I am creating a small game, the game is printed onto a panel on a windows form. Now i want to capture the keydown event to see if its the arrow keys that has been pressed, the problem however is that i can't seem to capture it.
Let me explain, on the form i have 4 buttons and various other controls and if the user for instance press one of the buttons (to trigger a game event) then the button has focus and i can't capture the movements with the arrow keys.
I tried something like
private void KeyDown(KeyEventArgs e)
{
if (e.KeyCode == Keys.Left)
{
game.MovePlayer(DonutWarsLibrary.GameObjects.Direction.E);
game.DrawObjects(panel1.CreateGraphics());
}
else if (e.KeyCode == Keys.Right)
{
game.MovePlayer(DonutWarsLibrary.GameObjects.Direction.W);
game.DrawObjects(panel1.CreateGraphics());
}
else if (e.KeyCode == Keys.Up)
{
game.MovePlayer(DonutWarsLibrary.GameObjects.Direction.N);
game.DrawObjects(panel1.CreateGraphics());
}
else if (e.KeyCode == Keys.Down)
{
game.MovePlayer(DonutWarsLibrary.GameObjects.Direction.S);
game.DrawObjects(panel1.CreateGraphics());
}
}
and then when the form key down event was pressed, i used this
private void MainForm_KeyDown(object sender, KeyEventArgs e)
{
KeyDown(e);
}
I also added keydown for the buttons and the various other controls on the windows form, but i am not getting any response back. I have setup a breakpoint inside the function to see if it's being called, but that breakpoint never triggers?
Any ideas?
The most optimal was to have a general KeyDown event that triggers (regardless of what control that currently has focus) and then calls the KeyDown method.
Have you set the KeyPreview property of the form to true? That will cause the form to get a "first look" at key events.
Update: getting this to work properly when a Button has focus seems to be a bit tricky. The Button control intercepts the arrow key presses and moves focus to the next or previous control in the tab order in a manner so that the KeyDown, KeyUp and KeyPress events are not raised. However, the PreviewKeyDown event is raised, so that can be used:
private void Form_KeyDown(object sender, KeyEventArgs e)
{
e.Handled = ProcessKeyDown(e.KeyCode);
}
// event handler for the PreViewKeyDown event for the buttons
private void ArrowButton_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
ProcessKeyDown(e.KeyCode);
}
private bool ProcessKeyDown(Keys keyCode)
{
switch (keyCode)
{
case Keys.Up:
{
// act on up arrow
return true;
}
case Keys.Down:
{
// act on down arrow
return true;
}
case Keys.Left:
{
// act on left arrow
return true;
}
case Keys.Right:
{
// act on right arrow
return true;
}
}
return false;
}
Still, the focus moves around in a rather ugly manner...
I believe the easiest way of solving this problem is through overriding the ProcessCmdKey() method of the form. That way, your key handling logic gets executed no matter what control has focus at the time of keypress. Beside that, you even get to choose whether the focused control gets the key after you processed it (return false) or not (return true).
Your little game example could be rewritten like this:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (keyData == Keys.Left)
{
MoveLeft(); DrawGame(); DoWhatever();
return true; //for the active control to see the keypress, return false
}
else if (keyData == Keys.Right)
{
MoveRight(); DrawGame(); DoWhatever();
return true; //for the active control to see the keypress, return false
}
else if (keyData == Keys.Up)
{
MoveUp(); DrawGame(); DoWhatever();
return true; //for the active control to see the keypress, return false
}
else if (keyData == Keys.Down)
{
MoveDown(); DrawGame(); DoWhatever();
return true; //for the active control to see the keypress, return false
}
else
return base.ProcessCmdKey(ref msg, keyData);
}
Override IsInputKey behaviour
You must override the IsInputKey behavior to inform that you want the Right Arrow key to be treated as an InputKey and not as a special behavior key.
For that you must override the method for each of your controls.
