convert a C# string to a unmanaged C char

[Jim]

I have to access a third party api to work with their
hardware. Everything was going great UNTIL I ran into the
problem of C# char being 16 bits and the C char being 8
bits. I cannot seem to cast the string properly to use it
in the unmanaged code.

I have tried to use the MarshalAs function in my DllImport
statement but that didn't work.

What i need is to take a string of numbers and convert it
to a Zero Terminated C string or char. Can anyone please
help me.

[Michael Culley]

Re: convert a C# string to a unmanaged C char

"Jim" <jime@kc.rr.com > wrote in message news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue]
> I have to access a third party api to work with their
> hardware. Everything was going great UNTIL I ran into the
> problem of C# char being 16 bits and the C char being 8
> bits. I cannot seem to cast the string properly to use it
> in the unmanaged code.[/color]

You shouldn't have to do anything, it should just marshal accross as an 8 bit null terminated char* that will work in C. eg

[DllImport("user 32", EntryPoint= "MessageBox A")]
private static extern int MessageBox(IntP tr hwnd, String lpText, String lpCaption, int wType);

--
Michael Culley


"Jim" <jime@kc.rr.com > wrote in message news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue]
> I have to access a third party api to work with their
> hardware. Everything was going great UNTIL I ran into the
> problem of C# char being 16 bits and the C char being 8
> bits. I cannot seem to cast the string properly to use it
> in the unmanaged code.
>
> I have tried to use the MarshalAs function in my DllImport
> statement but that didn't work.
>
> What i need is to take a string of numbers and convert it
> to a Zero Terminated C string or char. Can anyone please
> help me.[/color]

[Habib Heydarian [MSFT]]

Re: convert a C# string to a unmanaged C char

What do you get if you specify CharSet=CharSet .Auto in the DllImport
declaration?

HabibH.

"Jim" <jime@kc.rr.com > wrote in message
news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue]
> I have to access a third party api to work with their
> hardware. Everything was going great UNTIL I ran into the
> problem of C# char being 16 bits and the C char being 8
> bits. I cannot seem to cast the string properly to use it
> in the unmanaged code.
>
> I have tried to use the MarshalAs function in my DllImport
> statement but that didn't work.
>
> What i need is to take a string of numbers and convert it
> to a Zero Terminated C string or char. Can anyone please
> help me.[/color]

[Guest]

Re: convert a C# string to a unmanaged C char

[color=blue]
>-----Original Message-----
>"Jim" <jime@kc.rr.com > wrote in message[/color]
news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue][color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.[/color]
>
>You shouldn't have to do anything, it should just marshal[/color]
accross as an 8 bit null terminated char* that will work
in C. eg[color=blue]
>
>[DllImport("user 32", EntryPoint= "MessageBox A")]
>private static extern int MessageBox(IntP tr hwnd, String[/color]
lpText, String lpCaption, int wType);[color=blue]
>
>--
>Michael Culley
>
>
>"Jim" <jime@kc.rr.com > wrote in message[/color]
news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue][color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.
>>
>> I have tried to use the MarshalAs function in my[/color][/color]
DllImport[color=blue][color=green]
>> statement but that didn't work.
>>
>> What i need is to take a string of numbers and convert[/color][/color]
it[color=blue][color=green]
>> to a Zero Terminated C string or char. Can anyone[/color][/color]
please[color=blue][color=green]
>> help me.[/color]
>
>
>.[/color]


I have read that a string should marshal as a char* but
for some reason mine is not doing it.
this is my dll declaration
[DllImport("Pika Api.dll")]
public static extern int PK_VP_PlayDMTFS tring(uint hPort,
string PK_PCHAR);

then I call it from my code
string x = textBox1.text;
if(PK_VP_PlayDM TFString(hBoard Port, x) == PK_SUCCESS)

but it doesn't work.

any ideas?[color=blue]
>[/color]

[Guest]

Re: convert a C# string to a unmanaged C char

[color=blue]
>-----Original Message-----
>What do you get if you specify CharSet=CharSet .Auto in[/color]
the DllImport[color=blue]
>declaration?
>
>HabibH.
>
>"Jim" <jime@kc.rr.com > wrote in message
>news:07aa01c3a 98e$6b16c390$a3 01280a@phx.gbl. ..[color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.
>>
>> I have tried to use the MarshalAs function in my[/color][/color]
DllImport[color=blue][color=green]
>> statement but that didn't work.
>>
>> What i need is to take a string of numbers and convert[/color][/color]
it[color=blue][color=green]
>> to a Zero Terminated C string or char. Can anyone[/color][/color]
please[color=blue][color=green]
>> help me.[/color]
>
>
>.[/color]

I have not tried that.....[color=blue]
>[/color]

[jim]

Re: convert a C# string to a unmanaged C char

I have read that the string will marshal over to a char*
but for some reason it didn't owrk for me.

here is my DllImport code

[DllImport("Pika API.dll")]
public static extern uint PK_VP_PlayDTMFS tring(uint
BoardPort, string PK_PCHAR);

then I call it using

string x = textBox1.text;
PK_VP_PlayDTMFS tring(hPort, x);

but not luck. any ideas?


