Iam facing such problem, which I find hard to overcome. In WinForms I got a TabControl with n TabPages. I want to extend the Ctrl+Tab / Ctrl+Shift+Tab switching. so I wrote some code which works fine as long as the focus is on TabControl or on the Form. When application focus is INSIDE of TabPage (for example on a button which is placed inside of TabPage), while pressing Ctrl+Tab, my code is ignored and TabControl skips to TabPage on his own (avoiding my code).
Anyone idea ?
You need to derive from TabControl and override ProcessCmdKey, virtual method in order to override the Ctrl-Tab behavior.
Example:
public class ExtendedTabControl: TabControl
{
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (keyData == (Keys.Control | Keys.Tab))
{
// Write custom logic here
return true;
}
if (keyData == (Keys.Control | Keys.Shift | Keys.Tab))
{
// Write custom logic here, for backward switching
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
}
TabControl has fairly unusual processing to handle the Tab key. It overrides the ProcessKeyPreview() method to detect Ctrl/Shift/Tab, then implements the tab selection in its OnKeyDown() method. It does this so it can detect the keystroke both when it has the focus itself as well as any child control. And to avoid stepping on custom Tab key processing by one of its child controls. You can make it work by overriding ProcessCmdKey() but then you'll break child controls that want to respond to tabs.
Best thing to do is to override its OnKeyDown() method. Add a new class to your project and paste the code shown below. Compile. Drop the new tab control from the top of the toolbox onto your form.
using System;
using System.Windows.Forms;
class MyTabControl : TabControl {
protected override void OnKeyDown(KeyEventArgs e) {
if (e.KeyCode == Keys.Tab && (e.KeyData & Keys.Control) != Keys.None) {
bool forward = (e.KeyData & Keys.Shift) == Keys.None;
// Do your stuff
//...
}
else base.OnKeyDown(e);
}
}
Beware that you also ought to consider Ctrl+PageUp and Ctrl+PageDown.
Related
I'm looking for a best way to implement common Windows keyboard shortcuts (for example Ctrl+F, Ctrl+N) in my Windows Forms application in C#.
The application has a main form which hosts many child forms (one at a time). When a user hits Ctrl+F, I'd like to show a custom search form. The search form would depend on the current open child form in the application.
I was thinking of using something like this in the ChildForm_KeyDown event:
if (e.KeyCode == Keys.F && Control.ModifierKeys == Keys.Control)
// Show search form
But this doesn't work. The event doesn't even fire when you press a key. What is the solution?
You probably forgot to set the form's KeyPreview property to True. Overriding the ProcessCmdKey() method is the generic solution:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
if (keyData == (Keys.Control | Keys.F)) {
MessageBox.Show("What the Ctrl+F?");
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
On your Main form
Set KeyPreview to True
Add KeyDown event handler with the following code
private void MainForm_KeyDown(object sender, KeyEventArgs e)
{
if (e.Control && e.KeyCode == Keys.N)
{
SearchForm searchForm = new SearchForm();
searchForm.Show();
}
}
The best way is to use menu mnemonics, i.e. to have menu entries in your main form that get assigned the keyboard shortcut you want. Then everything else is handled internally and all you have to do is to implement the appropriate action that gets executed in the Click event handler of that menu entry.
You can even try this example:
public class MDIParent : System.Windows.Forms.Form
{
public bool NextTab()
{
// some code
}
public bool PreviousTab()
{
// some code
}
protected override bool ProcessCmdKey(ref Message message, Keys keys)
{
switch (keys)
{
case Keys.Control | Keys.Tab:
{
NextTab();
return true;
}
case Keys.Control | Keys.Shift | Keys.Tab:
{
PreviousTab();
return true;
}
}
return base.ProcessCmdKey(ref message, keys);
}
}
public class mySecondForm : System.Windows.Forms.Form
{
// some code...
}
If you have a menu then changing ShortcutKeys property of the ToolStripMenuItem should do the trick.
If not, you could create one and set its visible property to false.
From the main Form, you have to:
Be sure you set KeyPreview to true( TRUE by default)
Add MainForm_KeyDown(..) - by which you can set here any shortcuts you want.
