Unicode in a native DLL?

[ORC]

Hi,

How to transfer strings between a C# .NET application and a native DLL that
uses Unicode like:
#ifndef UNICODE
#define UNICODE
#endif

The function header in the DLL:
BOOL NewDataBase(LPCTSTR strDbFileName)

The definition in C#:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true)]
public static extern bool NewDataBase(string FileName);

Thanks,
Ole

[ORC]

HI,
saw the moment I pressed the send button: I forgot the charset option:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true, CharSet = CharSet.Unicode)]

Now it works!

Thanks anyway,
Ole

"ORC" <or*@sol.dk> wrote in message
news:%2*****************@TK2MSFTNGP12.phx.gbl...

Hi,

How to transfer strings between a C# .NET application and a native DLL that uses Unicode like:
#ifndef UNICODE
#define UNICODE
#endif

The function header in the DLL:
BOOL NewDataBase(LPCTSTR strDbFileName)

The definition in C#:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true)]
public static extern bool NewDataBase(string FileName);

Thanks,
Ole

[GingerDeafMan]

Hi Ole and the rest,

Have just subscribed to this NG and found this. I have a similar
problem.

I am trying to get a function in C++ DLL to return a string.

Code in DLL is (a portion)

#define WINDLL __declspec(dllexport) CALLBACK
void WINDLL GetName(LPCTSTR szMfr)
{
sprintf((char *)szMfr,"%s",A.Name);
}

"Name" is char array.

Code in C# is

[DllImport("C:\\MyDLL.DLL",
EntryPoint="GetName",CharSet=CharSet.Auto)]
private static extern void GetName(string strName);

This throws an exception

string strName;
GetName(strName);

I am stuck here, obviously. Any ideas as what I am doing wrong, or
alternative methods for passing char arrays back from the DLL to C# as a
string would be welcome.

TIA,

Cheers,

Paul.
In article <u6**************@TK2MSFTNGP12.phx.gbl>, or*@sol.dk says...

HI,
saw the moment I pressed the send button: I forgot the charset option:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true, CharSet = CharSet.Unicode)]

Now it works!

Thanks anyway,
Ole

"ORC" <or*@sol.dk> wrote in message
news:%2*****************@TK2MSFTNGP12.phx.gbl...

Hi,

How to transfer strings between a C# .NET application and a native DLL

that

uses Unicode like:
#ifndef UNICODE
#define UNICODE
#endif

The function header in the DLL:
BOOL NewDataBase(LPCTSTR strDbFileName)

The definition in C#:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true)]
public static extern bool NewDataBase(string FileName);

Thanks,
Ole

[Willy Denoyette [MVP]]

What exception?
Your function is expecting an ANSI string, so you should use CharSet.Ansi
And you don't return anything.

Willy.

"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

Hi Ole and the rest,

Have just subscribed to this NG and found this. I have a similar
problem.

I am trying to get a function in C++ DLL to return a string.

Code in DLL is (a portion)

#define WINDLL __declspec(dllexport) CALLBACK
void WINDLL GetName(LPCTSTR szMfr)
{
sprintf((char *)szMfr,"%s",A.Name);
}

"Name" is char array.

Code in C# is

[DllImport("C:\\MyDLL.DLL",
EntryPoint="GetName",CharSet=CharSet.Auto)]
private static extern void GetName(string strName);

This throws an exception

string strName;
GetName(strName);

I am stuck here, obviously. Any ideas as what I am doing wrong, or
alternative methods for passing char arrays back from the DLL to C# as a
string would be welcome.

TIA,

Cheers,

Paul.
In article <u6**************@TK2MSFTNGP12.phx.gbl>, or*@sol.dk says...

HI,
saw the moment I pressed the send button: I forgot the charset option:
[DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
SetLastError=true, CharSet = CharSet.Unicode)]

Now it works!

Thanks anyway,
Ole

"ORC" <or*@sol.dk> wrote in message
news:%2*****************@TK2MSFTNGP12.phx.gbl...

> Hi,
>
> How to transfer strings between a C# .NET application and a native DLL

that

> uses Unicode like:
> #ifndef UNICODE
> #define UNICODE
> #endif
>
> The function header in the DLL:
> BOOL NewDataBase(LPCTSTR strDbFileName)
>
> The definition in C#:
> [DllImport("miniDataservice.dll", EntryPoint="NewDataBase",
> SetLastError=true)]
> public static extern bool NewDataBase(string FileName);
>
> Thanks,
> Ole
>
>

[GingerDeafMan]

Hi Willy,

Thanks for this.

Have already tried CharSet.Ansi. Makes no difference.

The exception is

An unhandled exception of type 'System.NullReferenceException' occurred
in nch.dll

Additional information: Object reference not set to an instance of an
object

Paul.

In article <Oh**************@TK2MSFTNGP09.phx.gbl>,
wi*************@pandora.be says...

What exception?
Your function is expecting an ANSI string, so you should use CharSet.Ansi
And you don't return anything.

Willy.

"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

Hi Ole and the rest,

Have just subscribed to this NG and found this. I have a similar
problem.

I am trying to get a function in C++ DLL to return a string.

Code in DLL is (a portion)

#define WINDLL __declspec(dllexport) CALLBACK
void WINDLL GetName(LPCTSTR szMfr)
{
sprintf((char *)szMfr,"%s",A.Name);
}

"Name" is char array.

Code in C# is

[DllImport("C:\\MyDLL.DLL",
EntryPoint="GetName",CharSet=CharSet.Auto)]
private static extern void GetName(string strName);

This throws an exception

string strName;
GetName(strName);

I am stuck here, obviously. Any ideas as what I am doing wrong, or
alternative methods for passing char arrays back from the DLL to C# as a
string would be welcome.