[color=blue]
>-----Original Message-----
>"Jim" <jime@kc.rr.com > wrote in message[/color]
news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue][color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.[/color]
>
>You shouldn't have to do anything, it should just marshal[/color]
accross as an 8 bit null terminated char* that will work
in C. eg[color=blue]
>
>[DllImport("user 32", EntryPoint= "MessageBox A")]
>private static extern int MessageBox(IntP tr hwnd, String[/color]
lpText, String lpCaption, int wType);[color=blue]
>
>--
>Michael Culley
>
>
>"Jim" <jime@kc.rr.com > wrote in message[/color]
news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=blue][color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.
>>
>> I have tried to use the MarshalAs function in my[/color][/color]
DllImport[color=blue][color=green]
>> statement but that didn't work.
>>
>> What i need is to take a string of numbers and convert[/color][/color]
it[color=blue][color=green]
>> to a Zero Terminated C string or char. Can anyone[/color][/color]
please[color=blue][color=green]
>> help me.[/color]
>
>
>.
>[/color]

[jim]

Re: convert a C# string to a unmanaged C char

I have not tried that, I will try it first thing tomorrow.

[color=blue]
>-----Original Message-----
>What do you get if you specify CharSet=CharSet .Auto in[/color]
the DllImport[color=blue]
>declaration?
>
>HabibH.
>
>"Jim" <jime@kc.rr.com > wrote in message
>news:07aa01c3a 98e$6b16c390$a3 01280a@phx.gbl. ..[color=green]
>> I have to access a third party api to work with their
>> hardware. Everything was going great UNTIL I ran into[/color][/color]
the[color=blue][color=green]
>> problem of C# char being 16 bits and the C char being 8
>> bits. I cannot seem to cast the string properly to use[/color][/color]
it[color=blue][color=green]
>> in the unmanaged code.
>>
>> I have tried to use the MarshalAs function in my[/color][/color]
DllImport[color=blue][color=green]
>> statement but that didn't work.
>>
>> What i need is to take a string of numbers and convert[/color][/color]
it[color=blue][color=green]
>> to a Zero Terminated C string or char. Can anyone[/color][/color]
please[color=blue][color=green]
>> help me.[/color]
>
>
>.
>[/color]

[Michael Culley]

Re: convert a C# string to a unmanaged C char

I just tried this code and it worked ok. Try this on your system and see what you get. Maybe there is a global option that causes it
to marshal as unicode or maybe it thinks your function is unicode because it doesn't end in a capital A. Try using
CharSet=CharSet .Ansi

[DllImport("user 32", EntryPoint= "MessageBox A")]
private static extern int MessageBoxAPI(I ntPtr hwnd, string lpText, string lpCaption, int wType);

string x = "This is a test!";
string y = "Test caption!";
MessageBoxAPI(t his.Handle, x, y, 0);

--
Michael Culley


"jim" <jime@kc.rr.com > wrote in message news:0f1601c3a9 92$34e2e430$a00 1280a@phx.gbl.. .[color=blue]
> I have read that the string will marshal over to a char*
> but for some reason it didn't owrk for me.
>
> here is my DllImport code
>
> [DllImport("Pika API.dll")]
> public static extern uint PK_VP_PlayDTMFS tring(uint
> BoardPort, string PK_PCHAR);
>
> then I call it using
>
> string x = textBox1.text;
> PK_VP_PlayDTMFS tring(hPort, x);
>
> but not luck. any ideas?
>
>
>[color=green]
> >-----Original Message-----
> >"Jim" <jime@kc.rr.com > wrote in message[/color]
> news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=green][color=darkred]
> >> I have to access a third party api to work with their
> >> hardware. Everything was going great UNTIL I ran into[/color][/color]
> the[color=green][color=darkred]
> >> problem of C# char being 16 bits and the C char being 8
> >> bits. I cannot seem to cast the string properly to use[/color][/color]
> it[color=green][color=darkred]
> >> in the unmanaged code.[/color]
> >
> >You shouldn't have to do anything, it should just marshal[/color]
> accross as an 8 bit null terminated char* that will work
> in C. eg[color=green]
> >
> >[DllImport("user 32", EntryPoint= "MessageBox A")]
> >private static extern int MessageBox(IntP tr hwnd, String[/color]
> lpText, String lpCaption, int wType);[color=green]
> >
> >--
> >Michael Culley
> >
> >
> >"Jim" <jime@kc.rr.com > wrote in message[/color]
> news:07aa01c3a9 8e$6b16c390$a30 1280a@phx.gbl.. .[color=green][color=darkred]
> >> I have to access a third party api to work with their
> >> hardware. Everything was going great UNTIL I ran into[/color][/color]
> the[color=green][color=darkred]
> >> problem of C# char being 16 bits and the C char being 8
> >> bits. I cannot seem to cast the string properly to use[/color][/color]
> it[color=green][color=darkred]
> >> in the unmanaged code.
> >>
> >> I have tried to use the MarshalAs function in my[/color][/color]
> DllImport[color=green][color=darkred]
> >> statement but that didn't work.
> >>
> >> What i need is to take a string of numbers and convert[/color][/color]
> it[color=green][color=darkred]
> >> to a Zero Terminated C string or char. Can anyone[/color][/color]
> please[color=green][color=darkred]
> >> help me.[/color]
> >
> >
> >.
> >[/color][/color]