I am trying to make a WinForm ListBox in which you can loop trough using the arrow keys. I also have two buttons on which you can click to go up and down the list. The buttons do produce the desired effect. The problem is that the ListBox's keyDown event is never triggered
public MainForm()
{
InitializeComponent();
if (this.clipboardHistoryList.Items.Count > 0)
this.clipboardHistoryList.SetSelected(0, true);
clipboardHistoryList.Select();
}
private void goUpButton_Click(object sender, EventArgs e)
{
goUpList();
}
private void goDownButton_Click(object sender, EventArgs e)
{
goDownList();
}
private void goDownList()
{
if (clipboardHistoryList.SelectedIndex == clipboardHistoryList.Items.Count - 1)
{
clipboardHistoryList.SetSelected(0, true);
}
else
{
clipboardHistoryList.SetSelected(clipboardHistoryList.SelectedIndex + 1, true);
}
}
private void goUpList()
{
if (clipboardHistoryList.SelectedIndex == 0)
{
clipboardHistoryList.SetSelected(clipboardHistoryList.Items.Count - 1, true);
}
else
{
int l_currentlySelected = clipboardHistoryList.SelectedIndex;
clipboardHistoryList.SetSelected(l_currentlySelected - 1, true);
}
}
private void clipboardHistoryList_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Up) //Brekpoint is never reached
{
goUpList();
}
else if (e.KeyCode == Keys.Down)
{
goDownList();
}
}
I have put the MainForm's keypreview proprety to true.
The arrow keys do work by default on a listbox but they won't let you go from last to first element if you press the down arrow on the last element --hopes this makes sense.
EDIT
I have seen on Microsoft's documentation that I need to override the ProcessDialogKey method but I am not exactly sure of what I need to do.
Perform special input or navigation handling on a control. For example, you want the use of arrow keys in your list control to change the selected item. Override ProcessDialogKey
Is there already a built-in way to enable this behaviour?
What did I miss?
Thanks!
From looking at the code in your Designer.cs file, it doesn't look like you've actually got your clipboardHistoryList control wired into your clipboardHistoryList_KeyDown event handler. You can do that through the "Events" subtab of the Properties window in your visual studio form designer (look for the little lightning bolt icon) and wire up the event through the designer that way, or alternatively you can do it in code:
public MainForm()
{
InitializeComponent();
if (this.clipboardHistoryList.Items.Count > 0)
this.clipboardHistoryList.SetSelected(0, true);
clipboardHistoryList.Select();
clipboardHistoryList.KeyDown += clipboardHistoryList_KeyDown;
}
Related
I am making a game where I need a constant keyboard listener (to navigate through the game). I tried getting the keyboard focus to one place and let it stay there using a seperate thread in a while true loop. This seems to crash my program.
Question:
Is there a method to get my keyboard focused on one element so I can grab my key input from there?
What can I use?:
something that works without throwing exceptions
something I can use in combination with other text input
something that doesn't take hours to compile
something that is easy to build another program (im not super good at c#)
What have I tried?
public MainWindow()
{
InitializeComponent();
Thread keyboardfocus = new Thread(GetFocus);
keyboardfocus.Start();
}
private void GetFocus()
{
while (true)
{
Keyboard.Focus(KeyboardButton);
}
}
private void KeyboardButton_OnKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Z)
{
map.PosUp -= 1;
MainCanvas.Background = Brushes.Aqua;
}
else if (e.Key == Key.S)
{
map.PosUp += 1;
MainCanvas.Background = Brushes.Black;
}
}
Thanks
Add event handler for Window.Loaded and set there a focus to the desired control:
private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
Keyboard.Focus(KeyboardButton);
}
Add event handler for the UIElement.LostKeyboardFocus in your case KeyboardButton and just set the keybord focus again to the KeyboardButton:
private void KeyboardButton_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
Keyboard.Focus(KeyboardButton);
}
I have a situation where I'm provided with a WinForms TextBox instance which I want to attach autocomplete functionality to.
I've got the autocomplete (string matching + dropdown) all figured out and it works reliable so far.
What is the ability to navigate the dropdown with the keyboard (as is the norm with this sort of UI).
The natural solution would be to handle KeyDown (or somesuch) event for the textbox and moving the selection in the dropdown accordingly.
However, it happens that to do this, you need to override the IsInputKey() event to allow capture of arrow key events. The alternative is to override ProcessCmdKey() and handle the event there. The problem with these two is that I cannot override anything since I can't replace the textbox instance.
Edit: Let's assume I have the code below:
void _textBox_KeyDown(object sender, KeyEventArgs e)
{
if (_dropdown.Visible)
{
// TODO The stuff below fails because we need to either handle ProcessCmdKey or override IsInputKey
switch (e.KeyCode)
{
case Keys.Tab:
{
// click selected item
_dropdown.Items[GetSelectedItemIndex()].PerformClick();
break;
}
case Keys.Down:
{
// select next (or first) item
int i = GetSelectedItemIndex() + 1;
if (i >= _dropdown.Items.Count) i = 0;
_dropdown.Items[i].Select();
break;
}
case Keys.Up:
{
// select previous (or last) item
int i = GetSelectedItemIndex() - 1;
if (i < 0) i = _dropdown.Items.Count - 1;
_dropdown.Items[i].Select();
break;
}
}
}
}
Them problem with the code above is that it is never called. The event is never triggered for arrow keys. More info: Up, Down, Left and Right arrow keys do not trigger KeyDown event
I hope i haven't missunderstood you, but is this a solution:
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Down)
{
// Place logic for textbox here
}
}
I'd use a KeyDown event on the form and then compare the keycode with the Keys.Down keycode
Not working
see here: Up, Down, Left and Right arrow keys do not trigger KeyDown event
I may not be understanding your question entirely, but wouldn't an approach like this work?
