GetKeyState函数？ [英] GetKeyState function?

问题描述

为什么在按下方向箭头ON后，函数GetKeyState继续给我一个大于0的值？

  include< iostream> 
 #include< windows.h> 
 using namespace std; 
 
 int main（）
 {
 for（int i = 0; i <1000; ++ i）
 {
 if（GetKeyState VK_UP））
 {
 cout< UP按下< endl; 
} 
 else 
 cout<< UP未按下< endl; 
 
睡眠（150）; 
} 
 
 return 0; 
} 
  

解决方案 http://msdn.microsoft.com/en-gb/library/windows/desktop/ms646301.aspx =nofollow>文档：

< blockquote>

此函数返回的键状态随着线程从其消息队列中读取
键消息而改变。该状态不反映与硬件相关联的
中断级状态。使用
GetAsyncKeyState函数检索该信息。

由于您不处理消息，因此您需要调用 GetAsyncKeyState 。

测试正在按下的键：

$ b b

  if（GetAsyncKeyState（VK_UP）<0）
 //按下键
  
Why after I press the directional arrow ON, the function GetKeyState continues to give me a value greater than 0?
#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
    for(int i = 0; i < 1000; ++i)
    {
        if(GetKeyState(VK_UP))
        {
            cout << "UP pressed" << endl;
        }
        else
            cout << "UP not pressed" << endl;

        Sleep(150);
    }

    return 0;
}

解决方案
From the documentation:

  
The key status returned from this function changes as a thread reads
  key messages from its message queue. The status does not reflect the
  interrupt-level state associated with the hardware. Use the
  GetAsyncKeyState function to retrieve that information.
Since you are not processing messages, you'll want to call GetAsyncKeyState instead.

Test for the key being pressed like this:
if (GetAsyncKeyState(VK_UP) < 0)
    // key is pressed


                        
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