I have a .NET UserControl (FFX 3.5). This control contains several child Controls - a Panel, a couple Labels, a couple TextBoxes, and yet another custom Control. I want to handle a right click anywhere on the base Control - so a right click on any child control (or child of a child in the case of the Panel). I'd like to do it so that it's maintainable if someone makes changes to the Control without having to wire in handlers for new Controls for example.
First I tried overriding the WndProc, but as I suspected, I only get messages for clicks on the Form directly, not any of its children. As a semi-hack, I added the following after InitializeComponent:
foreach (Control c in this.Controls)
{
c.MouseClick += new MouseEventHandler(
delegate(object sender, MouseEventArgs e)
{
// handle the click here
});
}
This now gets clicks for controls that support the event, but Labels, for example, still don't get anything. Is there a simple way to do this that I'm overlooking?
If the labels are in a subcontrol then you'd have to do this recursively:
void initControlsRecursive(ControlCollection coll)
{
foreach (Control c in coll)
{
c.MouseClick += (sender, e) => {/* handle the click here */});
initControlsRecursive(c.Controls);
}
}
/* ... */
initControlsRecursive(Form.Controls);
To handle a MouseClick event for right click on all the controls on a custom UserControl:
public class MyClass : UserControl
{
public MyClass()
{
InitializeComponent();
MouseClick += ControlOnMouseClick;
if (HasChildren)
AddOnMouseClickHandlerRecursive(Controls);
}
private void AddOnMouseClickHandlerRecursive(IEnumerable controls)
{
foreach (Control control in controls)
{
control.MouseClick += ControlOnMouseClick;
if (control.HasChildren)
AddOnMouseClickHandlerRecursive(control.Controls);
}
}
private void ControlOnMouseClick(object sender, MouseEventArgs args)
{
if (args.Button != MouseButtons.Right)
return;
var contextMenu = new ContextMenu(new[] { new MenuItem("Copy", OnCopyClick) });
contextMenu.Show((Control)sender, new Point(args.X, args.Y));
}
private void OnCopyClick(object sender, EventArgs eventArgs)
{
MessageBox.Show("Copy menu item was clicked.");
}
}
Related
For instance, I want all my text boxes to respond to Ctrl-A by selecting all text. I see several options:
Add an event handler to all the text boxes that takes care of the keyboard shortcuts
Subclass TextBox and replace all my text boxes with it
Create a user control that wraps TextBox and replace all my text boxes with it
However all of these involve changing each and every text box in the app. Is there any sort of thing I could do globally to all text boxes via one action to accomplish this? I kind of doubt it but I thought it wouldn't hurt to ask! (I mean, I suppose now that .NET is open source I could build a custom framework, but that's definitely overkill!)
I have a idea about that. The first step is get all controls of a control. Like this method:
public static IEnumerable<Control> GetAllControls(Control container)
{
List<Control> controlList = new List<Control>();
foreach (Control c in container.Controls)
{
controlList.AddRange(GetAllControls(c));
controlList.Add(c);
}
return controlList;
}
You can improve this method to get just the TextBox's.
So, now you have all the TextBoxes that you want. You can add a event for each, something like that:
foreach( var textBox in textBoxList )
{
textBox.KeyPress += MeyKeyPressEvento_KeyPress;
}
Or you can put that event int your form and select all TextBoxes.
I hope you can get a mindset with my answer. Good luck 🖖🏻
Dynamically attach your events when you load your form.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
// iterate all controls on the form
foreach (Control control in this.Controls)
{
if (control is TextBox textBox)
{
// attach your event's method
textBox.KeyDown += OnKeyDown_SelectAllText;
}
}
}
private void OnKeyDown_SelectAllText(object sender, KeyEventArgs e)
{
if (e.Control && e.KeyCode == Keys.A)
{
TextBox textBox = (TextBox) sender;
textBox.SelectAll();
}
}
// be sure to detach all events when done with form
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
foreach (Control control in this.Controls)
{
TextBox textBox = control as TextBox;
if (textBox != null)
{
textBox.KeyDown -= OnKeyDown_SelectAllText;
}
}
}
}
I have a form with so many controls in it. Currently I have set a cursor for my form:
this.Cursor = TargetCursor;
This cursor will be the default cursor for every control. But I need to change Cursor on mouse over of every control.
