Isletter on datagrid keydown event

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I am attempting to break down user input onto a KeyDown event on a DataGrid by working out whether their input is a letter or a number.

The method I am using at the moment performs bizzarely. Firstly, the IsDigit never happens and clearly is not working. Secondly the IsLetter works, but only on some letters (W,Z,X,V and Y). There must be a more comprehensive way of doing this as this clearly is not working for me.

What I have tried:

This is the method I am using so far;

private void OnDataGridKeyDown(object sender, KeyEventArgs e)
{
   if (char.IsLetter(Convert.ToChar(e.Key)))
   {
        MessageBox.Show("Letter");
   }
   if (char.IsDigit(Convert.ToChar(e.Key)))
   {
        MessageBox.Show("Number");
   }
}

Posted 6-Sep-16 22:47pm

DRD94

Updated 7-Sep-16 0:01am

Richard MacCutchan

v2

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Richard MacCutchan 7-Sep-16 5:23am

Convert.ToChar does not work on key values. ~~You also need to look at the documentation for KeyEventArgs, which does not list a property named Key.~~
Thanks to Griff for setting me right.

OriginalGriff 7-Sep-16 5:33am

The WPF version does - and DataGrid is a WPF control.

Richard MacCutchan 7-Sep-16 5:38am

Curse you Microsoft.

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OriginalGriff · Accepted Answer · 2016-09-06T23:30:00

Convert.ToChar does not have an overload which explicitly takes a Key value, so quite what it will produce I'm not certain. It's unlikely to convert Key.A to 'A', Key.B to 'B' and so forth.
In fact, I just checked:

C#

System.Windows.Input.Key k = System.Windows.Input.Key.A;
for (int i = 0; i < 26; i++)
    {
    char c = Convert.ToChar(k);
    Console.WriteLine("{0}:{1}", k, c);
    k++;
    }

And it doesn't:

A:,
B:-
C:.
D:/
E:0
F:1
G:2
H:3
I:4
J:5
K:6
L:7
M:8
N:9
O::
P:;
Q:<
R:=
S:>
T:?
U:@
V:A
W:B
X:C
Y:D
Z:E

What you need to do is:

C#

Key k = e.Key;
if (k >= Key.A && k <= Key.Z)
    {
    ...
    }
if ((k >= Key.D0 && k <= Key.D9) || (k >= Key.NumPad0 && k <= Key.NumPad9))
    {
    ...
    }