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)
Related
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
I've 5 buttons in my windows application. When I click arrow keys the focus changing between buttons, then only
KeyUp
event firing. How to stop this?
Subscribe to the PreviewKeyDown event instead.
Occurs before the KeyDown event when a key is pressed while focus is on this control.
As you move through the buttons, the sender parameter will contain the previously selected button.
I found a solution that should work for you, adapted from here. Apparently, MS made the decision that the arrow keys wouldn't trigger the KeyDown event, so you can't cancel them.
One workaround is to specify that your arrow keys are normal input keys, like any other key. Then the KeyDown event will fire and you can cancel the button press if you want.
private void button1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (e.KeyCode == Keys.Left || e.KeyCode == Keys.Right || e.KeyCode == Keys.Up || e.KeyCode == Keys.Down)
e.IsInputKey = true;
}
private void button1_KeyDown(object sender, KeyEventArgs e)
{
e.Handled = true;
}
You may want to read the other answers and comments in that post to see what would work best in your situation.
Answer for your question in comment
void button1_LostFocus(object sender, EventArgs e)
{
button1.Focus();
}
To prevent Up from moving focus from a Button you have to utilize at least 3 methods:
bool _focus;
private void button1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (e.KeyCode == Keys.Up)
_focus = true;
}
private void button1_KeyUp(object sender, KeyEventArgs e)
{
_focus = false;
}
private void button1_Leave(object sender, EventArgs e)
{
if(_focus)
button1.Focus(); // or (sender as Control)
}
Trick is to use flag when user press Up and to return focus in Leave. You have to unflag in KeyUp, otherwise it would be impossible to change focus (by pressing Tab to example).
You could possible unflag in Leave, I didn't test it.
I have a problem to how to catch which key is pressed. This is my code, but i cant get what key was pressed. I'm using KeyEventArgs for declaration of new variable and then comparing it.
private void textBox2_TextChanged(object sender, EventArgs e)
{
KeyEventArgs k = null;
if (e is KeyEventArgs)
{
k = (KeyEventArgs)e;
}
if (k.KeyCode == Keys.Enter)
{
// do something here
}
}
You need to add:
[component_name].KeyDown += new System.Windows.Forms.KeyEventHandler(this.Key_Pressed_Method);
into the constructor of your Form. Then, you can define what you want to do in Key_Pressed_Method() method.
TextChanged won't give you a KeyEventArgs. You want KeyUp, KeyDown or KeyPress instead. KeyPress gives you KeyPressEventArgs instead.
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);
}
}
I can't get the Ctrl key state in the KeyUp event handler as the Ctrl key is released.
Do I have to test the keycode of the event argument?
Is there any other way?
Wiring an event to the KeyUp event handler will work.
The following code will trigger when the Ctrl key is released:
private void Form1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.ControlKey)
{
MessageBox.Show("Control key up");
}
}
If you want to test if the Ctrl was pressed in combination with another keystroke, for example: Ctrl+F1 then the following code snippet might apply:
private void Form1_KeyUp(object sender, KeyEventArgs e)
{
if (e.Control && e.KeyCode == Keys.F1)
{
MessageBox.Show("Control + F1 key up");
}
}
Side note: You might have to enable KeyPreview on the form in order to catch all control KeyUp events in a single location.
private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if(e.Modifiers == Keys.Control)
...
}