I know the solution on Android
#Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
switch(keyCode){
case KeyEvent.KEYCODE_BACK:
// do something here
return true;
}
return super.onKeyDown(keyCode, event); }
But i cant do it on the forms side. The focus is an Entry so the keyboard is visible and when i press hardware back button (keyboard disappear) i'd like to set my variable value.
Edited:
bool _tapped;
LwTeszt.PropertyChanged += (s, e) =>
{
if (LwTeszt.SelectedItem != null)
{
EntryTeszt.Focus();
}
};
EntryTeszt.Unfocused += EntryTeszt_Unfocus;
private void EntryTeszt_Unfocus(object sender, FocusEventArgs e)
{
_tapped = true;
}
private void ViewCell_Tapped(object sender, EventArgs e)
{
if (_tapped)
{
EntryTeszt.Unfocus();
_tapped = false;
return;
}
EntryTeszt.Focus();
}
Unless you have additional logic that you didn't post I think you might be overcomplicating things. I believe all you need to do is focus your entry on ViewCell_Tapped
private void ViewCell_Tapped(object sender, EventArgs e)
{
EntryTeszt.Focus();
}
Forms will handle unfocusing your Entry for you when back is pressed and in that case you won't need the LwTeszt.PropertyChanged, _tapped, and the EntryTeszt.Unfocused parts.
There is an Event you have to just override that and you can handle back button in Xamarin forms. Use below code for handling back button:
protected override bool OnBackButtonPressed()
{
// your code
return base.OnBackButtonPressed();
}
Also you can refer this question for more information.
Related
private void MeretOK_Click(object sender, EventArgs e)
{
//code
}
private void MeretTB_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode==Keys.Enter)
{
MeretOK_Click();
}
}
How can I start an event with a hotkey?
(I know I can just copy the code there but that is ugly)
If I just copy the code and run it I hear a beep. Why?
First, you have to allow your form to handle key events globally (set the form KeyPreview property to true) and to mark your event as internally handled. Second, if the purpose of this code is to simulate the mouse click on a specific control (programmatic click), for example a button, there is an easier way to accomplish it:
private void MeretTB_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
e.Handled = true;
myButton.PerformClick();
}
}
I want to check if the Clipboard consists of a data and if not, let the "Paste" Button be enabled. But unfortunately, even after I clear the Clipboard it still doesn't show it's null. I am working with Windows Forms.
I manually clear the clipboard:
private void button2_Click(object sender, EventArgs e)
{
Clipboard.Clear();
}
and then I add the following code to the Form LoadEvent:
if (Clipboard.GetDataObject() != null)
{
this.pn1_BtnPaste.Enabled = true;
}
And it makes a button enabled which is weird to me. Can anybody explain why is that happening?
EDIT:
Because I got understood wrong, let me change the code to make it more clear:
private void button2_Click(object sender, EventArgs e)
{
Clipboard.Clear();
if (Clipboard.GetDataObject() != null)
{
this.pn1_BtnPaste.Enabled = true;
}
else
this.pn1_BtnPaste.Enabled = false;
}
I click the "button2" and the "pn1_BtnPaste" is enabled anyway.
Data can appear on the clipboard at any time. The Application.Idle event is a decent way to update the button state:
public Form1() {
InitializeComponent();
Application.Idle += Application_Idle;
}
You have to unsubscribe it again when the window closes to be on the safe side:
protected override void OnFormClosed(FormClosedEventArgs e) {
Application.Idle -= Application_Idle;
base.OnFormClosed(e);
}
Clipboard.GetDataObject() does not work the way you think it does, it never returns null. If you want to handle any data then you can write the event handler like this:
private void Application_Idle(object sender, EventArgs e) {
PasteButton.Enabled = Clipboard.GetDataObject().GetFormats().Length > 0;
}
But it is pretty likely you'll find out that handling every possible format is lot let practical than you assumed.
I've got the code, and all seems correct, I've had it reviewed and it seems impossible to find out why the button isn't doing what its coded to do. I'm making a Music player, and when I press the play button, it will be sent to the back and the pause button will become visible, when I next click the pause button, nothing happens and its primary function stops working all together. Here is the code for people to examine.
private void btnPlay_Click(object sender, EventArgs e)
{
try
{
if (_mp3Player != null)
_mp3Player.Play();
btnPlay.SendToBack();
btnPause.BringToFront();
}
catch (Win32Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void btnPause_Click(object sender, EventArgs e)
{
if (_mp3Player != null)
_mp3Player.Stop();
btnPause.SendToBack();
btnPlay.BringToFront();
}
Perhaps it would be best to use visibility?
private void btnPause_Click(object sender, EventArgs e)
{
if (_mp3Player != null)
{
_mp3Player.Stop();
}
btnPause.Visible = False;
btnPlay.Visible = True;
}
Or even the enabled property?
