我有一个磁条卡读取器,它使用键盘输入来发送数据。我正在使用KeyDown事件,在其中获取此对象(C# WPF):
KeyEventArgs e
我希望将获得的键合并成一个字符串。我尝试使用e.Key.ToString()
进行连接,但这并不起作用。我的输入中有很多数字和符号(如;? =等),而e.Key.ToString()
无法正常工作(它会给我一个数字的D3,以及SHIFT或CTRL +另一个键的符号)。
我只想要字符串,因此当我使用例如Console.WriteLine时,我会得到像这样的东西
;51895401051=000001341?
而不是
Oem1SHIFTD1CNTRLD2D3D2D1SHIFTD9OemQuestion ....
我尝试使用KeyConverter,但是我无法弄清楚这个问题。
有人可以帮助我吗?
我的当前事件处理程序(不能正常工作)如下:
public static void keyPress(Object sender, KeyEventArgs e)
{
string keyCodeString = e.Key.ToString();
char? key = null;
if (keyCodeString.Length == 1)
{
key = keyCodeString[0];
}
else
{
if (keyCodeString.StartsWith("NumPad"))
{
key = keyCodeString[keyCodeString.Length - 1];
}
else if (keyCodeString.StartsWith("D"))
key = keyCodeString[keyCodeString.Length - 1];
}
TypedText += key;
}
当TypedText是我想要连接键的字符串时。输出结果如上所述。
我自己解决了它。下面的GetCharFromKey
函数获取一个键(应该发送e.Key)并返回一个字符:
public enum MapType : uint
{
MAPVK_VK_TO_VSC = 0x0,
MAPVK_VSC_TO_VK = 0x1,
MAPVK_VK_TO_CHAR = 0x2,
MAPVK_VSC_TO_VK_EX = 0x3,
}
[DllImport("user32.dll")]
public static extern bool GetKeyboardState(byte[] lpKeyState);
[DllImport("user32.dll")]
public static extern uint MapVirtualKey(uint uCode, MapType uMapType);
[DllImport("user32.dll")]
public static extern int ToUnicode(
uint wVirtKey,
uint wScanCode,
byte[] lpKeyState,
[Out, MarshalAs(UnmanagedType.LPWStr, SizeParamIndex = 4)]
StringBuilder pwszBuff,
int cchBuff,
uint wFlags);
public static char GetCharFromKey(Key key)
{
char ch = ' ';
int virtualKey = KeyInterop.VirtualKeyFromKey(key);
byte[] keyboardState = new byte[256];
GetKeyboardState(keyboardState);
uint scanCode = MapVirtualKey((uint)virtualKey, MapType.MAPVK_VK_TO_VSC);
StringBuilder stringBuilder = new StringBuilder(2);
int result = ToUnicode((uint)virtualKey, scanCode, keyboardState, stringBuilder, stringBuilder.Capacity, 0);
switch (result)
{
case -1:
break;
case 0:
break;
case 1:
{
ch = stringBuilder[0];
break;
}
default:
{
ch = stringBuilder[0];
break;
}
}
return ch;
}