I know this has been asked hundred of times, but I haven't been able to find a solution that helps me. I'm using a barcode scanner and I want to be able to get the keys that are typed using just the keydown events. For some reason, I can't use both keydown and keypress events (my keypress events won't run).
I need to be able to get the characters, including hyphens, uppercase letters and dots and also need to detect the enter key.
These are my listeners:
form.KeyDown += new KeyEventHandler(Input_KeyDown);
form.KeyPress += new KeyPressEventHandler(Input_KeyPress);
And these are my methods:
private void TimedOut(object sender, EventArgs e)
{
_barcode = "";
}
private void Input_KeyDown(object sender, KeyEventArgs e)
{
_timer.Stop();
_timer.Start();
if (e.KeyData == Keys.Enter)
{
if (!_barcode.Equals(""))
{
this.BarcodeScanned(_barcode, new EventArgs());
}
}
else
{
}
}
private void Input_KeyPress(object sender, KeyPressEventArgs e)
{
_timer.Stop();
_timer.Start();
_barcode += e.KeyChar;
}
Your code above works...on a blank form. However there are several things that can interfere with the key events, especially when there are other controls on the page. Make sure that
The AcceptButton property isn't set on the form (this will trap the Enter key)
That there are no controls on the form with TabStop set to true (might not be viable but give it a go)
That the form has focus when you're typing (unlikely given the description but check anyway)
That focus is not otherwise on any control in the form when typing, e.g., a TextBox
That no other controls are trying to process the KeyPress or KeyDown events and that no other custom events are configured/set anywhere else in your code
One thing I notice is that you are registering the events like so;
form.KeyDown += new KeyEventHandler(Input_KeyDown);
This implies that you are instantiating this form from another place and trying to get it to send its key events to the calling code. Are you sure that the form instance is persisted/saved to a private class level variable or some such?
Related
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);
}
}
}
I have numeric buttons which when pressed display the number in different text boxes. Now my problem is that i want check which textbox has focus so that the number pressed will be entered in that textbox.
My Code:
private void btn_one_Click(object sender, EventArgs e)
{
if (txt_one.Focused==true)
{
txt_one.Text += btn_one.Text;
}
else if (txt_two.Focused==true)
{
txt_two.Text += btn_one.Text;
}
}
Now my problem is that the above code is not working what is wrong and what will be the solution? I even used something like this
private void btn_one_Click(object sender, EventArgs e)
{
if (txt_one.Focus()==true)
{
txt_one.Text += btn_one.Text;
}
else if (txt_two.Focus()=true)
{
txt_two.Text += btn_one.Text;
}
}
In both the above cases the text is entered in both the text boxes. Any solutions.
This problem is a little tricky (with my experience dealing with Enter, Focus, LostFocus, Leave events, all these things sometimes make your head ache a lot and you should avoid dealing with them if possible), at the time you click your Button, the current Focused control you can know is exactly the Button (ActiveControl is one short way to access it). So the solution is we have to record the track of focused TextBox, hold it in a reference and use it when needed. In fact if the control other than one of your TextBoxes is focused, we have to reset the variable lastFocused to null:
TextBox lastFocused;
//Enter event handler for all your TextBoxes
private void TextBoxes_Enter(object sender, EventArgs e){
lastFocused = sender as TextBox;
}
//Click event handler for your button
private void btn_one_Click(object sender, EventArgs e){
if(lastFocused != null) lastFocused.Text += btn_one.Text;
}
I am trying to control user input when he/she wants to edit a treeNode. I don't want him to be able to write numbers (or even better not write a number at given index of the text but thats a bonus)
What I did was make a boolean on the mainWindow that determines if the user is editing the treeNode or not like this:
void Tree_AfterLabelEdit(object sender, System.Windows.Forms.NodeLabelEditEventArgs e) {
isEditing = false;
}
void Tree_BeforeLabelEdit(object sender, System.Windows.Forms.NodeLabelEditEventArgs e) {
isEditing = true;
}
private void Tree_KeyDown(object sender, KeyEventArgs e) {
control input. (e.Handled = true when keyDown is a number.)
}
This is what I tried but the event keydown is only called when I am NOT editing a treenode. So it falls out of purpose. (I use keydown already to handle arrow key events but I want to do both.)
Tried with keypress aswell to no avail.
The TreeView does not have any mechanism to control the LabelEdit part. Even if you can handle the KeyDown part of the Label to prevent numbers, you would still have to inspect the contents on the AfterLabelEdit because the user can "paste" numbers into the field as well. It's best to just control it during the AfterLabelEdit event:
private void treeView1_AfterLabelEdit(object sender, NodeLabelEditEventArgs e)
{
foreach (char c in e.Label)
{
if (char.IsNumber(c))
e.CancelEdit = true;
}
}
I am attempting to move a PictureBox(picUser) up and down via the key press events. I am newer to C# and am able to do this via VB. As such I am confused as to what the problem is with the following code:
private void picUser_keyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.W)
{
picUser.Top -= 10;
}
}
There is no "error" with the code, the picturebox just doesn't move.
A PictureBox has no KeyDown event. It has a PreviewKeyDown instead and requires the PictureBox to have the focus.
I would suggest to use the KeyDown of the form that host the PictureBox instead and use the same exact code:
public Form1()
{
InitializeComponent();
this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Form1_KeyDown);
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.W)
{
picUser.Top -= 10;
}
}
It's probably not working because picUser does not have the focus, and thus does not receive any key events.
If picUser has the focus, your code should work. However, a better way is probably to set your form's KeyPreview property to true, and then put your code above into the form's keyDown event (and set e.Handled = true as well, to prevent the key event from being passed on to whichever control does have the focus).
I have a form with a textbox called 'tbWO.' This field is used to enter a Purchase Order Number. I also have a button control called 'btnFill.' When btnFill is clicked, it fills a dataset with a parameter from 'tbWO.'
I would like to be able to press 'ENTER' in the 'tbWO' textbox (after a Purchase Order # is entered) and have it fire the btnFill_Click event I mentioned above.
I tried with this bit of errant, badly written code - but, it's just not working properly, i.e., at all, or how I think it should work. Anyway, the code is below; in all it's glory.
private void txtWO_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
btnFill.Click += new EventHandler(btnFill_Click);
}
}
I will admit confusion on using 'new EvenHandler( ?? ). Fairly new to C# (as is probably blantantly obvious.)
Any help, links, suggestions - all are greatly appreciated.
Thanks.
Jasoomian
you could do this...
private void txtWO_KeyUp(object sender, KeyEventArgs e) {
if (e.KeyCode == Keys.Enter) {
btnFill_Click();
}
}
As a rule, I abhor mapping one event handler to another. Instead, write a separate function, and have both event handlers invoke that separate function. Something like this:
private void txtWO_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
AcceptInput();
}
}
private void btnFill_Click(object sender, EventArgs e)
{
AcceptInput();
}
private void AcceptInput()
{
// Do clever stuff here when the user presses enter
// in the field, or clicks the button.
}
Granted, you may feel differently, but it accomplishes the same thing, but with (IMO) far more readable code. But it's been my experience that criss-crossing event handlers is very sloppy and leads to maintenance headaches out the wazoo.