I keep getting an error while trying to pass a specific struct to a
PInvoked method.
The error code returned when calling Marshal.GetLastWin32Error() is
0x06F8.
I'm trying to consume the setupapi function
SetupDiGetDeviceInstallParams.
The problematic struct is SP_DEVINSTALL_PARAMS.

I found this in winerror.h as
#define ERROR_INVALID_USER_BUFFER 1784L

and a call to

System.ComponentModel.Win32Exception(0x06F8);

gives me this further information, "The supplied buffer is not valid
for the requested operation."

Since I couldn't figure out the size of the struct that the function is
expecting,
I decided to put the function call into a while loop initially setting
the struct's cbSize value to 0x0000 and increment it by 0x0001 after
each call to PInvoke function. Calling the function w/ the struct's
cbSize value ranging from 0x0000 to 0x10000, I still get the same exact
result. Always 0x06F8.

I dug deeper into the API's source code and saw that this error value
is only set in one place, where it compares the the passed in struct's
cbSize with sizeof(SP_DEVINSTALL_PARAMS). You'd figure I get a
successful hit trying each size value from 0x0000 to 0x10000 ! I'll try
it again w/ all possible that'll fit in a DWORD in hope to eliminate
the passing in the wrong size issue.

Any ideas anyone??
Has anyone used this API much with C# via PInvoke?

Thanks,

-ks