TextBox没有监听在C＃中按空格键之前输入密钥

Question

I have to process an "Enter" key event on text box so I created a new class inheriting from textBox and have already overridden the IsInputKey method. Problem is the KeyDown event is not being fired with out pressing the space bar first.

public class EnterTextBox : TextBox
{
    protected override bool IsInputKey(Keys keyData)
    {
        if (keyData == Keys.Enter)
        {
            return true;
        }
        else
        {
            return base.IsInputKey(keyData);
        }
    }
}

After creating from the above class as

EnterLisTextBox enterTextBox1 = new EnterLisTextBox();            
enterTextBox1.KeyDown += enterTextBox1_KeyDown;

the key down event handler is

void enterTextBox1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter)
    {
        MessageBox.Show("Pressed enter");;
    }  
}

But this only works if I pressed the "Space bar" before using the "Enter key". But once i pressed the space bar even if I retype every thing on the text box it works. Why is this? Why is it the prerequisite to press the space bar?

UPDATE:

Implementing keyPress event worked for me, but if any one has any idea why the above not worked before using the sapce bar. This is the how i used keypress, note the e.KeyChar == '\\r'

void enterTextBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == '\r')
    {
        MessageBox.Show("Pressed enter");
    }  
}

Answer 1

I guess that the enter key does not count as "normal" key in this event, so you have to explicitly make it an input key in the PreviewKeyDown event method:

    private void enterTextBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
    {
        switch (e.KeyCode)
        {
            case Keys.Down:
                e.IsInputKey = true;
                break;
            case Keys.Up:
                e.IsInputKey = true;
                break;
            case Keys.Enter:
                e.IsInputKey = true;
                break;
        }
    }

This is also true for the arrow keys, for example. And of course, your textbox needs to have the focus first.

Answer 2

First you have to select TextBox and then you have to press enter key ,otherwise KeyDown Event on Textbox won't be fired.

Coming to your case when you press Spacebar your textbox is getting the focus/being selected hence there after your textbox is able to handle enter key event.