将KeyDown键转换为一个字符串C＃

Question

I have magnetic card reader, It emulates Keyboard typing when user swipes card. I need to handle this keyboard typing to one string, when my WPF window is Focused. I can get this typed Key list, but I don't know how to convert them to one string.

private void Window_KeyDown(object sender, KeyEventArgs e)
{
   list.Add(e.Key);
}

EDIT : Simple .ToString() method not helps. I've tried this already.

Answer 1

Rather than adding to a list why not build up the string:

private string input;

private bool shiftPressed;

private void Window_KeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.LeftShift || e.Key == Key.RightShift)
    {
        shiftPressed = true;
    }
    else
    {
        if (e.Key >= Key.D0 && e.Key <= Key.D9)
        {
            // Number keys pressed so need to so special processing
            // also check if shift pressed
        }
        else
        {
            input += e.Key.ToString();
        }
    }
}

private void Window_KeyUp(object sender, KeyEventArgs e)
{
    if (e.Key == Key.LeftShift || e.Key == Key.RightShift)
    {
        shiftPressed = false;
    }
}

Obviously you need to reset input to string.Empty when you start the next transaction.

Answer 2

...or you can try this:

string stringResult = "";
list.ForEach(x=>stringResult+=x.ToString());

EDIT: After good Timur comment I decided to suggest this:

you can use keyPress event to everything like this:

string stringResult = "";
private void Window_KeyPress(object sender, KeyPressEventArgs e)
{
    stringResult += e.KeyChar;
}

Answer 3

You could have a member variable which is a StringBuilder .

something like

class A
{
    StringBuilder _contents = new StringBuilder();

    private void Window_KeyDown(object sender, KeyEventArgs e)
    {
        _contents.Append(e.Key.ToString());
    }
}

You would have to create a new StringBuilder each time a new card was swiped and then to get the string you would use _contents.ToString();

Answer 4

String combined = String.Empty;

private void Window_KeyDown(object sender, KeyEventArgs e)
{
   combined = combined + e.Key.ToString();
}