C# Try to fire an event to call function - c#

When I press enter, which enables the buttonEditClient_PressEnter function,
the buttonEditClient_ButtonClick function should be called.
private void buttonEditClient_PressEnter(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
//fire buttonEditClient_ButtonClick function
}
}
private async void buttonEditClient_ButtonClick(object sender, ButtonPressedEventArgs e)
{
//buttonEditClient_ButtonClick activated
}
In the Designer:
this.buttonEditClient.ButtonClick += new DevExpress.XtraEditors.Controls.ButtonPressedEventHandler(this.buttonEditClient_ButtonClick);
this.buttonEditClient.KeyDown += new System.Windows.Forms.KeyEventHandler(this.buttonEditClient_PressEnter);
If I try this:
private void buttonEditClient_PressEnter(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
buttonEditClient_ButtonClick(sender, e)
}
}
I get this error:
cannot convert from 'System.Windows.Forms.KeyEventArgs' to 'DevExpress.XtraEditors.Controls.ButtonPressedEventArgs'
How can I activate the buttonEditClient_ButtonClick function?

A click event is inherently different from a keyboard event (e.g., one includes information about the pressed mouse button and cursor position, the other about the pressed key), so you can't pass your KeyEventArgs to the click handler, which expects a ButtonPressedEventArgs.
You have a few simple options here:
Move your code from the button click handler to an extra function, and call that from both your handlers.
Find a way to create a new ButtonPressedEventArgs instance inside the key handler, and then pass that instead of the KeyEventArgs. This would be a very slipshod solution, as you're literally making stuff up (what cursor position are you going to give it?).
The first solution could look something like this:
private void buttonEditClient_PressEnter(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
buttonEditClientSubmit();
}
}
private async void buttonEditClient_ButtonClick(object sender, ButtonPressedEventArgs e)
{
buttonEditClientSubmit();
}
private void buttonEditClientSubmit()
{
// your code...
}

It depends on if you actually need anything from the ButtonPressedEventArgs. If you don't need anything from ButtonPressedEventArgs, you could just have both events call one function.
private void Handle_buttonEditClient()
{
// Do what you want to do when the button is pressed or has the "Enter"
// key pressed on it.
}
private void buttonEditClient_PressEnter(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
Handle_buttonEditClient();
}
}
private void buttonEditClient_ButtonClick(object sender, ButtonPressedEventArgs e)
{
Handle_buttonEditClient();
}
Note
I made buttonEditClick_ButtonClick synchronous, but if you leave it async the same thing applies. Just have both events call the same function.
If you need the ButtonPressedEventArgs, then it's like Anas Alweish says. You'll have to create an instance of ButtonPressedEventArgs. I'm not familiar with DevExpress, so I don't know how you'd do that. Maybe something like new ButtonPressedEventArgs(buttonEditClient)?;
DevExpress Docs on ButtonPressedEventArgs

Related

How do you keyboard focus on a specific item?

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);
}

Why it is not Possible to call textBox1_KeyPress() event from some Button Click event.?

