How to convert e.KeyChar to the actual character value when handling keyboard events?

Question

All I want to do is get the actual character, which is pressed whenever the key for the event is entered.

The only option I see is e.KeyChar , which will give me a position, not the character itself.

What I want to do is limit the keypress values ​​to numbers from 0 to 9. The way I'm doing it now is just if((e.KeyChar < 48 || (e.KeyChar > 57)))

It seems a little cheap to just enter the values ​​for 0 and 9, and I would like to know how to get the value of the character, not its key.

EDIT: Thanks for the input; therefore there is generally no way to go from the value of e.KeyChar to the value of the input itself.

I would really like to accept my event, and access the character pressed directly, and not use e.KeyChar to get a numerical representation of this value.

Answer 1

Here is an easier way to determine if the key pressed is a number or not:

 if (char.IsDigit(e.KeyChar)) { // doSomething(); } 

Answer 2

KeyChar is a char value - the character itself - 48 and 57 - is ascii for 0 and 9 .

In C #, you can refer to a character through its numeric ASCII code or the actual character in single quotes. Therefore, your code may become:

 if((e.KeyChar < '0' || (e.KeyChar > '9'))) 

which is exactly the same.

Answer 3

e.KeyChar corresponds to the char corresponding to the key pressed, not to the position .. The .NET Framework uses char to represent the Unicode character. If by "actual value of a character" you mean the integral value of characters 0-9, and not their Unicode values ​​(48-57), you can do this:

 var value = Char.GetNumericValue(e.KeyChar); 

To limit key values, press numbers between 0-9:

 if (!Char.IsDigit(e.KeyChar)) { e.Handled = true; return; } 

For a more complete solution that allows corrections:

 const char Backspace = '\u0008'; const char Delete = '\u007f'; if (!Char.IsDigit(e.KeyChar) // Allow 0-9 && e.KeyChar != Backspace // Allow backspace key && e.KeyChar != Delete) // Allow delete key { e.Handled = true; return; }