C# Can'；找不到PInvoke DLL错误

我尝试使用进度条在MC3190Z中引用Locate标记，并希望显示进度条值随声音的变化。现在只使用摩托罗拉示例代码来播放声音。但声音只有一声嘟嘟

m_LocateForm.Locate_PB.Value = tagDataArray[nIndex].LocationInfo.RelativeDistance; 

m_LocateForm.lastLocatedTagTimeStamp = System.Environment.TickCount; 

if (m_LocateForm.Locate_PB.Value >0) 
{ if (m_isBeepingEnabled) MessageBeep(MB_OK); }

想让它看起来好像标签更近了，所以进度条值很高，声音应该像快速的哔哔声。所以，当标签距离较远时，进度条较低，声音只是缓慢的嘟嘟声

我是否需要放置两种类型的声音来显示声音的变化

目前我的代码是

[DllImport("coredll.dll")]
internal static extern bool Beep(uint dwFreq, uint dwDuration);

if (m_isBeepingEnabled)
Beep(Convert.ToUInt32(m_LocateForm.Locate_PB.Value), 150);

但它显示错误无法找到PInvoke DLL，您可能需要尝试

使用以下标志定义

public enum PlaySoundFlags : uint {
    SND_SYNC = 0x0,            // play synchronously (default)
    SND_ASYNC = 0x1,            // play asynchronously
    SND_NODEFAULT = 0x2,        // silence (!default) if sound not found
    SND_MEMORY = 0x4,            // pszSound points to a memory file
    SND_LOOP = 0x8,            // loop the sound until next sndPlaySound
    SND_NOSTOP = 0x10,            // don't stop any currently playing sound
    SND_NOWAIT = 0x2000,        // don't wait if the driver is busy
    SND_ALIAS = 0x10000,        // name is a registry alias
    SND_ALIAS_ID = 0x110000,        // alias is a predefined ID
    SND_FILENAME = 0x20000,        // name is file name
    SND_RESOURCE = 0x40004,        // name is resource name or atom
};

public enum PlaySoundFlags : uint {
    SND_SYNC = 0x0,            // play synchronously (default)
    SND_ASYNC = 0x1,            // play asynchronously
    SND_NODEFAULT = 0x2,        // silence (!default) if sound not found
    SND_MEMORY = 0x4,            // pszSound points to a memory file
    SND_LOOP = 0x8,            // loop the sound until next sndPlaySound
    SND_NOSTOP = 0x10,            // don't stop any currently playing sound
    SND_NOWAIT = 0x2000,        // don't wait if the driver is busy
    SND_ALIAS = 0x10000,        // name is a registry alias
    SND_ALIAS_ID = 0x110000,        // alias is a predefined ID
    SND_FILENAME = 0x20000,        // name is file name
    SND_RESOURCE = 0x40004,        // name is resource name or atom
};