Additionally,I have found this on google and I wanted to share this to those who are still searching for answers. (for global)
I think you have to be using user32.dll
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == 0x0312)
{
/* Note that the three lines below are not needed if you only want to register one hotkey.
* The below lines are useful in case you want to register multiple keys, which you can use a switch with the id as argument, or if you want to know which key/modifier was pressed for some particular reason. */
Keys key = (Keys)(((int)m.LParam >> 16) & 0xFFFF); // The key of the hotkey that was pressed.
KeyModifier modifier = (KeyModifier)((int)m.LParam & 0xFFFF); // The modifier of the hotkey that was pressed.
int id = m.WParam.ToInt32(); // The id of the hotkey that was pressed.
MessageBox.Show("Hotkey has been pressed!");
// do something
}
}
Further read this http://www.fluxbytes.com/csharp/how-to-register-a-global-hotkey-for-your-application-in-c/
Hans's answer could be made a little easier for someone new to this, so here is my version.
You do not need to fool with KeyPreview, leave it set to false. To use the code below, just paste it below your form1_load and run with F5 to see it work:
protected override void OnKeyPress(KeyPressEventArgs ex)
{
string xo = ex.KeyChar.ToString();
if (xo == "q") //You pressed "q" key on the keyboard
{
Form2 f2 = new Form2();
f2.Show();
}
}
In WinForm, we can always get the Control Key status by:
bool IsCtrlPressed = (Control.ModifierKeys & Keys.Control) != 0;
The VB.NET version of Hans' answer.
(There's a ProcessCmdKey function template in Visual Studio.)
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
If (keyData = (Keys.Control Or Keys.F)) Then
' call your sub here, like
SearchDialog()
Return True
End If
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
End Class
I have just found out that we can't use the KeyDown event directly with a PictureBox. So I have to change my strategy.
I decided to add the Keydown event to the actual form:
private void FullColourPaletteForm_KeyDown(object sender, KeyEventArgs e)
{
switch (e.KeyCode)
{
case Keys.Left:
{
MessageBox.Show("Left");
e.Handled = true;
return;
}
}
}
Doesn't get executed. I see no message box when I press the left allow. Instead (and rightly so) it just moves the cusor from control to control.
I was hoping to be able to mimic some kind of cursor support for the block of colour by intercepting the arrow keys inside the picture box.
I am not sure of the best way forward. I don't want to break the standard dialogue functionality of moving between controls, but I want to now include suipport for detectign keys so I can add my code to move my block of colour.
Can it be done? Not sure why my event is not getting triggered in the form anyway.
I saw this question. So I tried setting my form KeyPreview property. No joy. I also looked at ProcessCmdKey but it doesn't seem right for the issue in hand.
Update:
If I try to follow the idea in the comments and create a SelectablePictureBox control, it looks like this:
I have two issues. 1. I still can't seem to work out how to handle the keydown event on my pictureBox object itself. I am reluctant to manually add any handlers to the designer file incase my changes get lost.
Also, when doing general control nagivation on the form with cursor keys it does not seem to know about this control.
If you want to handle arrow keys at form level, you can override the form's ProcessCmdKey function this way:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (keyData == Keys.Left)
{
MessageBox.Show("Left");
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
But in general it's better to create a custom paint selectable control like this rather than putting such logic at form level. Your control should contain such logic.
Note
OP: I have just found out that we can't use the KeyDown event directly
with a PictureBox
As mentioned by Hans in comments, the PictureBox control is not selectable and can not be focused by default and you can not handle keyboard events for the control.
But you can force it to be selectable and support keyboard events this way:
using System;
using System.Reflection;
using System.Windows.Forms;
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.pictureBox1.SetStyle(ControlStyles.Selectable, true);
this.pictureBox1.SetStyle(ControlStyles.UserMouse, true);
this.pictureBox1.PreviewKeyDown +=
new PreviewKeyDownEventHandler(pictureBox1_PreviewKeyDown);
}
void pictureBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (e.KeyData == Keys.Left)
MessageBox.Show("Left");
}
}
public static class Extensions
{
public static void SetStyle(this Control control, ControlStyles flags, bool value)
{
Type type = control.GetType();
BindingFlags bindingFlags = BindingFlags.NonPublic | BindingFlags.Instance;
MethodInfo method = type.GetMethod("SetStyle", bindingFlags);
if (method != null)
{
object[] param = { flags, value };
method.Invoke(control, param);
}
}
}
At least knowing this approach as a hack you can reuse the extension method to enable or disable some styles on controls in future.
