String As Byte?

[michael2]

Hi,
I need to link vb code to a C dll, but I have a problem to convert one of the argument of a function.

The function is declare like this in .pas:

test(Filename as Byte)

and like this in .h:

test(char *Filename);

Now I want to pass something like c:\test.txt in parameter, but I always get a run-time error '13' Type Mismatch.

How can I convert a string in byte to pass ByRef to the dll?

Thanks,
Michael

[berta]

U must declare arguments as string but use the option BYVAL.


public declare Test lib "mylib.dll" (byval string filename)

private sub command1_click
dim Filename as string
Filename="myfile.txt"
test(Filename)
end sub

private sub command2_click
test("myfile.txt")
end sub






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<img src='http://web.tiscali.it/bertaplanet/im...ertaplanet.gif'>
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[michael2]

I can't change the declaration in .bas

I found how to pass the string in bytes, but I got a new problem... Here is what I do:


public declare Test lib "mylib.dll" (filename as Byte
private sub command1_click
dim Filename() as Byte
Filename="myfile.txt"
test(Filename(0))
end sub




My problem is that Filename does not contain myfile.txt, but contains m0y0f0i0l0e0.0t0x0t0. I have a string terminator after each byte, so the Test function only receive m, because the string is null terminated after it.

How can I have myfile.txt in Filename?

Thanks,
Michael

[berta]

but why not so?


public declare Test lib "mylib.dll" (byval filename as string)

private sub command1_click
dim Filename() as string
Filename="myfile.txt"
test(Filename)
end sub






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<HR width=80%>
<img src='http://web.tiscali.it/bertaplanet/im...ertaplanet.gif'>
</center>

[berta]

using option byval...

dim filename as string* 255
filname="myfile.txt"
test(filename)

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<img src='http://web.tiscali.it/bertaplanet/im...ertaplanet.gif'>
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[DSJ]

Give this a shot....


public declare Test lib "mylib.dll" (filename as Byte)
private Sub command1_click()
Dim Filename() as Byte


Filename = StrConv("myfile.txt", vbFromUnicode)
Test (Filename(0))
End Sub

[michael2]

That's what I did and it works.

Thanks.