I would advise you to create your won Buttons, let's say MyButton
The class below creates a custom Button that overrides the IsInputKey method so that the right arrow key is not treated as a special key. From there you can easily make it for the other arrow keys or anything else.
public partial class MyButton : Button
{
protected override bool IsInputKey(Keys keyData)
{
if (keyData == Keys.Right)
{
return true;
}
else
{
return base.IsInputKey(keyData);
}
}
}
Afterwards, you can treat your keyDown event event in each different Button or in the form itself:
In the Buttons' KeyDown Method try to set these properties:
private void myButton1_KeyDown(object sender, KeyEventArgs e)
{
e.Handled = true;
//DoSomething();
}
-- OR --
handle the common behaviour in the form: (do not set e.Handled = true; in the buttons)
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
//DoSomething();
}
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
KeyPreview = true;
KeyDown += new KeyEventHandler(Form1_KeyDown);
}
void Form1_KeyDown(object sender, KeyEventArgs e)
{
System.Diagnostics.Debug.Write(e.KeyCode);
}
}
Related
I am trying to disable tab key from datagridview, also to create my own event on it. Also if it is possible to disable up,down,right,left and enter key.
OnLoad Event
this.dataGridView1.EditMode = DataGridViewEditMode.EditOnEnter;
On KeyDownEvent
private void gridInvoice_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Tab)
{
//SelectNextControl(dataGridView1, true, true, true, true);
// or Parent.SelectNextControl() if the grid is an only child, etc.
e.Handled = true;
}
}
With code above tab key it works. I moves to next cell. How can i prevent this?
You have to use PreviewKeyDown event instead of KeyDown.
According to Microsoft Control.PreviewKeyDown Event Description
Some key presses, such as the TAB, RETURN, ESC, and arrow keys, are typically ignored by some controls because they are not considered input key presses.
You need to insert the code below in PreviewKeyDown event if you want to use KeyDown event when Tab is pressed.
if (e.KeyCode == Keys.Tab) { e.IsInputKey = true; }
When in editmode thanks to Jimi
I'm sorry I thought the problem too simple. How about this. You can override ProcessCmdKey to ignore Tab when you in editmode of your DGV. Is it too brute?
I think this is simple than make a new edit control but not elegance too.
protected override bool ProcessCmdKey(ref System.Windows.Forms.Message msg, System.Windows.Forms.Keys keyData)
{
if (keyData == Keys.Tab && dataGridView1.EditingControl != null) { return true; }
else return base.ProcessCmdKey(ref msg, keyData);
}
from Similar problem
I have a Windows Form Application. I want some functions to work with the space key. But when I press the space key, the function I want is not working and it goes to the next form. (I did KeyPreview = true)
private void Form7_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Space)
{
IEyeTracker eyeTracker = EyeTrackingOperations.FindAllEyeTrackers().FirstOrDefault();
GazeDataStop(eyeTracker);
}
}
Because:
1- If you have buttons, ... keydown won't work as form won't have focus anymore
2-you must handle the keydown so that it is not passed to ohter controls
Solution for 1:
set KeyPreview property of your form to true
Solution for 2:
set e.Handled = true:
private void Form7_KeyDown(object sender, KeyEventArgs e)
{
e.Handled = true;
if (e.KeyCode == Keys.Space)
{
IEyeTracker eyeTracker = EyeTrackingOperations.FindAllEyeTrackers().FirstOrDefault();
GazeDataStop(eyeTracker);
}
}
I currently have the following event handler which catches the Ctrl+Enter key combo in my Form code:
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter && e.Control)
{
// Stuff
}
}
I also have two non-ReadOnly TextBoxes in the form, one of which is multiline, while the other one isn't. Whenever I hit Ctrl+Enter, the event does get handled, but it also registers as an Enter keypress when the focus is in either TextBox. What I want to do is register the key combo without the Enter keypress modifying the text in either box. Is there any way I could go about doing this?
Your best choice is use ProcessCmdKey: Just add this to your Form add it will work:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (keyData == (Keys.Control | Keys.Enter))
{
// Stuff
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
You should use the PreviewKeyDown event instead and set the IsInputKey property accordingly:
private void Form1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (e.KeyCode == Keys.Enter && e.Control)
{
// Stuff
e.IsInputKey = false;
}
}
UPDATE: From the name of your handler, I guess you added it to the Form's KeyPress/KeyDown/PreviewKeyDown event. Instead you should register the method I showed above with each TextBox's PreviewKeyDown event.
To not destroy what already works for you, you may leave your code as it is and just add a handler to the TextBox's PreviewKeyDown event where you set IsInputKey to false for the specified keys, but don't do your // Stuff.
This is not a duplicate. Many similar threads discuss capturing a combination involving a modifier key.
I need to get something triggered when a shortcut key (a combination of Insert+Tab) is pressed from a control, say Button.