How Can I do this without managing mouse over event for every control?
You can iterate through all controls and change their Cursor property. Like this:
public Form1()
{
InitializeComponent();
foreach (Control control in Controls)
{
control.Cursor = Cursors.Hand;
}
}
And to support multi level controls and controls inside containers you can use a recursive method like this:
public Form1()
{
InitializeComponent();
setCursor(Controls);
}
void setCursor(IEnumerable theControls)
{
foreach (Control control in theControls)
{
if (control.HasChildren)
{
setCursor(control.Controls);
}
else
control.Cursor = Cursors.Hand;
}
}
Suppose all controls are in one specific panel called pnlMain, you can use a recursive method to do it all for you.
private void ChangeCursor(Control control)
{
foreach (Control con in control.Controls)
{
con.MouseHover += con_MouseHover;
ChangeCursor(con);
}
}
void con_MouseHover(object sender, EventArgs e)
{
Control ct = (Control) sender;
ct.Cursor = Cursors.Hand;
}
Then call it like:
ChangeCursor(pnlMain);
You could also add event handler for MouseLeave to reset the cursor if you want.
I can't think of a global solution that will work for all Controls without accessing each Control. So this would be a recursive method to set the Cursor for all Controls:
void SetCursorOnControls(Control parent, Cursor cursor)
{
parent.Cursor = cursor;
foreach(Control c in parent.Controls)
SetCursorOnControls(c, cursor);
}
Maybe you'll need a try...catch block around parent.Cursor = cursor since you may iterate into composite controls and find child controls that won't support the Cursor property (I don't think they will through, but I'm not sure).
If you explicitly want to do it only on Mouse events, try that:
void SetCursorEventsOnControls(Control parent, Cursor cursor)
{
parent.MouseEnter += (sender, e) => ((Control)sender).Cursor = cursor;
parent.MouseLeave += (sender, e) => ((Control)sender).Cursor = Cursors.Default;
foreach(Control c in parent.Controls)
SetCursorOnControls(c, cursor);
}
With respect to user2946329's answer/comments, you should call these methods as this
public Form1()
{
InitializeComponents();
foreach(Control c in Controls)
SetCursorOnControls(c, Cursors.Hand); // or SetCursorEventsOnControls
}
So you won't set the Cursor of your Form.
I've got these functions:
private void setupFocusControls(Control parent)
{
foreach (Control control in parent.Controls)
{
control.GotFocus += HandleFocus;
}
}
private void HandleFocus(object sender, EventArgs e)
{
Control control = (Control)sender;
thisFormName = this.Name;
thisControlName = control.Name.ToString();
if (bHelpSystemActive)
{
bHelpSystemActive = false;
if ((ModifierKeys & Keys.Control) == Keys.Control)
{
HelpSystem hs = new HelpSystem(thisFormName, thisControlName);
hs.ShowDialog();
}
else
{
showTooltipForControl(control, thisFormName);
}
return;
}
}
And I call this in the Form_Load function:
private void Labeller_Load(object sender, EventArgs e)
{
setupFocusControls(this);
fillListBox();
}
What this does is show a custom help system I've written. If no control key is clicked, then I'll display the info in a tool tip. If the control key is pressed, then I show an editor. Simple really.
Now, this code works perfectly on another form, which uses panels as containers for my form controls. The problem is, I now want to add this functionality to a separate form. I've added all the code, but none of the controls on the form are having the HandleFocus event added to them. The only difference between this form and the working one is that it uses a splitContainer as it's container.
My question is, why is the setupFocusControls function not looping through the splitContainer as it does the panels on my working form? And, how would I go about fixing it? I'd obviously rather not have several functions to perform this (what I thought) simple task...
Cheers.
Assuming that the problem is that you are not assigning the event to every single control on the form (only top-level controls), the fix should be to change your setupFocusControls(Control) method:
private void setupFocusControls(Control parent)
{
foreach (Control control in parent.Controls)
{
control.GotFocus += HandleFocus;
// add the following line to recurse throughout the control tree
setupFocusControls(control);
}
}
This will add the HandleFocus event handler to every single control, by recursing through the children of every control. I hope this works for you!