I'm facing a little problem I can't seem to solve.
The problem is in an WinForm I have several containers (TabControls, Panels, ...).
The Tab-order within the controls work fine (of course). But now a customer asked to change the taborder to jump from a textbox in the first container (current tabindex 0,0,1) to a control in another container (current tabindex 0,1,0,1).
My first approach was setting the tabindex of the second to 0,0,1,1 but with no effect. The tab jumps from 0,0,1 to 0,0,2.
I tried a couple of other combinations too but with no result.
Can anybody provide me with hints how I might solve this problem?
PS: the 0,0,0 stands for the containers that contain the control just in case this is not clear
You could work with the Leave event of that Control, and manually set focus in the code behind to do this.
private void textBox1_Leave(object sender, System.EventArgs e)
{
textBox2.Focus();
}
If you want to use the TAB key, it's better to not use the Leave event
It will create some bad redirections if you change with your mouse for example.
Better override ProcessCmdKey
Here is a good solution :
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
bool baseResult = base.ProcessCmdKey(ref msg, keyData);
//if key is tab and TextBox1 is focused then jump to TextBox2
if (keyData == Keys.Tab && TextBox1.Focused)
{
TextBox2.Focus();
return true;
}
else if (keyData == Keys.Tab && TexBox2.Focused)
{
TextBox3.Focus();
return true;
}
return baseResult;
}
Hope it helped.
I have a form with a single text box on it. No other controls. Whenever I type the 'Enter' key or the 'Esc' key, the form functions as I desire; but I hear that horrible Windows error sound. The code looks similar to the following...
public class EntryForm: Form
{
public EntryForm()
{
}
private void EntryTextBox_KeyUp(object sender, KeyEventArgs e)
{
if(e.KeyCode == Keys.Enter)
{
// do some stuff
Hide(); // I've also used DialogResult = DialogResult.OK here
e.Handled = true;
}
else if(e.KeyCode == Keys.Escape)
{
Hide(); // I've also used DialogResult = DialogResult.Cancel here
e.Handled = true;
}
}
}
I can 'hack' it and make the noise stop by adding the following code to the form's constructor.
AcceptButton = new Button();
CancelButton = new Button();
As I stated this causes the sound to not play, but I think this is bad form; especially since I don't need a button on the form.
Anyone know why this is the behavior and if there is a cleaner way to stop the error sound from playing?
In the KeyDown event, set e.Handled = true and e.SuppressKeyPress = true.
There's a more "correct" fix, one that works regardless of how many controls you have and follows the Windows Forms design model. Paste this code into your form:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
if (keyData == Keys.Escape || keyData == Keys.Enter) {
this.Hide();
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
This is too long a reply to Nobugz answer to fit in a comment. If you use Nobugz code as is :
the Form is going to be hidden no matter which control on the form is active and has keyboard input focus, and that is independent of whether the Form has the 'KeyPreview property set to 'true or 'false.
Here's what you need to do to make only a specific control (in this case a TextBox named 'textBox1) be hidden in the ProcessCmdKeys over-ride :
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (msg.HWnd == textBox1.Handle)
{
if (keyData == Keys.Escape || keyData == Keys.Enter)
{
textBox1.Hide();
return true;
}
}
return base.ProcessCmdKey(ref msg, keyData);
}
Of course if you wanted to handle the case of multiple controls needing to be hidden, you could implement a 'switch statement or whatever to test the msg.HWnd against : note I make the assumption here that all controls that could have keyboard input will have a valid HWnd.