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btn0_Click(object sender, EventArgs e)
{
MessageBox.Show("called btn 0 click..");
KeyPressEventArgs e0 = new KeyPressEventArgs('0');
textBox1_KeyPress(sender, e0);
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
MessageBox.Show("called txtbox_keypress event...");
}
}
Am sorry if this is a silly question,I have just started to learn windows forms, I still find material on the internet confusing.I want to implement calculator. So when number button is pressed it should be filled in textbox. So I thought calling textBox1_keypress() event from button click event would work??? but its not working,
I can manually write the logic in button click event to fill text in text box but if i do so, i have to do the same thing in button1_KeyPress event too. so it would be duplication of code right??...so i thought solution was to call textBox1_KeyPress() event from both button click event and button key press event...but its not working .So what should i do???..is there any other approach which should i follow.
so it would be duplication of code right??
Yes, it would be. So you can do
private void btn0_Click(object sender, EventArgs e)
{
CommonMethod(e);
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
CommonMethod(e);
}
private void CommonMethod(EventArgs e)
{
//Your logic here.
}
The TextBox KeyPress event handler (textBox1_KeyPress) is called after the user presses a key. The KeyPressEventArgs parameter includes information such as what key was pressed. So calling it from your btn0_Click method isn't going to set the text for the TextBox.
Rather, you want to (probably) append whatever number the user pressed to the text already present in the TextBox. Something like
private void btn0_Click(object sender, EventArgs e)
{
textBox1.Text += "0";
}
might be closer to what you're trying to accomplish.
You could put the logic in an extra function like so:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btn0_Click(object sender, EventArgs e)
{
NumberLogic(0),
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
// I don't know right now if e contains the key pressed. If not replace by the correct argument
NumberLogic(Convert.ToInt32(e));
}
void NumberLogic(int numberPressed){
MessageBox.Show("Button " + numberPressed.ToString() + " pressed.");
}
}
You don't want to tie the events together like that.
A key-press is one thing, handled in one way.
A button click is something totally different and should be handled as such.
The basic reason is this,
The button doesn't know what number it is, you need to tell it that.
A key-press on the other hand, knows what number was pressed.
If you REALLY want to, for some reason, you could use SendKeys to trigger your key-press event in a round-about way, from the button.
SendKeys.SendWait("0");
I can suggest to you to use an Tag Property of the Buttons. Put in it the value of each button in Design mode or in Constructor, create one button event handler for all buttons and use Tag value:
Constructor:
button1.Tag = 1;
button2.Tag = 2;
button1.Click += buttons_Click;
button2.Click += buttons_Click;
Event hadler:
private void buttons_Click(object sender, EventArgs e)
{
textBox1.Text = ((Button)sender).Tag.ToString();
}

An error when trying to do key press event in C#

I add a key press event
private void listView_KeyPress(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Delete)
{
DeleteContact();
}
}
The framework automatically creates the class for it:
this.listView.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.listView_KeyPress);
When compiling I get an error on System.Windows.Forms.KeyPressEventHandler(this.listView_KeyPress)
No overload for 'listView_KeyPress' matches delegate 'System.Windows.Forms.KeyPressEventHandler' D:\...\MainForm.Designer.cs
I would appreciate any helpful answer, thanks.
The KeyPress event needs the parameter KeyPressEventArgs instead of KeyEventArgs.
However the KeyPress event only gives you the character of the key you pressed. And the DELETE key has no character. Therefor you should use the event KeyDown instead, as this one is gives you the KeyCode instead:
this.listView.KeyDown+= new System.Windows.Forms.KeyPressEventHandler(this.listView_KeyDown);
private void listView_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Delete)
{
DeleteContact();
}
}
Your signature is wrong. The e parameter in your handler shoudl be KeyPressEventArgs not KeyEventArgs
The KeyPressEventHandler delegate expects the second parameter to be a KeyPressEventArgs object, not KeyEventArgs:
private void listView_KeyPress(object sender, KeyPressEventArgs e)
If you need to use information found in KeyEventArgs, you should instead use the KeyDown event. If so, be aware that the KeyDown event can be raised several times, if the user keeps the key pressed.
See
KeyPressEventHandler
private void listView_KeyPress(object sender, KeyEventArgs e)
has to be changed to
private void listView_KeyPress(object sender, KeyPressEventArgs e)

Fire button event manually

I have a search text box on my WPF Windows. Whenever, the user presses enter key after writing some query in the textBox, the process should start.
Now, I also have this Search button, in the event of which I perform all this process.
So, for a texBox:
<TextBox x:Name="textBox1" Text="Query here" FontSize="20" Padding="5" Width="580" KeyDown="textBox1_KeyDown"></TextBox>
private void queryText_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Return)
{
//how do I fire the button event from here?
}
}
It is possible but rather move your search logic into a method such as DoSearch and call it from both locations (text box and the search button).
Are you talking about manually invoking buttonSearch_onClick(this, null);?
You can Create a Common Method to do search for ex
public void MySearch()
{
//Logic
}
Then Call it for diffetnt places you want like...
private void queryText_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Return)
{
MySearch();
}
}
private void buttonSearch_onClick(object sender, EventArgs e)
{
MySearch();
}
A event can not be fired/raised from outside the class in which it is defined.(Using reflection you can definitely do that, but not a good practice.)
Having said that, you can always call the button click event handler from the code as simple method call like below
private void queryText_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Return)
{
OnSearchButtonClick(SearchButton, null);
}
}

Wire _KeyDown event of textbox to a _click event of button control

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.

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