C＃-如何检测+和=按下的字符

Question

I was testing keys and I got that = and Shift+= (+) have the same code: 187

And the expression e.KeyValue == 187 works in the both cases. How to verify the real key? Thanks

Answer 1

Examining the documentation for System.Windows.Forms.KeyEventArgs, which it seems you're using here, you'll discover several documented properties which give you "the rest of the story".

What you're interested in is the Shift property. For example:

if ( e.Shift )  { /* the key is + */ }
           else { /* the key is = */ }

Note, too, that just examining the Shift property doesn't account for the possibility that the user has also held down the Alt key, or the Control key, which are reflected similarly in the properties Alt and Control

Also, you may need to understand the Modifiers property, which is a bit field indicating all of the modifier key states (Atl, Control and Shift) at once.

Further, you will want to investigate the difference between KeyValue, KeyCode and KeyData.

KeyValue is defined as a raw numeric value, which as you discovered ignores shift states, so it can't distinquish between lower and upper case, or between + and =.

Answer 2

You can read here that via the event args you can verify if shift is pressed or not, for intense:

if ( e.Shift )  
{ 
   // the key is +  
}
else 
{ 
  //  the key is = 
}