Some memory (vague) of a situation in which I used this technique, and a text input control somehow still had keyboard input focus ... when I did not intend for it to ... makes me want to add an additional test like this :
&& this.ActiveControl == textBox1
But, take that with a "grain of salt" since I can't be certain it is necessary.
I'm looking for a best way to implement common Windows keyboard shortcuts (for example Ctrl+F, Ctrl+N) in my Windows Forms application in C#.
The application has a main form which hosts many child forms (one at a time). When a user hits Ctrl+F, I'd like to show a custom search form. The search form would depend on the current open child form in the application.
I was thinking of using something like this in the ChildForm_KeyDown event:
if (e.KeyCode == Keys.F && Control.ModifierKeys == Keys.Control)
// Show search form
But this doesn't work. The event doesn't even fire when you press a key. What is the solution?
You probably forgot to set the form's KeyPreview property to True. Overriding the ProcessCmdKey() method is the generic solution:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
if (keyData == (Keys.Control | Keys.F)) {
MessageBox.Show("What the Ctrl+F?");
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
On your Main form
Set KeyPreview to True
Add KeyDown event handler with the following code
private void MainForm_KeyDown(object sender, KeyEventArgs e)
{
if (e.Control && e.KeyCode == Keys.N)
{
SearchForm searchForm = new SearchForm();
searchForm.Show();
}
}
The best way is to use menu mnemonics, i.e. to have menu entries in your main form that get assigned the keyboard shortcut you want. Then everything else is handled internally and all you have to do is to implement the appropriate action that gets executed in the Click event handler of that menu entry.
You can even try this example:
public class MDIParent : System.Windows.Forms.Form
{
public bool NextTab()
{
// some code
}
public bool PreviousTab()
{
// some code
}
protected override bool ProcessCmdKey(ref Message message, Keys keys)
{
switch (keys)
{
case Keys.Control | Keys.Tab:
{
NextTab();
return true;
}
case Keys.Control | Keys.Shift | Keys.Tab:
{
PreviousTab();
return true;
}
}
return base.ProcessCmdKey(ref message, keys);
}
}
public class mySecondForm : System.Windows.Forms.Form
{
// some code...
}
If you have a menu then changing ShortcutKeys property of the ToolStripMenuItem should do the trick.
If not, you could create one and set its visible property to false.
From the main Form, you have to:
Be sure you set KeyPreview to true( TRUE by default)
Add MainForm_KeyDown(..) - by which you can set here any shortcuts you want.
Additionally,I have found this on google and I wanted to share this to those who are still searching for answers. (for global)
I think you have to be using user32.dll
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == 0x0312)
{
/* Note that the three lines below are not needed if you only want to register one hotkey.
* The below lines are useful in case you want to register multiple keys, which you can use a switch with the id as argument, or if you want to know which key/modifier was pressed for some particular reason. */
Keys key = (Keys)(((int)m.LParam >> 16) & 0xFFFF); // The key of the hotkey that was pressed.
KeyModifier modifier = (KeyModifier)((int)m.LParam & 0xFFFF); // The modifier of the hotkey that was pressed.
int id = m.WParam.ToInt32(); // The id of the hotkey that was pressed.
MessageBox.Show("Hotkey has been pressed!");
// do something
}
}
Further read this http://www.fluxbytes.com/csharp/how-to-register-a-global-hotkey-for-your-application-in-c/
Hans's answer could be made a little easier for someone new to this, so here is my version.
You do not need to fool with KeyPreview, leave it set to false. To use the code below, just paste it below your form1_load and run with F5 to see it work:
protected override void OnKeyPress(KeyPressEventArgs ex)
{
string xo = ex.KeyChar.ToString();
if (xo == "q") //You pressed "q" key on the keyboard
{
Form2 f2 = new Form2();
f2.Show();
}
}
In WinForm, we can always get the Control Key status by:
bool IsCtrlPressed = (Control.ModifierKeys & Keys.Control) != 0;
The VB.NET version of Hans' answer.
(There's a ProcessCmdKey function template in Visual Studio.)
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
If (keyData = (Keys.Control Or Keys.F)) Then
' call your sub here, like
SearchDialog()
Return True
End If
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
End Class