C#

static EmitHelper()
{
    try
    {
        var dynam = new DynamicMethod(string.Empty, typeof(int), new Type[] { typeof(int) }, Module, true);
        ILGenerator il = dynam.GetILGenerator();
        il.Emit(OpCodes.Ldarg_0);
        il.Emit(OpCodes.Ldarg_0);
        il.Emit(OpCodes.Mul);
        il.Emit(OpCodes.Ret);
        var sq = (Func<int, int>)dynam.CreateDelegate(typeof(Func<int, int>));
        if (sq(2) == 4)
        {
            SupportsEmit = true;
        }
    }
    catch { }
}
public static bool SupportsEmit { get; private set; }

try
                {

                    object[] items = await Task.Run<object[]>(() =>
                    {

                        var deviceManager = new DeviceManager();
                        List<object> result = new List<object>();

                       
                        for (int i = 1; i <= deviceManager.DeviceInfos.Count; i++) // Loop Through the get List Of Devices.
                        {
                            if (deviceManager.DeviceInfos[i].Type != WiaDeviceType.ScannerDeviceType) // Skip device If it is not a scanner
                            {
                                continue;
                            }
                            //new
                            result.Add(deviceManager.DeviceInfos[i].Properties["Name"].get_Value());
                        }
                        return result.ToArray();
                       

                    });

                    foreach (var item in items)
                    {
                        lstListOfScanner.Items.Add(item);
                    }
                
            }
                catch (COMException ex)
                {
                    MessageBox.Show(ex.Message);
                }

            int n = 1;
            bool continueRunning2 = true;
            try
            {
                await Task.Run(() =>
                {
                    var deviceManager = new DeviceManager();

                    DeviceInfo AvailableScanner = null;

                    for (int i = 1; i <= deviceManager.DeviceInfos.Count; i++)
                    {
                        if (deviceManager.DeviceInfos[i].Type != WiaDeviceType.ScannerDeviceType) // Skip device If it is not a scanner
                        {
                            continue;
                        }

                        AvailableScanner = deviceManager.DeviceInfos[i];
                        break;
                    }
                    /*
                     if (AvailableScanner == null)
                     {
                         return;
                     }
                     */
                    var device = AvailableScanner.Connect();
                    while (AvailableScanner != null)
                    {

                        var ScanerItem = device.Items[1];
                        var imgFile = (ImageFile)ScanerItem.Transfer();

                        var data = (byte[])imgFile.FileData.get_BinaryData();
                        var bitmap = GetBitmapFromRawData(imgFile.Width, imgFile.Height, data);

                        var Path = @"C:\Users\...\Desktop\test\" + n + ".jpg"; // save the image in some path with filename.
                        n++;
                        bitmap.Save(Path, System.Drawing.Imaging.ImageFormat.Jpeg);
                    }
                });
            }
            catch (COMException ex)
            {

                MessageBox.Show(ex.Message);
            }

catch (COMException ex)
{
uint errorCode = (uint)ex.ErrorCode;
if (errorCode == 0x80210003)
{
    MessageBox.Show("Load the scaner device!");
}
else
{
    MessageBox.Show(ex.Message);
}

for (int i = 1; i <= deviceManager.DeviceInfos.Count; i++)
{
  if (deviceManager.DeviceInfos[i].Type != WiaDeviceType.ScannerDeviceType) // Skip device If it is not a scanner
  {
    continue;
  }
  AvailableScanner = deviceManager.DeviceInfos[i];
  break;
}
if (AvailableScanner == null)
{
  return;
}
var device = AvailableScanner.Connect();
while (continueRunning2)
{
  // Are you absolutely certain you want array index 1 here?
  // Remember that arrays start at 0, so this might be a cause of
  // issues
  var ScanerItem = device.Items[1];
  ...
}

Thanks but it didn't work. now the problem is with if statement which you added.
according to your suggetion, i changed it like below:
could you please say where is the problem?

int n = 1;
bool continueRunning2 = true;
try
    {
        await Task.Run(() =>
        {
            var deviceManager = new DeviceManager();

            DeviceInfo AvailableScanner = null;

                for (int i = 1; i <= deviceManager.DeviceInfos.Count; i++)
                {
                    if (deviceManager.DeviceInfos[i].Type != WiaDeviceType.ScannerDeviceType) // Skip device If it is not a scanner
                    {
                        continue;
                    }

                    AvailableScanner = deviceManager.DeviceInfos[i];
                    break;
                }

                if (AvailableScanner != null)
                {
                    return;
                }

            var device = AvailableScanner.Connect();
            while (continueRunning2)
            {
                var ScanerItem = device.Items[1];
                var imgFile = (ImageFile)ScanerItem.Transfer();

                var data = (byte[])imgFile.FileData.get_BinaryData();
                var bitmap = GetBitmapFromRawData(imgFile.Width, imgFile.Height, data);

                var Path = @"C:\Users\...\Desktop\test\" + n + ".jpg"; // save the image in some path with filename.
                n++;
                bitmap.Save(Path, System.Drawing.Imaging.ImageFormat.Jpeg);

            }
        });

    }
    catch (COMException ex)
    {
    MessageBox.Show(ex.Message);
    }

if (AvailableScanner == null)