使用 C# 中的 SystemParametersInfo (SPI_GETSCREENREADER SPI_SETSCREENREADER)

Question

我这样做正确吗？

[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);
}

Answer 1

pinvoke 声明是完全错误的，它是从 VB6 代码复制而来的。返回类型和参数不长（VB6 int32 类型），它们是int。Pinvoke.net 是一个不错的网站，可以获得良好的声明。

[DllImport("user32.dll", SetLastError = true)]
static extern bool SystemParametersInfo(int uiAction, int uiParam, IntPtr pvParam, int fWinIni);

不要忘记在得到错误返回时抛出 Win32Exception，这样失败就不会消失。