VB.NET Fixed String with embedded null characters

[JKAT]

Hi All,

I am using a com object to maniplate data inside an external program using VB.NET. One of the methods this com object provides requires 1 string parameter.

The external program, however, requires a sting of a specified length, regardless of the number of characters used. The string to be passed to the function (length 36) is a combination of the below key fields.

keyfield 1 length = 2
keyfield 2 length = 7
keyfield 3 length = 10
keyfield 4 length = 6
keyfield 5 length = 14

If the actual value assigned to keyfield 2 has a length less than 7, it should be padded to the right with null characters.

If the actual value assigned to keyfield 3 has a length less than 10, it should be padded to the right with null characters.

If I have the following values:

1: "00"
2: "11111"
3. "123"
4: "XXXXXX"
5: "YYYYYYYYYYYYYY"

I would need the actual values :

keyfield 1 value = "00"
keyfield 2 value = "11111" + chr(0) + chr(0)
keyfield 3 value = "123" + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0)
keyfield 4 value= "XXXXXX"
keyfield 5 value = "YYYYYYYYYYYYYY"

Which, when concatenated, would result in the below key to be passed to com object method:
"0011111 123 XXXXXXYYYYYYYYYYYYYY"

Using a standard .NET string, the first null character (chr(0)) is interpreted as a terminator and the balance of the string is gone.

I have tried the VB6 compatability's VBFixedString type but the com object's method throws an exception due to a type mismatch.

If I convert the VBFixedString back to a .NET string before passing it to the method, the first null character is again interpreted as a string terminator and the rest of my string is chopped.

Does anyone know if there is a way to get around this problem? Any help would be greatly appreciated.

[Frinavale]

Well, in general (C#, C++, Java, C etc etc) Strings are terminated using a null character.

It doesn't make any sense to pad a string with null characters.


Are you certain that you aren't supposed to just pad with space?