Develop Reference

Capturing Enter Key press on windows form not working

I have a user authentication form with username and password textboxes.There is an okay button that fires the code to validate the credentials.
I want the same code to get executed when the user hits Enter key anywhere on the form.
So i register for the keypress event like this
this.KeyPress += UserLogin_KeyPress;
private void UserLogin_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)13)
{
MessageBox.Show("enter");
}
}
This event is not triggered at all.What i'm i doing wrong?

Try setting the property keypreview to true and changing to keydown instead since KeyPress don't support e.Keycode:
private void UserLogin_KeyPress(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
MessageBox.Show("Enter");
}
}

Try this:
private void UserLogin_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
MessageBox.Show("enter");
}
}

As mentioned, set form.KeyPreview = true so that most key events will be given to the form before the controls.
However, note that this doesn't always work, and some controls will still "steal" certain key presses anyway. For example, if a Button has focus, then an Enter keypress will be used by the button to activate it, before you get a chance to see it, and since it counts as having been "handled", you never get to see the keypress.
The workaround I use for this is to set focus to something that I know will not steal the enter key press, for key presses that occur leading up to the enter key press. So, if the pressed keys are <1><2><3><4><ENTER> then the 1-4 keys all set focus to something that is not a button (usually, the textbox where I am displaying the resulting text), and then when <ENTER> is pressed, it should make it to your form's event handler (as long as KeyPreview == true).

It's only looking at the form. Controls on the form also need to be wired in.

Keyboard shortcuts in Windows Forms

I want to use the combination Alt+X to close the current form, but there is also one condition: if the user presses a similar combination like Alt+X,C, it shouldn't work.

The form/control has an event called key press and key down. In the properties window input 'Form1_KeyPress'. This will run the method below
void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == //KeyCode for alt && e.KeyChar == //KeyCode for x)
{
//run code here
}
}

keydown to correspond with button down

Hello I am trying to match the button down visual (on the WinForm, the button boarder gets a little darker, indicating it is pressed) with a keydown event. First of all I need to detect a keydown for numbers only. Then when the key goes down, the corresponding number button on the form should look like it is depressed as well. Sorry if this is already been answered using differt jargon. I already know how to perform a button click with the keydown.

Make a test code on KeyDown event. Write down the keyboard codes you shall see from pressing 0 to 9. Then use those keyboard codes in your KeyDown's if statement

You can use a Checkbox and set the appearance to be Button. Then you can do something like this:
private void OnKeyDown(object sender, KeyEventArgs e)
{
//if key
checkBox1.Checked = true;
}
private void OnKeyUp(object sender, KeyEventArgs e)
{
//if key
checkBox1.Checked = false;
}
As far as the Keys, you can just use the KeyEventArgs.KeyCode
e.KeyCode == Keys.D0 || .. || e.KeyCode == Keys.D9

Detect Key in KeyUp event

I have a textbox on a form where I'm trying to detect the keys the user types in. The TextBox is multilined with wordwrap on. I don't want the user the press the enter key (as I want all text entered on ONE line, wrapped) so I used the following code:
private void txtPlain_KeyPress(object sender, KeyPressEventArgs e) {
if (e.KeyChar == (char)13) {
MessageBox.Show("Enter keys are not allowed");
e.KeyChar = (char)0;
}
}
This worked fine in my tests, but when I tested for CTRL+ENTER it didn't work as I'm not sure how to detect for the control key. From my googling I found that I need to use the KeyUp/Down events so I now have the following Code:
private void txtPlain_KeyUp(object sender, KeyEventArgs e) {
//if (e.KeyData == (Keys.Control | Keys.Enter)) {
if (e.KeyCode == Keys.Enter || (e.KeyCode == Keys.Enter && e.Control)) {
MessageBox.Show("Enter keys are not allowed:");
//e.KeyValue = Keys.None;
}
}
The first commented out line didn't work for some reason so if anyone could explain why this would be useful.
The problem with the KeyUp/Down event is that I don't know how to REMOVE the enter key from the text - unlike the KeyPress event when I can set the KeyChar to zero. The event captures both the Enter and Ctrl+Enter keys, but the cursor still goes to the next line in the TextBox.
Thanks for any help on this.

