Get WIA scanner features

Question

How do you get a scanner's available resolutions and/or dpi. Also, how to get the information that it has an automatic document feeder, etc?

Answer 1

You can retrieve the features available for your scanner by navigating through the Properties object like Matthias suggested to you. Here is an enum I use with all the properties and their IDs:

public enum WiaProperty
{
    DeviceId = 2,
    Manufacturer = 3,
    Description = 4,
    Type = 5,
    Port = 6,
    Name = 7,
    Server = 8,
    RemoteDevId = 9,
    UIClassId = 10,
    FirmwareVersion = 1026,
    ConnectStatus = 1027,
    DeviceTime = 1028,
    PicturesTaken = 2050,
    PicturesRemaining = 2051,
    ExposureMode = 2052,
    ExposureCompensation = 2053,
    ExposureTime = 2054,
    FNumber = 2055,
    FlashMode = 2056,
    FocusMode = 2057,
    FocusManualDist = 2058,
    ZoomPosition = 2059,
    PanPosition = 2060,
    TiltPostion = 2061,
    TimerMode = 2062,
    TimerValue = 2063,
    PowerMode = 2064,
    BatteryStatus = 2065,
    Dimension = 2070,
    HorizontalBedSize = 3074,
    VerticalBedSize = 3075,
    HorizontalSheetFeedSize = 3076,
    VerticalSheetFeedSize = 3077,
    SheetFeederRegistration = 3078,         // 0 = LEFT_JUSTIFIED, 1 = CENTERED, 2 = RIGHT_JUSTIFIED
    HorizontalBedRegistration = 3079,       // 0 = LEFT_JUSTIFIED, 1 = CENTERED, 2 = RIGHT_JUSTIFIED
    VerticalBedRegistraion = 3080,          // 0 = TOP_JUSTIFIED, 1 = CENTERED, 2 = BOTTOM_JUSTIFIED
    PlatenColor = 3081,
    PadColor = 3082,
    FilterSelect = 3083,
    DitherSelect = 3084,
    DitherPatternData = 3085,

    DocumentHandlingCapabilities = 3086,    // FEED = 0x01, FLAT = 0x02, DUP = 0x04, DETECT_FLAT = 0x08, 
                                            // DETECT_SCAN = 0x10, DETECT_FEED = 0x20, DETECT_DUP = 0x40, 
                                            // DETECT_FEED_AVAIL = 0x80, DETECT_DUP_AVAIL = 0x100
    DocumentHandlingStatus = 3087,          // FEED_READY = 0x01, FLAT_READY = 0x02, DUP_READY = 0x04, 
                                            // FLAT_COVER_UP = 0x08, PATH_COVER_UP = 0x10, PAPER_JAM = 0x20
    DocumentHandlingSelect = 3088,          // FEEDER = 0x001, FLATBED = 0x002, DUPLEX = 0x004, FRONT_FIRST = 0x008
                                            // BACK_FIRST = 0x010, FRONT_ONLY = 0x020, BACK_ONLY = 0x040
                                            // NEXT_PAGE = 0x080, PREFEED = 0x100, AUTO_ADVANCE = 0x200
    DocumentHandlingCapacity = 3089, 
    HorizontalOpticalResolution = 3090,
    VerticalOpticalResolution = 3091,
    EndorserCharacters = 3092,
    EndorserString = 3093,
    ScanAheadPages = 3094,                  // ALL_PAGES = 0
    MaxScanTime = 3095,
    Pages = 3096,                           // ALL_PAGES = 0
    PageSize = 3097,                        // A4 = 0, LETTER = 1, CUSTOM = 2
    PageWidth = 3098,
    PageHeight = 3099,
    Preview = 3100,                         // FINAL_SCAN = 0, PREVIEW = 1
    TransparencyAdapter = 3101,
    TransparecnyAdapterSelect = 3102,
    ItemName = 4098,
    FullItemName = 4099,
    ItemTimeStamp = 4100,
    ItemFlags = 4101,
    AccessRights = 4102,
    DataType = 4103,
    BitsPerPixel = 4104,
    PreferredFormat = 4105,
    Format = 4106,
    Compression = 4107,                     // 0 = NONE, JPG = 5, PNG = 8
    MediaType = 4108,
    ChannelsPerPixel = 4109,
    BitsPerChannel = 4110,
    Planar = 4111,
    PixelsPerLine = 4112,
    BytesPerLine = 4113,
    NumberOfLines = 4114,
    GammaCurves = 4115,
    ItemSize = 4116,
    ColorProfiles = 4117,
    BufferSize = 4118,
    RegionType = 4119,
    ColorProfileName = 4120,
    ApplicationAppliesColorMapping = 4121,
    StreamCompatibilityId = 4122,
    ThumbData = 5122,
    ThumbWidth = 5123,
    ThumbHeight = 5124,
    AudioAvailable = 5125,
    AudioFormat = 5126,
    AudioData = 5127,
    PicturesPerRow = 5128,
    SequenceNumber = 5129,
    TimeDelay = 5130,
    CurrentIntent = 6146,
    HorizontalResolution = 6147,
    VerticalResolution = 6148,
    HorizontalStartPosition = 6149,
    VerticalStartPosition = 6150,
    HorizontalExtent = 6151,
    VerticalExtent = 6152,
    PhotometricInterpretation = 6153,
    Brightness = 6154,
    Contrast = 6155,
    Orientation = 6156, // 0 = PORTRAIT, 1 = LANDSCAPE, 2 = 180°, 3 = 270°
    Rotation = 6157, // 0 = PORTRAIT, 1 = LANDSCAPE, 2 = 180°, 3 = 270°
    Mirror = 6158,
    Threshold = 6159,
    Invert = 6160,
    LampWarmUpTime = 6161,
}

For the possible values of every single property you can read the MSDN documentation:

MSDN WIA Documentation

or if you want to get deeper, you can analyze the header files of the original SDK.