midi API MIDIHDR String MarshalAs...

[Tim]

I am having problems using interop to call midiOutLongMsg.

in my MIDIHDR struct, i allocate MsgData as a string

I have been using a StringBuilder object to build MsgData
per byte. I am not getting the proper results, although
sometimes I do hear some notes being played, just not the
right ones...

What I think is happening is that when I do something like:

byte b=153;
Stringbuilder sb = new StringBuilder();
sb.Append(b);

i am appending the "string representation" of the byte.
ie "153" instead of just the one byte with a value of 153.
I am going to dive into the System.Text namespace, but
wanted to see if I could learn something here.

Really I have 2 questions:
1) How to append the actual byte to a stringbuilder
(byte2string function of somesort?)

2) How to properly determine the byte length of the
string. (sb.Length, sb.Capacity, sb.ToString
().SizeOf...???)

Thanks,
Tim.

[Tim]

I am close to a solution, maybe:

using:
ASCIIEncoding.GetString Method (Byte[])

will give me a string that represents an array of bytes.
However, there is a restriction:

"Any element of the bytes array that is greater than
hexadecimal 0x7F is translated to a Unicode question mark
('?')."

I need to use that extra bit. Also, assuming that I get
the proper string of bytes, what must I do to insure that
it doesn't get hacked up by the marshal?

Tim.

-----Original Message-----
I am having problems using interop to call midiOutLongMsg.

in my MIDIHDR struct, i allocate MsgData as a string

I have been using a StringBuilder object to build MsgData
per byte. I am not getting the proper results, although
sometimes I do hear some notes being played, just not the
right ones...

What I think is happening is that when I do something like:
byte b=153;
Stringbuilder sb = new StringBuilder();
sb.Append(b);

i am appending the "string representation" of the byte.
ie "153" instead of just the one byte with a value of 153.
I am going to dive into the System.Text namespace, but
wanted to see if I could learn something here.

Really I have 2 questions:
1) How to append the actual byte to a stringbuilder
(byte2string function of somesort?)

2) How to properly determine the byte length of the
string. (sb.Length, sb.Capacity, sb.ToString
().SizeOf...???)

Thanks,
Tim.

.

[Jhon]

Hi,
[inline]

"Tim" <an*******@discussions.microsoft.com> wrote in message
news:00****************************@phx.gbl...

I am close to a solution, maybe:

using:
ASCIIEncoding.GetString Method (Byte[])

will give me a string that represents an array of bytes.
However, there is a restriction:

"Any element of the bytes array that is greater than
hexadecimal 0x7F is translated to a Unicode question mark
('?')."

I need to use that extra bit. Also, assuming that I get
the proper string of bytes, what must I do to insure that
it doesn't get hacked up by the marshal?

Tim.

-----Original Message-----
I am having problems using interop to call midiOutLongMsg.

in my MIDIHDR struct, i allocate MsgData as a string

I have been using a StringBuilder object to build MsgData
per byte. I am not getting the proper results, although
sometimes I do hear some notes being played, just not the
right ones...

What I think is happening is that when I do something

like:

byte b=153;
Stringbuilder sb = new StringBuilder();
sb.Append(b);

i am appending the "string representation" of the byte.
ie "153" instead of just the one byte with a value of 153.
I am going to dive into the System.Text namespace, but
wanted to see if I could learn something here.

Really I have 2 questions:
1) How to append the actual byte to a stringbuilder
(byte2string function of somesort?)
Cast the byte to a char, like sb.Append ( (char) b), this will not change
the number.
There might be other ways though...

2) How to properly determine the byte length of the
string. (sb.Length, sb.Capacity, sb.ToString
().SizeOf...???) Length

HTH,
greetings

Thanks,
Tim.

[Mattias Sjögren]

in my MIDIHDR struct, i allocate MsgData as a string

If you're working with binary data, it's better to use a byte[] than a
string.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/
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