... btnPause.Enabled = false; ...
However I feel you could make it better by having it be the same button, with a value, so just have a value on it of true if it's player or false if it's pause and then in the click event check against that value to determine what it is currently and then just execute the relevant functionality and change the text or image that you have on the button.
i have an application here in winforms that am trying to make. This is how i want it to happen: whenever the user clicks on register visitor button the registration form should be opening. works fine. here is the function that is called in that case:
private void Register_Visitor_Load(object sender, EventArgs e)
On this form i have a textfield placed which i want to disable when the form loads. i wrote a line which disables the textbox on form load:
textbox1.enabled = false;
i placed the above line in the load function which is working fine. now i want to enable my textbox1 based on the checkbox checked. for this i wrote the code:
CheckState state = checkBox1.CheckState;
switch (state)
{
case CheckState.Checked:
{
textBox1.Enabled = true;
break;
}
case CheckState.Indeterminate:
case CheckState.Unchecked:
{
break;
}
now when i place the code above in the page load function nothing happens which is surely going to happen as that function is only called on form load. what am not getting is where to place the checkbox code so that my textbox is enable on runtime. other function are in response to button but what i want here it to instantly enable the textfield on runtime when the user checks the checkbox. kindly explain me how am i going to accomplish this!
You can use CheckStateChanged event; so whatever reason the checkBox1 is checked/unchecked/grayed you'll have the textBox1 properly enabled/disabled
private void checkBox1_CheckStateChanged(object sender, EventArgs e) {
textBox1.Enabled = (checkBox1.CheckState == CheckState.Checked);
}
you are placing code at wrong event.
Instead of placing in pageload place that code on chekchange event of checkbox.
That will help you.
private void chkDisable_CheckedChanged(object sender, EventArgs e)
{
if (((CheckBox)sender).Checked)
{
textBox1.Enable=true;
}
else
{
textBox1.Enable=false;
}
}
Place the above code inside the function which handles the event for check box.
In your case it is checkchanged status.
You can try this:
private void checkBox1_Click(object sender, EventArgs e)
{
if (checkBox1.Checked)
{
textBox1.Enabled = false;
}
else
{
textBox1.Enabled = true;
}
}
I did a hybrid of some of the above answers and it worked perfectly. I wanted the state of a button to be disabled upon loading the form, but then enabled if the user checks a box, here's the code:
private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
button1.Enabled = (checkBox1.CheckState == CheckState.Checked);
}
private void Form1_Load(object sender, EventArgs e)
{
if (checkBox1.Checked)
{
button1.Enabled = true;
}
else
{
button1.Enabled = false;
}
}
I want to give a textbox focus when the user starts typing anywhere in my app.
My page inherits from LayoutAwarePage.
Can this be achieved ?
Edit:
I got this code:
// In constructor
Window.Current.CoreWindow.KeyDown += CoreWindow_KeyDown;
// Somewhere else in class
void CoreWindow_KeyDown(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.KeyEventArgs args)
{
this.setSearchboxFocus((int)args.VirtualKey);
}
private void setSearchboxFocus(int keyCode)
{
if (keyCode == 38)
return;
if (keyCode == 40)
return;
if (this.searchBox.FocusState == Windows.UI.Xaml.FocusState.Unfocused)
{
this.searchBox.Text = "";
this.searchBox.Focus(Windows.UI.Xaml.FocusState.Keyboard);
}
}
For anyone reading this thread in the future, it is because of the webview. I asked a similar question on the msdn forum here. As of Windows 8.1, the webview is implemented as a separate window and completely steals all keyboard input when it has focus without passing any of it up to the controlling application. If you are able to change the HTML in the website being called it may be possible to use javascript listeners to pass events between the application and webview, but I did not test this myself. Unfortunately there does not seem to be any other workaround at this time.
You can handle the KeyDown/KeyUp event for the whole page by subscribing to these events
Window.Current.CoreWindow.KeyDown += CoreWindow_KeyDown;
Window.Current.CoreWindow.KeyUp += CoreWindow_KeyUp
This might help
private void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
textBox1.Focus();//sets focus to textBox1 when user presses a key on form
}
How about something like this?
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (!textBox1.Focused)
{
textBox1.Focus();
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
How about, on the Windows.UI.Xaml.Controls.Page:
protected override void OnKeyDown(KeyRoutedEventArgs e)
{
textBox1.Focus(Windows.UI.Xaml.FocusState.Keyboard);
base.OnKeyDown(e);
}