public static extern UInt32 PdhExpandWildCardPathW(
string szdataSource,
string szWildCardPath,
IntPtr mszExpandedPathList,
ref long pcchPathListLength,
PdhExpansionFlags dwFlags);
private List <string> ExpandCounterPath(string searchPattern, PdhExpansionFlags flags)
{
long cchPathListLength = 0;
uint result = 0;
byte[] buffer = null;
//
// Do - while, the buffer can grow after being told the necessary size
do
{
IntPtr mszExpandedPathList = IntPtr.Zero;
if (cchPathListLength > 0)
{
//
// If we received a buffer size allocate one
// Unicode size is 2 bytes
mszExpandedPathList = Marshal.AllocHGlobal(2 * (int)cchPathListLength);
}
try {
result = Pdh.PdhExpandWildCardPathW(null, searchPattern, mszExpandedPathList, ref cchPathListLength, flags);
if (result == Pdh.PDH_MORE_DATA)
{
continue;
}
if (result == Pdh.PDH_CSTATUS_NO_OBJECT || result == Pdh.PDH_CSTATUS_NO_INSTANCE)
{
return(new List <string>());
}
if (result != 0 && result != Pdh.PDH_MORE_DATA)
{
throw new Win32Exception((int)result);
}
buffer = new byte[cchPathListLength * 2];
Marshal.Copy(mszExpandedPathList, buffer, 0, buffer.Length);
}
finally {
//
// Always clean up allocated buffer
if (mszExpandedPathList != IntPtr.Zero)
{
Marshal.FreeHGlobal(mszExpandedPathList);
}
}
} while (result == Pdh.PDH_MORE_DATA);
if (buffer == null)
{
throw new Win32Exception((int)result);
}
//
// Parse paths from filled buffer
List <string> strings = new List <string>();
int start = 0;
int end = 0;
var chars = Encoding.Unicode.GetChars(buffer);
do
{
do
{
end++;
}while (end < chars.Length && chars[end] != 0);
strings.Add(new string(chars, start, end - start));
start = end;
} while (start < chars.Length - 1 && chars[start + 1] != 0);
return(strings);
}
