I thought I had it under control but no…
Here’s another translation from VB that I can not get to work, using declares… in this case the problem is the usage of BYTE as a datatype.
VB6 code
Example1
[code]
Private Declare Function GetVersionInfo Lib “IDCard.dll” (ByRef lpBuffer As Byte, ByVal nBufferLenth As Long) As Long
Dim MAX_CH_NUM As Long
MAX_CH_NUM = 50
Dim strTmp(50) As Byte
[code]
Private Declare Function GetRecogResult Lib “IDCard.dll” (ByVal nIndex As Long, ByRef lpBuffer As Byte, ByRef nBufferLen As Long) As Long
Private Declare Function GetFieldName Lib "IDCard.dll" (ByVal nIndex As Long, ByRef llpBuffe As Byte, ByRef nBufferLen As Long) As Long
Dim MAX_CH_NUM As Long
MAX_CH_NUM = 128
Dim szFieldValue(255) As Byte
Dim szFieldName(255) As Byte
Dim nIndex As Long
nIndex = 1
ResultTextBox.Text = "recognition successful" & vbCrLf
Dim output As Long
output = 1
Do While (output)
If nRet <> 3 Then
Dim strTmp(255) As Byte
Dim strTmp1(255) As Byte
nRet = GetRecogResult(nIndex, szFieldValue(0), MAX_CH_NUM)
Dim nnRet As Long
nnRet = GetFieldName(nIndex, szFieldName(0), MAX_CH_NUM)
Dim strFieldName As String
If nnRet = 0 Then
strFieldName = szFieldName
ResultTextBox.Text = ResultTextBox.Text + strFieldName
ResultTextBox.Text = ResultTextBox.Text + ": "
strFieldName = szFieldValue
ResultTextBox.Text = ResultTextBox.Text + strFieldName
ResultTextBox.Text = ResultTextBox.Text + vbCrLf
End If
nIndex = nIndex + 1
Else
output = 0
End If
Loop[/code]
I am not sure where to start… first… what si the analogous to BYTE in xojo ? and also why szFieldValue and szFieldName have a value between parenthesis… is this an offset ? o r some kind of array ?
I imagine I have to use memblocks ?
Can anyone help ?
I need to get this dll working…
BYTE is usually a UINT8
But szFieldValue(255) becomes a new memoryblock(255)… the 255 tells vb to make the string exactly 255 bytes long
And a memoryblock can be addressed like an array of bytes mb.byte(6) for example
In this case you expect a string, so just take the stringvalue of the memoryblock
[quote=367306:@Jeff Tullin]BYTE is usually a UINT8
But szFieldValue(255) becomes a new memoryblock(255)… the 255 tells vb to make the string exactly 255 bytes long
And a memoryblock can be addressed like an array of bytes mb.byte(6) for example
In this case you expect a string, so just take the stringvalue of the memoryblock[/quote]
and use
Soft Declare Function GetVersionInfo Lib "IDCard.dll" (lpBuffer As ptr, nBufferLenth As Integer) As Integer
Soft Declare Function GetRecogResult Lib "IDCard.dll" (nIndex As Integer, lpBuffer As ptr, ByRef nBufferLen As Integer) As Integer
Soft Declare Function GetFieldName Lib "IDCard.dll" (nIndex As Integer, llpBuffe As ptr, ByRef nBufferLen As Integer) As Integer
Function Get the SDK Version
lpBuffer Save the version information , the memory size should not be less than 100 bytes
nBufferLen the memory size of the lpBuffer Return value TURE for success FALSE for failure
I tried this code in Xojo… but did not work…
[code] Dim lpBuffer as WString
Declare Function GetVersionInfo Lib “IDCard.dll” (ByRef lpBuffer as wstring, nBufferLenth As integer) As integer
nRet = GetVersionInfo(lpBuffer, 128)
ResultTextBox.Text = lpBuffer[/code]
I also tried passing a memory block… but objects can’t used within declares…
Declare Function GetVersionInfo Lib "IDCard.dll" (lpBuffer as ptr, nBufferLenth As integer) As integer
Dim lpBuffer as new MemoryBlock(128)
nRet = GetVersionInfo(lpBuffer, lpBuffer.size)
ResultTextBox.Text = lpBuffer.WString(0)
I can help you if you would like. I will be near my development computer in a couple of hours. Do you happen to have a download link for the idcard.dll file?
I got it working now, thanks to the help from the folks in this forum… I will begin reading the book later tonight for a deeper understanding of the concept.
Is it ok to create a method for each declare… and the call this method every time I need to interact with the API (and then when the method ends the declare goes out of scope) ?
Or this there something like VB’s general (Global) declarations where all declares go together once ?
I like how they say 100 bytes in the doc then give an example with 50… facepalm
Just make sure you’re setting aside enough space for the returned data.
If they are sending back up to 100 “characters” and you’re receiving them in wide format (UTF-16) then I’d suggest doubling their 100 byte request to at least 200 bytes in your receive buffer length.
It’s interesting that they spec byte then Asis’ example works with WString (which is 2 bytes per character), its almost like they have updated the dll to Unicode and not updated the docs.
Fun fun
PS. See https://blog./2017/01/22/windows-to-xojo-data-type-conversion/ if you want a searchable list for future declares. I’m glad you picked up Eugene’s book, its very handy
PPS. https://forum.xojo.com/conversation/post/367317 would have worked if you had pre-filled lpBuffer with 128 spaces before the call, but memoryblocks are neater and more versatile solution