Catch:
This involves no modifier key like Alt or Shift for which .NET has built in checking.
This has Tab key which is not caught so easily.
What I tried and came close:
1) KeyDown Event but doesnt capture Tabs..
[DllImport("user32.dll")]
public static extern int GetKeyboardState(byte[] keystate);
static void form_KeyDown(object sender, KeyEventArgs e)
{
if (!(((Form)sender).ActiveControl is Button))
return;
byte[] keys = new byte[255];
GetKeyboardState(keys);
if (keys[(int)Keys.Insert] == 129 && keys[(int)Keys.Tab] == 129)
{
// doesn't work
}
if (keys[(int)Keys.Insert] == 129 && keys[(int)Keys.J] == 129)
{
// works, since here this doesnt involve Tab
}
}
This works with regular combinations, doesnt fire along with Tab.
2) KeyPreview Event which captures Tab key, but I do not know how to get a combination of keys pressed
static void form_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (!(((Form)sender).ActiveControl is Button))
return;
if (e.KeyCode == Keys.Tab)
//works
if (e.KeyCode == Keys.Insert && e.KeyCode == Keys.Tab)
//doesn't hit.
}
Requirement:
1) I am not registering the event from Form class. Instead I have a utility class which creates all required events (along with other shortcuts). I just pass the instance of form to a static function. So I am quite unsure how I should utilize the various key overriding calls. Here is how I do it:
public frmLogin()
{
InitializeComponent();
Utility.SetFormEvents(this);
}
static void SetFormEvents(Form f){
//foreach control...........
}
But I can give up on this..
Thanks..
Tab is considered a command key, you don't actually get notified of it being pressed directly. You could PInvoke the GetKeyState method, but I think it's just easier to recognize that tab is a command key (and override ProcessCmdKey) and keep track of whether the Insert key is up or down. For example:
static bool insertPressed;
static bool tabPressed;
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if(keyData == Keys.Tab)
{
tabPressed = true;
CheckForTabAndInsert();
}
return base.ProcessCmdKey(ref msg, keyData);
}
static void form_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Insert)
{
insertPressed = true;
CheckForTabAndInsert();
insertPressed = false;
}
}
static void form_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Insert) insertPressed = false;
}
The drawback is that you only really get a KeyPress for tab with ProcessCmdKey, so you can only really support Insert+Tab (not Tab+Insert). This is because Tab is used to switch context from one control to another. Depending on your situation (i.e. in the context of a text box), you could make use of the AcceptTab property to possibly just use KeyUp and KeyDown... But, from what you posted, that doesn't appear to be the case.
I have a form with a button in. I want to capture the Form.KeyDown event.
private void buttonStart_Click(object sender, EventArgs e)
{
if (!this.gameRunning)
{
this.buttonStrat.Text = "Pause";
this.timer1.Enabled = true;
}
else
{
this.buttonStart.Text = "Continue";
this.timer1.Enabled = false;
}
this.gameRunning = !this.gameRunning;
}
However, I was disabling buttonStart without supporting PAUSE and it was working nice. Since I have added the PAUSE advantage, the Form.KeyDown event doesn't raise and buttonStart is Focused. Whenever I disable buttonStart, it fires.
NOTES:
I have set Form.KeyPreview to true, stills doesn't raise
I have set Form.AcceptButton to null, stills doesn't raise
I have made buttonStart subscriped to Form.KeyDown, stills doesn't.
I hope this will helps you ..
Override IsInputKey behaviour
You must override the IsInputKey behavior to inform that you want the Right Arrow key to be treated as an InputKey and not as a special behavior key.
For that you must override the method for each of your controls.
I would advise you to create your won Buttons, let's say MyButton
The class below creates a custom Button that overrides the IsInputKey method so that the right arrow key is not treated as a special key. From there you can easily make it for the other arrow keys or anything else.
public partial class MyButton : Button
{
protected override bool IsInputKey(Keys keyData)
{
if (keyData == Keys.Right)
{
return true;
}
else
{
return base.IsInputKey(keyData);
}
}
}
Afterwards, you can treat your keyDown event event in each different Button or in the form itself:
In the Buttons' KeyDown Method try to set these properties:
private void myButton1_KeyDown(object sender, KeyEventArgs e)
{
e.Handled = true;
//DoSomething();
}
-- OR --
handle the common behaviour in the form: (do not set e.Handled = true; in the buttons)
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
//DoSomething();
}