Hmm, there's no reason to disallow the Enter key by handling the KeyDown or KeyUp events. You can simply set the AcceptsReturn property of the textbox control to False. This will prevent a multiline textbox from responding to a press of the Enter key.
Of course, this doesn't solve the problem of Ctrl+Enter. In fact, that's the expected way to create a new line when the AcceptsReturn property is set to False. To solve that, you will need to handle one of the keyboard events and prevent the control from receiving this input.
KeyDown is a good place to start. What you want to do is filter out any keyboard events that include the Keys.Enter flag. That will catch them no matter which other modifier key they might be combined with. Then, once you've found an Enter keypress, you want to set the e.Handled property to True in order to prevent it from being passed on to the control.
But unfortunately, we're not quite done yet. The textbox control tries to handle certain keys internally, and you're not going to be able to override that in a key event handler method. You also need to tell the control not to interpret that particular key as an input key. There are two primary ways of doing this. The first (and recommended way) is to inherit from the base TextBox class to create your own custom control, and then override the protected IsInputKey method. The second (somewhat simpler) way is just to handle the PreviewKeyDown event, and set the IsInputKey property to False.
Sample code:
private void txtPlain_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
// Check if the KeyCode value has the Keys.Enter flag set
if ((e.KeyCode & Keys.Enter) == Keys.Enter)
{
// Set the IsInputKey property to False
e.IsInputKey = false;
}
}
private void txtPlain_KeyDown(object sender, KeyEventArgs e)
{
// Check if the KeyCode value has the Keys.Enter flag set
if ((e.KeyCode & Keys.Enter) == Keys.Enter)
{
// Show the user a message
MessageBox.Show("Enter keys are not allowed in this textbox.");
// Prevent the key event from being passed on to the control
e.Handled = true;
}
}
And, though I assume this is for testing purposes only, you definitely want to take that MessageBox call out of there for production code. Find another way to alert the user that their input was not allowed, such as a short beep sound and an ErrorProvider component placed next to the textbox. Showing a message box is very jarring, and not very user-friendly. See my answer here for other hints and tips.

private void txtPlain_KeyUp(object sender, KeyEventArgs e) {
//if (e.KeyData == (Keys.Control | Keys.Enter)) {
if (e.KeyCode == Keys.Enter || (e.KeyCode == Keys.Enter && e.Control)) {
MessageBox.Show("Enter keys are not allowed:");
//e.KeyValue = Keys.None;
// mark event as handled
e.Handled = true;
}
}
from msdnlink
edit:
I think that you need the key down event not the key up
EDIT2
here is some tested code and it works as you wanted:
bool invalid=false;
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
if ((e.KeyCode & Keys.Enter) == Keys.Enter)
{
invalid = true;
}
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (invalid)
{
e.Handled = true;
}
invalid = false;
}

The first commented out line didn't work for some reason so if anyone could explain why this would be useful.
You wanted to detect Ctrl + Enter.
if (e.KeyData == (Keys.Control | Keys.Enter)) {..
Keys.Control and Key.Enter are nothing but are some values please refer . Now doing logical or will not necessarily result to key which has been pressed. Totally illogical clause.
Ok now come to your actual problem you want to detect Enter stroke and Ctrl + Enter stroke to be treated as same.
Besides you want to undo the newline character thats been introduced. Try
PreviewKeyDown or Preview key up eventhandler with the following condition
if(e.KeyCode==Keys.Enter)
Let me know if this works

C# KeyEvent doesn't log the enter/return key

I've been making this login form in C# and I wanted to 'submit' all the data as soon as the user either clicks on submit or presses the enter/return key.
I've been testing a bit with KeyEvents but nothing so far worked.
void tbPassword_KeyPress(object sender, KeyPressEventArgs e)
{
MessageBox.Show(e.KeyChar.ToString());
}
The above code was to test if the event even worked in the first place.
It works perfectly, when I press 'd' it shows me 'd' when I press '8' it shows me '8' but pressing enter doesn't do anything.
So I though this was because enter isn't really bound to a character but it did show backspace, it worked just fine so it got me confused about why it didn't register my enter key.
So the question is:
How do I log the enter/return key? and why doesn't it log the key press right right now like it should?
note: I've put the event in a textbox
tbPassword.KeyPress += new KeyPressEventHandler(tbPassword_KeyPress);
So it fires when the enter button is pressed WHILE the textbox is selected (which is was the whole time of course) maybe that has something to do with the execution of the code.

Do you have a button defined as the default action?
If so then that control will gobble up the Enter key.
And maybe that is your answer. You need to set the DefaultAction property to true on your submit button.

Try the KeyDown event instead.
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
MessageBox.Show("Enter");
}
}

Perhaps you should use the "AcceptButton" of the form to set it to the submit button. Think that is what you what really...

You have left out a vital bit, you must set the Handled property to true or false depending on the condition...
void tbPassword_KeyPress(object sender, KeyPressEventArgs e)
{
MessageBox.Show(e.KeyChar.ToString());
if (e.KeyCode == Keys.Enter){
// This is handled and will be removed from Windows message pump
e.Handled = true;
}
}

Try this
textBox1.KeyPress += new KeyPressEventHandler(textBox1_KeyPress);
void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == '\r')
{
MessageBox.Show("Enter Key Pressed", "Enter Key Pressed", MessageBoxButtons.OK);
}
}

go to your forms...
in the basic form change this
FormName.AcceptButton = buttonName;
this would read the key log file of enter... automatically..
you can do this if you dont want users to see accept button
buttonName.Visible = false;
FormName.AcceptButton = buttonName;
AcceptButton automatically reads the enter key from the keyboard