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
comboBox1.Text = //results of your matching algorithm.
}
private void textBox1_Validated(object sender, EventArgs e)
{
textBox1.Text = (string) comboBox1.Text;
}
I have a program containing multiple C# Forms TextBoxes. I've set up Hotkeys for the entire form activating certain functions. My problem is that my Hotkeys have been set onto the Form KeyDown event and they activate if I write something on a TextBox.
Example: One Hotkey might be I. Everytime I write the letter onto a textbox the Hotkey activates.
Alterior solutions and problems: I've thought about putting a Key in front of the Hotkey like CTRL+Hotkey, but these also present problems as CTRL+C is Windows Copy command etc. SHIFT is an UpperKey button.
Question: Can I prevent Hotkeys from activating when I am writing onto a TextBox without having to go through all of them in the form?
EDIT: Some code as requested. The button codes come from a stored XML file or the Hotkeys Form+Class (separate) where I've set up a window for them.
public Hotkeys hotkeysForm = new Hotkeys();
void Form1_KeyDown(object sender, KeyEventArgs e)
{
toggleInformation = hotkeysForm.toggleInformation;
if (e.Control && e.KeyCode == toggleInformation)
{
showInfo(true);
}
else if (e.KeyCode == toggleInformation)
{
if (!isInfoActive)
showInfo();
else
hideInfo();
}
}
You can disable hotkeys while texbox is an active control. Add the Enter and Leave events for all textboxes:
private void textBox_Enter(object sender, EventArgs e)
{
KeyPreview = false;
}
private void textBox_Leave(object sender, EventArgs e)
{
KeyPreview = true;
}
You should try this hack, if it could solve your problem,
Create a Extented TextBox and use it in your code. you can handle whether to write the pressed key in textbox or not in hotkeyPressed check.
public class ETextBox : System.Windows.Forms.TextBox
{
protected override void OnKeyDown(System.Windows.Forms.KeyEventArgs e)
{
if (hotKeyPressed) // this is the condition when you don't want to write in text.
{
//Do whatever you want to do in this case.
}
else
{
base.OnKeyDown(e);
}
}
}
How to catch keyboard events of the WinForm main form, where other controls are.
So I want to catch one event Ctrl + S and doesn't matter where focus is.
But without Pinvoke (hooks and such ...)
Only .NET managed internal power.
Try this code. Use the interface IMessageFilter you can filter any ctrl+key.
public partial class Form1 :
Form,
IMessageFilter
{
public Form1()
{
InitializeComponent();
Application.AddMessageFilter(this);
this.FormClosed += new FormClosedEventHandler(this.Form1_FormClosed);
}
private void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
Application.RemoveMessageFilter(this);
}
public bool PreFilterMessage(ref Message m)
{
//here you can specify which key you need to filter
if (m.Msg == 0x0100 && (Keys)m.WParam.ToInt32() == Keys.S &&
ModifierKeys == Keys.Control)
{
return true;
}
else
{
return false;
}
}
}
I tested this and worked for me.
the Form Class (System.Windows.Forms) has OnKeyDown, OnKeyPress, and OnKeyUp event methods that you can use to detect Ctrl + S
use the KeyEventArgs in those methods to determine which keys were pressed
EDIT
be sure to enable Form.KeyPreview = true; so the form will capture the events regardless of focus.
Handle the KeyDown on the form and all its controls.
private void OnFormLoad(object sender, EventArgs e)
{
this.KeyDown += OnKeyDown;
foreach (Control control in this.Controls)
{
control.KeyDown += OnKeyDown;
}
}
private void OnKeyDown(object sender, KeyEventArgs e)
{
if (e.Control)
{
if (e.KeyValue == (int)Keys.S)
{
Console.WriteLine("ctrl + s");
}
}
}
You may add a MenuStrip and then create a menu strip item named save and give it a short cut Ctrl + S. Add a event handler for that. This will fire even if the focus is on other control on the form. If you don't like to see the MenuStrip; you can set visible = false too. I must admit this is ugly.
I am using a windows form and within the form i have a user control with two labels, one that has a message ENTER AMOUNT and the other where I am putting the values typed by the user (like when you go to an ATM) it starts showing the number .. it works fine if i dont have any other controls on the user control.. but the moment i add a button it does not work, it wont start showing the numbers as I use my numeric key pad.. but if i remove whatever button i added it works again... Here is my user control code.
public partial class OperationAmount : UserControl
{
public OperationAmount()
{
InitializeComponent();
}
private int _inputNumber = 0;
private void OperationAmount_Load(object sender, EventArgs e)
{
}
private void Form_KeyAmountPressed(object sender, KeyPressEventArgs e)
{
if (!Char.IsNumber(e.KeyChar))
{
return;
}
else if (lblOperationAmount.Text.Length > 9)
{
return;
}
else
{
_inputNumber = 10 * _inputNumber + Int32.Parse(e.KeyChar.ToString());
ReformatOutput();
}
}
private void ReformatOutput()
{
lblOperationAmount.Text = String.Format("{0:0.00}", (double)_inputNumber / 100.0);
}
}
Probably the new control steals the keypresses from your Form_KeyAmountPressed method because now it has the focus and receive the event KeyPress.
A simple workaround would be to add the method Form_KeyAmountPressed also at the KeyPress event of the button. Try also to set the TabStop property of the button to false. (not sure if this has any effect when the button is the only control that can get focus on your user control).