Question

I am trying to use MessagingToolkit to decode an image in C#/ASP.NET. I have managed to encode a qr using this package, but when i try to decode, using the code below it comes up with 2 errors (at the bottom of the page)

I believe this is because I am not getting the image correctly after uploading, but can someone point out exactly where I have gone wrong. Thanks.

    protected void CreateCode_OnClick(object sender, EventArgs e)
    {
        string path = "C:\\Users\\Wayneio\\Documents\\Visual Studio 2012\\Projects\\BAMSystem\\BAMSystem\\";
        if (QRUpload.HasFiles == true)
        {
            FileInfo fi = new FileInfo(QRUpload.FileName);
            string extA = fi.Extension;
            if (extA == ".jpg" || extA == ".png")
            {
               QRCodeDecoder decoder = new QRCodeDecoder();
               QRUpload.SaveAs(path + QRUpload.FileName);

               System.Drawing.Image myImg = System.Drawing.Image.FromFile(path + QRUpload.FileName);
               decoder.Decode(myImg);

            }
            else
            {
                error.Text = "You have uploaded a " + extA + " file. Please upload either a PNG or a JPG";
            }
        }
        else
        {
            error.Text = "You have not uploaded an image.";
        }
    }

Error1:

Error   2   Argument 1: cannot convert from 'System.Drawing.Image' to 'MessagingToolkit.QRCode.Codec.Data.QRCodeImage'  c:\users\wayneio\documents\visual studio 2012\Projects\BAMSystem\BAMSystem\default.aspx.cs  38  35  BAMSystem

Error2:

Error   1   The best overloaded method match for 'MessagingToolkit.QRCode.Codec.QRCodeDecoder.Decode(MessagingToolkit.QRCode.Codec.Data.QRCodeImage)' has some invalid arguments    c:\users\wayneio\documents\visual studio 2012\Projects\BAMSystem\BAMSystem\default.aspx.cs  38  20  BAMSystem

P.S if anyone has documentation on this MessagingToolkit QR package, it would be useful

Answer 1

Decode accepts ‘Bitmap’ type image.

System.Drawing.Bitmap myImg = new System.Drawing.Bitmap(FileName);
Dictionary<DecodeOptions, object> decodingOptions = new Dictionary<DecodeOptions, object>();
List<BarcodeFormat> possibleFormats = new List<BarcodeFormat>(10);

                        possibleFormats.Add(BarcodeFormat.DataMatrix);
                        possibleFormats.Add(BarcodeFormat.QRCode);
                        possibleFormats.Add(BarcodeFormat.PDF417);
                        possibleFormats.Add(BarcodeFormat.Aztec);
                        possibleFormats.Add(BarcodeFormat.UPCE);
                        possibleFormats.Add(BarcodeFormat.UPCA);
                        possibleFormats.Add(BarcodeFormat.Code128);
                        possibleFormats.Add(BarcodeFormat.Code39);
                        possibleFormats.Add(BarcodeFormat.ITF14);
                        possibleFormats.Add(BarcodeFormat.EAN8);
                        possibleFormats.Add(BarcodeFormat.EAN13);
                        possibleFormats.Add(BarcodeFormat.RSS14);
                        possibleFormats.Add(BarcodeFormat.RSSExpanded);
                        possibleFormats.Add(BarcodeFormat.Codabar);
                        possibleFormats.Add(BarcodeFormat.MaxiCode);

 decodingOptions.Add(DecodeOptions.TryHarder, true);
 decodingOptions.Add(DecodeOptions.PossibleFormats, possibleFormats);
Result decodedResult = decoder.Decode(myImg, decodingOptions);

          if (decodedResult != null)
                        {
                          //.. success
                        }

Also you can also omit the “decodingOptions” options parameter as decoder also has an overload Decode(Bitmap image).

System.Drawing.Bitmap myImg = new System.Drawing.Bitmap(FileName);
Result decodedResult = decoder.Decode(myImg);

          if (decodedResult != null)
                        {
                          //.. success
                        }

If you want only QRCode decoding,

    System.Drawing.Bitmap myImg = new System.Drawing.Bitmap(FileName);
    Dictionary<DecodeOptions, object> decodingOptions = new Dictionary<DecodeOptions, object>();
    List<BarcodeFormat> possibleFormats = new List<BarcodeFormat>();
    possibleFormats.Add(BarcodeFormat.QRCode);                              
    decodingOptions.Add(DecodeOptions.TryHarder, true);
    decodingOptions.Add(DecodeOptions.PossibleFormats, possibleFormats);
    Result decodedResult = decoder.Decode(myImg, decodingOptions);
     if (decodedResult != null)
       {
          //.. success
       }

You can find documentation and code here
http://platform.twit88.com/projects/show/mt-barcode

Sample code ..download here ..has demo code also
http://platform.twit88.com/projects/mt-barcode/files

Code project here
http://www.codeproject.com/Articles/20574/Open-Source-QRCode-Library