TIA,

Cheers,

Paul.
In article <u6**************@TK2MSFTNGP12.phx.gbl>, or*@sol.dk says...

HI,
saw the moment I pressed the send button: I forgot the charset option:

[Willy Denoyette [MVP]]

But what is nch.dll?
Your exception is a managed exception indicating a null reference usage.
Need some more code to investigate the problem, please post at least the
code part surrounding the intruction/call that throws.
Also when you intend to pass and return a char* you should pass a
StringBuilder instead of a String
Willy.
"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

Hi Willy,

Thanks for this.

Have already tried CharSet.Ansi. Makes no difference.

The exception is

An unhandled exception of type 'System.NullReferenceException' occurred
in nch.dll

Additional information: Object reference not set to an instance of an
object

Paul.

In article <Oh**************@TK2MSFTNGP09.phx.gbl>,
wi*************@pandora.be says...

What exception?
Your function is expecting an ANSI string, so you should use CharSet.Ansi
And you don't return anything.

Willy.

"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

> Hi Ole and the rest,
>
> Have just subscribed to this NG and found this. I have a similar
> problem.
>
> I am trying to get a function in C++ DLL to return a string.
>
> Code in DLL is (a portion)
>
> #define WINDLL __declspec(dllexport) CALLBACK
> void WINDLL GetName(LPCTSTR szMfr)
> {
> sprintf((char *)szMfr,"%s",A.Name);
> }
>
> "Name" is char array.
>
> Code in C# is
>
> [DllImport("C:\\MyDLL.DLL",
> EntryPoint="GetName",CharSet=CharSet.Auto)]
> private static extern void GetName(string strName);
>
> This throws an exception
>
> string strName;
> GetName(strName);
>
> I am stuck here, obviously. Any ideas as what I am doing wrong, or
> alternative methods for passing char arrays back from the DLL to C# as
> a
> string would be welcome.
>
> TIA,
>
> Cheers,
>
> Paul.
>
>
> In article <u6**************@TK2MSFTNGP12.phx.gbl>, or*@sol.dk says...
>> HI,
>> saw the moment I pressed the send button: I forgot the charset
>> option:

[GingerDeafMan]

nch.dll should have been mydll.dll. They are one and the same. I
simply forgot to rename nch.dll to mydll.dll to match the earlier
posting.

The code that causes the exception is this line

GetManufacturerName(_Name);

_Name is a string.

I am not sure what "null reference usage" means.

Ta for the tip re StringBuilder. Will investigate this.

Paul.
In article <Of**************@TK2MSFTNGP10.phx.gbl>,
wi*************@pandora.be says...

But what is nch.dll?
Your exception is a managed exception indicating a null reference usage.
Need some more code to investigate the problem, please post at least the
code part surrounding the intruction/call that throws.
Also when you intend to pass and return a char* you should pass a
StringBuilder instead of a String
Willy.
"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

Hi Willy,

Thanks for this.

Have already tried CharSet.Ansi. Makes no difference.

The exception is

An unhandled exception of type 'System.NullReferenceException' occurred
in nch.dll

Additional information: Object reference not set to an instance of an
object

Paul.

In article <Oh**************@TK2MSFTNGP09.phx.gbl>,
wi*************@pandora.be says...

What exception?
Your function is expecting an ANSI string, so you should use CharSet.Ansi
And you don't return anything.

Willy.

"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...
> Hi Ole and the rest,
>
> Have just subscribed to this NG and found this. I have a similar
> problem.
>
> I am trying to get a function in C++ DLL to return a string.
>
> Code in DLL is (a portion)
>
> #define WINDLL __declspec(dllexport) CALLBACK
> void WINDLL GetName(LPCTSTR szMfr)
> {
> sprintf((char *)szMfr,"%s",A.Name);

[GingerDeafMan]

GetManufacturerName(_Name) should have been GetName(strName), to follow
the earlier example. Today is definitely not one of my better days :O

But I think we are getting the idea.

GetName(strName) is throwing the exception and I don't know what to do
about this.

Have just tried StringBuilder but still this makes no difference (same
exception thrown).

Paul.
In article <MP************************@news.individual.net> ,
gi*****************@yahoo.co.uk says...

nch.dll should have been mydll.dll. They are one and the same. I
simply forgot to rename nch.dll to mydll.dll to match the earlier
posting.

The code that causes the exception is this line

GetManufacturerName(_Name);

_Name is a string.

I am not sure what "null reference usage" means.

Ta for the tip re StringBuilder. Will investigate this.

Paul.
In article <Of**************@TK2MSFTNGP10.phx.gbl>,
wi*************@pandora.be says...

But what is nch.dll?
Your exception is a managed exception indicating a null reference usage.
Need some more code to investigate the problem, please post at least the
code part surrounding the intruction/call that throws.
Also when you intend to pass and return a char* you should pass a
StringBuilder instead of a String
Willy.
"GingerDeafMan" <gi*****************@yahoo.co.uk> wrote in message
news:MP************************@news.individual.ne t...

Hi Willy,

Thanks for this.

Have already tried CharSet.Ansi. Makes no difference.

The exception is

An unhandled exception of type 'System.NullReferenceException' occurred
in nch.dll

Additional information: Object reference not set to an instance of an
object

Paul.

In article <Oh**************@TK2MSFTNGP09.phx.gbl>,
wi*************@pandora.be says...
> What exception?
> Your function is expecting an ANSI string, so you should use CharSet.Ansi