As a bonus, if you want to add the event handler to all controls, including the parent control, you could write the setupFocusControls method as follows:
private void setupFocusControls(Control parent)
{
parent.GotFocus += HandleFocus;
foreach (Control child in parent.Children)
setupFocusControls(child);
}
I've form with eight textboxes, and and now I want whenever any user performs textchanged event in any textbox, a button gets disabled.
Should I need to bind to textChanged event to all the textboxes, or is there any better approach?
What if later I want more textboxes in my winforms?
If for some reason you don't want to have to bind the same event handler to 8+ text boxes in the designer, you could do so programatically on the Form load event:
private void MainForm_Load(object sender, EventArgs e)
{
foreach (Control maybeTextBox in Controls)
{
if (maybeTextBox is TextBox)
{
maybeTextBox.TextChanged += new EventHandler(maybeTextBox_TextChanged);
}
}
}
The only problem with this is that if any of the TextBoxes are inside another control, you'll need to write a recursive find method like this:
public static Control[] GetControls(Control findIn)
{
List<Control> allControls = new List<Control>();
foreach (Control oneControl in findIn.Controls)
{
allControls.Add(OneControl);
if (OneControl.Controls.Count > 0)
allControls.AddRange(GetControls(oneControl));
}
return allControls.ToArray();
}
You can call that method on a form, so the original code will become:
foreach (Control maybeTextBox in GetControls(this))
I have a winforms app and the main (and only) form has several buttons. When the user clicks a button, I want all other buttons to be disabled.
I know I could do this the long way by setting "Enabled" to false on all buttons but the one which has been clicked in the clicked event handler of that button, but this is a long and tedious approach.
I got the collection of controls on the form, but this does not include the several buttons I have:
System.Windows.Forms.Control.ControlCollection ctrls = this.Controls;
How can I go about implementing this functionality in a mantainable fashion?
Thanks
DisableControls(Control c)
{
c.Enable = false;
foreach(Control child in c.Controls)
DisableControls(child)
}
private void Form1_Load(object sender, EventArgs e)
{
foreach (Control ctrl in this.Controls)
{
if (ctrl is Button)
{
Button btn = (Button)ctrl;
btn.Click += ButtonClick;
}
}
}
private void ButtonClick(object sender, EventArgs e)
{
foreach (Control ctrl in this.Controls)
{
if (ctrl is Button)
{
Button btn = (Button)ctrl;
if (btn != (Button)sender)
{
btn.Enabled = false;
}
}
}
}
You could use databinding, so you only iterate once on startup:
public partial class Form1 : Form
{
public bool ButtonsEnabled { get; set; }
public Form1()
{
InitializeComponent();
// Enable by default
ButtonsEnabled = true;
// Set the bindings.
FindButtons(this);
}
private void button_Click(object sender, EventArgs e)
{
// Set the bound property
ButtonsEnabled = false;
// Force the buttons to update themselves
this.BindingContext[this].ResumeBinding();
// Renable the clicked button
Button thisButton = sender as Button;
thisButton.Enabled = true;
}
private void FindButtons(Control control)
{
// If the control is a button, bind the Enabled property to ButtonsEnabled
if (control is Button)
{
control.DataBindings.Add("Enabled", this, "ButtonsEnabled");
}
// Check it's children
foreach(Control child in control.Controls)
{
FindButtons(child);
}
}
}
Expanding on Alex Reitbort's answer, here's an example method I just wrote 20 minutes ago for this project I'm doing:
private void Foo(bool enabled)
{
foreach (Control c in this.Controls)
if (c is Button && c.Tag != null)
c.Enabled = enabled;
}
This function is not recursive like his is. However, because I know there are no Buttons within a container other than my form so I don't need to worry about that. If there were child controls (ie controls within a GroupBox for example), I'd probably modify that code to be something like this;
private void ToggleControls()
{
Foo(this.Controls, false) // this being the form, of course.
}
private void Foo(Control.ControlCollection controls, bool enabled)
{
foreach (Control c in controls)
{
if (c is Button && c.Tag != null)
c.Enabled = enabled;
if (c.HasChildren)
Foo(c.Controls, enabled);
}
}
I actually like his method a little more, that style of recursion looks a little cleaner than mine I think. Just showing you an alternate way.
Note; I have 6 buttons on my form and I only want 4 of them to have their Enabled property modified by this method. To accomplish this, I set their Tag property to some random string. That is why I check for c.Tag in my if statements. You can remove that if you know you want to disable every control.