Is there a way to start a method in C# if a key is pressed? For example, Esc?
use the OnKeyPress Event of your textbox and in the event
if(e.KeyCode==Keys.Escape)
{
yourTextBox.Text = string.Empty;
}
As others have mentioned, handle the KeyDown or KeyUp event of the appropriate control. The KeyPress event would work for the Escape key as well, though it will not trigger for some keys, such as Shift, Ctrl or ALt.
If you want to execute this function anytime the user presses the Escape key, then you probably want to handle the event on the Form. If you do this, you will probably also want to set the Form's KeyPreview property to true. This will allow the Form control to receive the event even if the focus is currently inside of one of the child controls.
If you want the behavior to be specific to a control, such as clearing the text within a textbox that currently has focus, then you should handle the KeyDown or KeyUp event of the TextBox control. This way, your event handler will not be triggered if the user presses the escape key outside of the textbox.
In some situations you might want to prevent child controls from handling the same event that you've just handled. You can use the SuppressKeyPress property on the KeyEventArgs class to control this behavior:
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Escape)
{
MessageBox.Show("Escape key pressed");
// prevent child controls from handling this event as well
e.SuppressKeyPress = true;
}
}
In case someone is looking for how to do this in a console application
if (Console.ReadKey().Key == ConsoleKey.Escape)
{
return;
}
I am writing WinForms application. User fills the textbox and if he wants to delete everything, he just clicks esc key on keyboard
I think you need to handle the KeyDown event.
You have to switch the form property "KeyPreview" to true or your events will not be fired. Handling these events alone will not do anything even though the events are correct. It will look to you like nothing really happens even though you have subscribed the proper event handlers.
First in Properties do > KeyPreview : True
Then :
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Escape)
{
//call your method here
}
}
Are you writing a Console application, a WinForms application or something else? Are you trying to capture the ESC key at all times (regardless of the focused window/application) or something else?
More context required.
If you're writing a Console app, then you should start looking at things like Console.ReadKey...
http://msdn.microsoft.com/en-us/library/system.console.readkey.aspx
With Event KeyPress...
//Escape
if (e.KeyChar == '')
{
this.DialogResult = DialogResult.Cancel;
e.Handled = true;
}
You can use KeyUp event too. I prefer it though.
private void Window_KeyUp(object sender, System.Windows.Input.KeyEventArgs e) {
if (e.Key == Key.Escape) {
//WHAT WILL HAPPEN INSERT HERE
}
}
The basic answer is listed here several time
Implement Form_KeyDown
Private Sub frmCustomerSearch_KeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown
Try
If e.KeyCode = Keys.Escape Then
ClearFindForm()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Set form.keyPreview
form.KeyPreview = true
The additional thing you need to check is whether you have a button capturing ESC so it can be the form.cancelButton
to be sure ...
form.CancelButton = nothing
This is sneaky. If you have set that and forgot about it, the Escape key will not trigger the KeyDown event.
I was led to this because a button set to be the form.CancelButton does not seem to fire if it is invisible or on a non visible tab,so KEYDOWN is your only option.
Related
I am developing a small application with some buttons and textbox. What I am having problem is assigning a keyboard key (e.g. F3) to a button click.
For example if the user click the button Cash the code I wanted it's executed fine, but I want to make more easier instead clicking the button with mouse, I want the user be able to press the key on keyboard. I used the keydown event, also keypress event of that button, but still nothing.
I tried this keydown event
if (e.KeyCode == Keys.Enter)
{
btncash.PerformClick()
}
But still nothing
Do not use F3 function button it's used by OS for activating search. Enter key is fairs click event on focused control so do not use this also. Implement as suggested below.
In your Main form
Set KeyPreview to True in form load event.
Add KeyDown event handler with the following code
private void Form1_KeyDown(object sender,
KeyEventArgs e)
{
if (e.Control && e.KeyCode == Keys.H)
{
btncash.PerformClick();
//btncash_Click(null, null);
}
}
I have a winforms application where in I have a textbox inside a form. I need to set focus to the textbox whenever I press 'Ctrl+F'. I have the following code in keyup event.
private void frm_KeyUp(object sender, KeyEventArgs e)
{
// Handle 'Ctrl + F' to Find
if (e.KeyData == (Keys.Control | Keys.F))
SetFocus();
}
Problem I have here is that sometimes, even though the focus is on form and I try 'Ctrl+F' the condition doesn't run. I know, as soon as I press 'Ctrl' the event gets fired even before I would have pressed key 'F'. Eventually it works, when I press both the keys at the very same time. So to the user it might look like the screen is unresponsive to the keys sometimes.
