VB.NET Requires Chilkat v11.7.0+

Generate a QR Code PNG in Memory

See more QR Code Examples

Demonstrates getting a QR code image without writing a file. With no output options the result is a PNG returned as base64 in outputs[0].base64 of the response. The example decodes it into a BinData, which holds the bytes of the PNG to send in an HTTP response, store in a database, attach to an email, or save. VB.NET

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim json As New Chilkat.JsonObject
json.UpdateString("payload.text","https://www.chilkatsoft.com/")
json.UpdateInt("render.moduleSize",6)

Dim fmt As New Chilkat.Formats
Dim jsonOut As New Chilkat.JsonObject
success = fmt.QrCode("generate",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(fmt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("format: " & jsonOut.StringOf("outputs[0].format"))
Debug.WriteLine("MIME type: " & jsonOut.StringOf("outputs[0].mimeType"))
Debug.WriteLine("image: " & jsonOut.IntOf("outputs[0].width") & " x " & jsonOut.IntOf("outputs[0].height") & " pixels")

'  outputs[0].base64 is the PNG file, base64 encoded.
Dim bdPng As New Chilkat.BinData
success = bdPng.AppendEncoded(jsonOut.StringOf("outputs[0].base64"),"base64")
If (success = False) Then
    Debug.WriteLine(bdPng.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("PNG bytes: " & bdPng.NumBytes)

'  The BinData holds the image.  Here it is simply saved.
success = bdPng.WriteFile("qa_output/qr_in_memory.png")
If (success = False) Then
    Debug.WriteLine(bdPng.LastErrorText)
    Exit Sub
End If


'  The PNG held in bdPng:

'  

'  Sample output:

'  format: png
'  MIME type: image/png
'  image: 222 x 222 pixels
'  PNG bytes: 877