Windows图像获取-在C#中设置设备属性

Question

我有一个 C# (WinForm) 程序，支持使用 WIA 进行扫描。 我试图在扫描一份或多份文档之前设置设备属性。 我主要想设置扫描仪的纸张尺寸。 以下是代码片段：

foreach (Property property in selectedDevice.Properties)
{
   //WiaProperties.WiaDpsHorizontalBedSize is my constant
   if (property.PropertyID == WiaProperties.WiaDpsHorizontalBedSize)
   {
       //Set property value here...             
   }
}

我正在查找“水平床尺寸”属性，但问题是如何将其设置为一个值？ 属性中有一个 set_Value 属性，但它似乎引用了结果对象。 所以我不知道如何在设备上设置属性？

Answer 1

我也在做一个扫描项目，WIA 的例子很少。 您需要这段代码来设置床尺寸、DPI 等。查看 SetProperty 方法，其中包含有关如何处理 set_Value 的示例。

class Scan
{
    // Scanner only device properties (DPS)
    public const int WIA_RESERVED_FOR_NEW_PROPS = 1024;
    public const int WIA_DIP_FIRST = 2;
    public const int WIA_DPA_FIRST = WIA_DIP_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
    public const int WIA_DPC_FIRST = WIA_DPA_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
    public const int WIA_DPS_FIRST = WIA_DPC_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
    public const int WIA_DPS_DOCUMENT_HANDLING_STATUS = WIA_DPS_FIRST + 13;
    public const int WIA_DPS_DOCUMENT_HANDLING_SELECT = WIA_DPS_FIRST + 14;
    public const int FEEDER = 1;
    public const int FLATBED = 2;
    public const int DUPLEX = 4;
    public const int FEED_READY = 1;

    WIA.CommonDialog _dialog = new WIA.CommonDialog();
    WIA.Device _scanner;

    public void ADFScan()
    {

        _dialog = new CommonDialogClass();
        _scanner = _dialog.ShowSelectDevice(WIA.WiaDeviceType.ScannerDeviceType, false, false);


        foreach (Property item in _scanner.Items[1].Properties)
        {
            switch (item.PropertyID)
            {
                case 6146: //4 is Black-white,gray is 2, color 1
                    SetProperty(item, 2);
                    break;
                case 6147: //dots per inch/horizontal 
                    SetProperty(item, 100);
                    break;
                case 6148: //dots per inch/vertical 
                    SetProperty(item, 100);
                    break;
                case 6149: //x point where to start scan 
                    SetProperty(item, 0);
                    break;
                case 6150: //y-point where to start scan 
                    SetProperty(item, 0);
                    break;
                case 6151: //horizontal exent 
                    SetProperty(item, (int)(8.5 * 100));
                    break;
                case 6152: //vertical extent 
                    SetProperty(item, 11 * 100);
                    break;
            }
        }
        ImageFile image = (ImageFile)_scanner.Items[1].Transfer(FormatID.wiaFormatPNG);
        System.IO.File.Delete("tmp.png");
        image.SaveFile("tmp.png");
    }

    private void SetProperty(Property property, int value)
    {
        IProperty x = (IProperty)property;
        Object val = value;
        x.set_Value(ref val);
    }


    public void test()
    {
        bool WantsToScan = true;
        while (WantsToScan) ScanAndSaveOnePage();

    }


    static void Main(string[] args)
    {
        new Scan().test();
    }
}