.net c# webservice to PB dll

[jeroen brouwers]

Hi

I hope someone can help me solve this riddle with c#.
I'm trying to write a webservice that calls a PB dll (v8.04).

My dll (besides a clean LibMain) is this:

FUNCTION Test1 ALIAS "TEST1" ( ProjectID AS LONG, sVar AS STRING ) EXPORT AS LONG

    FUNCTION = LEN( sVar )

END FUNCTION  

FUNCTION Test2 ALIAS "TEST2" ( ProjectID AS LONG, sVar AS STRING * 255 ) EXPORT AS LONG

    FUNCTION = LEN(TRIM$( sVar ))

END FUNCTION

I'm trying to find out how to pass a string the proper way.

In my c# webservice, I have the following declarations and webmethod:

    [DllImport("test.dll", EntryPoint = "TEST1", SetLastError = true, CharSet = System.Runtime.InteropServices.CharSet.Auto)]
    private static extern int test1(
        int projectid,
        [MarshalAs(UnmanagedType.AnsiBStr,SizeConst=255)]
        string sVar
    );

    [DllImport("test.dll", EntryPoint = "TEST2", SetLastError = true, CharSet = System.Runtime.InteropServices.CharSet.Auto)]
    private static extern int test2(
        int projectid,
        [MarshalAs(UnmanagedType.AnsiBStr,SizeConst=255)]
        string sVar
    );

    [WebMethod]
    public int RunTest1(string sVar)
    {
        try
        {
            return test1(1, sVar);
        }
        catch (Exception ex)
        {
            return -1;
        }
    }

    [WebMethod]
    public int RunTest2(string sVar)
    {
        try
        {
            return test2(1, sVar);
        }
        catch (Exception ex)
        {
            return -1;
        }
    }

What I get back is always 255, even I just enter a sVar of just 4 characters. Extracting on Chr$(0) doesn't help either.

I've tried playing with leaving the SizeConst in the webdeclaration and AnsiBStr and I just cannot figure out what I'm doing wrong here.



What I want to archieve in the end is how to pass a pointer (of a string or a struct):

Additional function in PB

FUNCTION Test3 ALIAS "TEST3" ( ProjectID AS LONG, BYVAL  sVar AS STRING PTR ) EXPORT AS LONG

    FUNCTION = LEN(TRIM$( @sVar ))

END FUNCTION

Additional stuff in the webservice:

[DllImport("test.dll", EntryPoint = "TEST3", SetLastError = true, CharSet = System.Runtime.InteropServices.CharSet.Auto)]
    private static extern int test3(
        IntPtr sVar
    );


public int RunTest3(string sQuestion)
    {
        try
        {
            IntPtr s = Marshal.StringToHGlobalAnsi(sQuestion);

            int result = test3(1, ref s);

            Marshal.FreeHGlobal(s);

            return result;
        }
        catch (Exception ex)
        {
            return -1;
        }
    }

This doesn't work at all.. At least I cannot get it to work.


Hope someone can give me tip on where to go with this.

Many regards

Jeroen Brouwers

[Michael Mattias]

The StringToHGlobalAnsi method might be returning a Ptr to an ASCIIZ string rather than a "STRING" string. (OLE string).

In which case you just have to change the procedure header in your PB function to either "[BYREF] sz AS ASCIIZ" or "BYVAL psz AS ASCIIZ PTR"

Worth a try anyway.