How can I overcome this situation?
You're using the KeyUp event and checking if the event contains both keys. This will only happen when you release both keys at the same time.
Change it to the KeyDown event instead, and check whether Ctrl was pressed at the moment F was pressed:
if (e.Control && e.KeyCode == Keys.F)
{
// ...
}
Steps to reproduce in VS Express 12:
Create a new Windows Forms Application project
Add a button
Set the Form KeyPreview to true
Add a keyDown event to the form
The event will not trigger as long as the button is present on the form
I have a project where I want to catch both keydown and keyup events, however, I can only seem to get the keyup event to work.
I have a form with a single panel, button and label on it. In the form the keyPreview property is set to true, and is linked to both the KeyDown and KeyUp events.
However, when I run the program, only the KeyUp event triggers.
I tried adding the event handlers manually by adding
this.KeyPreview = true;
this.KeyDown += new KeyEventHandler(Form1_KeyDown);
But it still does not work.
Any suggestions?
KeyUp event:
private void Form1_KeyUp(object sender, KeyEventArgs e)
{
TriggerKey(e.KeyCode, false);
}
private void TriggerKey(Keys e, Boolean pKeyDown)
{
switch (e)
{
case Keys.Left:
mLeft = pKeyDown;
break;
case Keys.Right:
mRight = pKeyDown;
break;
case Keys.Down:
mDown = pKeyDown;
break;
case Keys.Up:
mUp = pKeyDown;
break;
}
}
My Form1_KeyDown event looks like this:
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
TriggerKey(e.KeyCode, true);
}
Edit2:
I've tried removing the button from my form, and then both events trigger correctly. If I add it back in, the keyDown event stops working again. Why is the button interfering when the keypreview property is set?
KeyPreview is a VB6 compatibility feature, it isn't "native" Winforms. And it has a problem that exactly matches your issue. There are other Form methods that get a sniff at the keystroke first, before the code that looks at KeyPreview gets a chance to run and fire the KeyDown event. And they eat the navigation keystrokes first. Like the cursor keys that you are trying to see as well as the Tab key. This matches the VB6 behavior, it also couldn't see the cursor keys.
To stay ahead of that code, you'll need to override the ProcessDialogKey() method of the form. Like this:
protected override bool ProcessDialogKey(Keys keyData) {
switch (keyData) {
case Keys.Left:
//...
return true;
}
return base.ProcessDialogKey(keyData);
}
you're setting mUp on keyDown...? can you add all the related code context such as the mouse up event, also you may try to refresh, if you break does the even fire on key down?
Note that keyup is raised after keydown(if you want your mUp to remain true)
I saw in other similar posts that this could help
this.focus();
give it a try and let me know to keep looking for other ways
Basically in a C# Windows Form Application I am working on I have 2 buttons I press button1 and button2.
How do I make it when I press 2 custom keys simultaneously(eg. CTRL+L) the program does the steps coded for button1? Keeping in mind that the window might not be active.
I have looked at this: Keypress To Simulate A Button Click in C# but I don't think this would work if the window isn't active, and its also only one button pressed not two.
In Form KeyUp Event and the Properties is KeyPressPreview = true you can achieve this task.
private void Form_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.L && e.Control)
{
yourButton.PerformClick();
e.Handled = true;
}
}
or
if you want in Keypress Event
private void Form_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.Control && e.KeyCode == Keys.L)
{
yourButton.PerformClick();
e.Handled = true;
}
}
EDIT:
I realized that the OP want to the keypress Event from his statement "but I don't think this would work if the window isn't active"
You probably must check this
How to set a Windows hook in Visual C# .NET
If you precede any character in the button text with &, and keep UseMnemonic to true,. the alt+character will serve as shortcut key.
For example, in your case change the text of the buttons to button&1 and button&2 respectively. Keep UserMnemonic = true. Now if you press alt+1 then button1 will be pressed and if you press alt+2, button2 will be pressed.
Also 1 and 2 respectively will be underlined.
Hope that helps.
In winform application, I am using a key down event to proceed to next field. It works properly but i want to handle an event of text box here as well like key press. If key down event on the form is available then key press event is not fired.
How can i resolve it.
Any suggestions?
Every KeyDown event receive a KeyEventArgs parameter.
Inside the KeyEventArgs parameter there is a property named SuppressKeyPress.
According to MSDN setting this property to true avoid the KeyPress event
If you set this property to false, the current control with focus will receive the keypress.
private void formMain_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
// Do your processing
....
e.Handled = true;
e.SuppressKeyPress = false;
}