问题
Am I doing this correctly?
[DllImport("user32", CharSet = CharSet.Auto)]
internal static extern long SystemParametersInfo(long uAction, int lpvParam, ref bool uParam, int fuWinIni);
...
public static bool IsScreenReaderRunning()
{
long SPI_GETSCREENREADER = 70L;
bool bScreenReader = false;
long retVal;
retVal = SystemParametersInfo(SPI_GETSCREENREADER, 0, ref bScreenReader, 0);
//uint iParam = 0;
//uint iUpdate = 0;
//bool result = false;
//bool bReturn = SystemParametersInfo(SPI_GETSCREENREADER, iParam, &bScreenReader, iUpdate);
return bScreenReader;
}
public static void ScreenReaderOn()
{
long SPI_GETSCREENREADER = 71L;
bool bScreenReader = true;
long retVal;
retVal = SystemParametersInfo(SPI_GETSCREENREADER, 0, ref bScreenReader, 0);
}
public static void ScreenReaderOff()
{
long SPI_GETSCREENREADER = 71L;
bool bScreenReader = false;
long retVal;
retVal = SystemParametersInfo(SPI_GETSCREENREADER, 0, ref bScreenReader, 0);
}
回答1:
The pinvoke declaration is completely wrong, it was copied from VB6 code. The return type and arguments are not long (the VB6 int32 type), they are int. Pinvoke.net is a decent site to get good declarations.
[DllImport("user32.dll", SetLastError = true)]
static extern bool SystemParametersInfo(int uiAction, int uiParam, IntPtr pvParam, int fWinIni);
Don't forget to throw Win32Exception when you get a false return so failure isn't silent.
回答2:
Based on this article, the last parameter to SystemParametersInfo should be:
int SPIF_SENDCHANGE = 0x02;
When changing the value.
来源:https://stackoverflow.com/questions/5434709/using-systemparametersinfo-from-c-sharp-spi-getscreenreader-spi-setscreenreader