false);
 
            bitmapList.Add(Image.FromFile(filePath));
 
            //Release COM object
 
            Marshal.ReleaseComObject(picture);
        }
 
 
        return bitmapList;
 
 
 
        DisposeComObjects(comObjects);
    }
 
    private void DisposeComObjects(List<object> objects)
    {
        foreach (var comObject in objects) {
            if (comObject != null) {
                Marshal.ReleaseComObject(comObject);
            }
        }
    }
 
}
 
 
public class AcquisitionException : Exception
{
 
    public AcquisitionException(string message) : base(message)
    {
    }
 
}
 
public enum ImageSelectionMode
{
    One = 0,
    Multiple = 1
}