I'm using the following piece of code, for documentation, error handling and/or logging. It's saves an image of the UserControl or Form when I click it pressing Control+Alt+Shift:
public Image GetImage()
{
Bitmap oBmp = new Bitmap(this.Width, this.Height);
this.DrawToBitmap(oBmp, new Rectangle(0, 0, oBmp.Width, oBmp.Height));
return (Image)oBmp;
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
bool bControl = false;
bool bShift = false;
bool bAlt = false;
bControl = (Control.ModifierKeys & Keys.Control) == Keys.Control;
bShift = (Control.ModifierKeys & Keys.Shift) == Keys.Shift;
bAlt = (Control.ModifierKeys & Keys.Alt) == Keys.Alt;
if (bControl && bShift && bAlt)
{
GetImage().Save(this.Name.TimedLocalFileName("png"), ImageFormat.Png);
}
}
Right now, I'm coding it in every UserControl, in the base form and so. It's easy to do because I'm using a code Snippet. But it has obvious setbacks.
The same piece of code in a lot of places (maintainability); and
Works only when I click on the base control and not it's childs (if an UserControl has a Label, this doesn't works.
I've been for a few days analyzing GlobalHooks (mostly here: CodeProject, but my head is not helping me.
Any suggestion will be very much appreciated.
Note: TimedLocalFileName is an extension method that returns a String in format <ControlName>_<Culture>_<YYYYMMDD>_<HHMMSS>.<FileExtension>
Create a base UserControl and name it BaseUserControl and derive all your user control from BaseUserControl then you can put all the logic inside the base user control.
Inside the BaseUserControl, using a recursive method, handle MouseDown event of all child controls and redirect them to OnMouseDown of this, like this post.
Override OnHanldeCrated and call that recursive method to wire up events.
Here is the base control:
using System;
using System.Drawing;
using System.Windows.Forms;
public class BaseUserControl : UserControl
{
void WireMouseEvents(Control container)
{
foreach (Control c in container.Controls)
{
c.MouseDown += (s, e) =>
{
var p = PointToThis((Control)s, e.Location);
OnMouseDown(new MouseEventArgs(e.Button, e.Clicks, p.X, p.Y, e.Delta));
};
WireMouseEvents(c);
};
}
Point PointToThis(Control c, Point p)
{
return PointToClient(c.PointToScreen(p));
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
if (Control.ModifierKeys == (Keys.Control | Keys.Alt | Keys.Shift))
MessageBox.Show("Handled!");
// Your custom logic
}
protected override void OnHandleCreated(EventArgs e)
{
base.OnHandleCreated(e);
WireMouseEvents(this);
}
}
Answering issue 1
The same piece of code in a lot of places (maintainability)
It's not always applicable but if you find yourself using this behavior a lot, you could inherit from UserControl to create BitmapExportUserControl and put Image GetImage() and override void OnMouseDown(MouseEventArgs e) in this class instead, and make all your custom controls that need this behavior inherit from BitmapExportUserControl.
Another way could to perform the bitmap export from your Form itself, and have your Form subscribe to all the MouseDown events of all its children Control objects.
Answering issue 2
Works only when I click on the base control and not it's childs
As far as I know, there is no built-in "up" event propagation (or bubbling) in WinForms as there is in WPF for example. A solution could be to expose an event that can be raised by all UserControl in your application when there is a MouseDown event on them. Your code would become:
protected override void OnMouseDown(MouseEventArgs e)
{
GlobalMouseDown.RaiseGlobalMouseDownEvent(this, e);
}
and you would have your main Form subscribe to this GlobalMouseDown.GlobalMouseDownEvent and perform the checks and bitmap export.
This is functionally equivalent to having a public method HandleMouseDown in some GlobalMouseDown class that would be called by all your UserControl MouseDownEventHandlers. The code in each UserControl would become:
protected override void OnMouseDown(MouseEventArgs e)
{
GlobalMouseDown.HandleMouseDown(this, e);
}
and you would do your checks and bitmap export in this method.
Related
I am continuing to program some kind of keyboard navigation in my simple graphic program (using C#). And I ran into trouble once again.
My problem is that I want to process the keyboard input to move a layer around. Moving the layer with the mouse already works quite well, yet the control doesn't get the focus (neither KeyUp/KeyDown/KeyPress nor GotFocus/LostFocus is triggered for this control).
Since my class derives from Panel (and overwrites a couple of events), I've also overwritten the events mentioned above, but I can't succeed in getting those events triggered.
I think I could manage to implement keyboard response either using something like Keyboard.GetState() or ProcessCmdWnd or something. However: I still have to be able to tell when the control got the focus.
Is there an more or less elegant way to add this ability to a user control (which is based on Panel)?
I've checked many threads in here and I might use this approach for keyboard input. The focus problem however still remains.
Thank you very much for information in advance!
Igor.
p.s.: I am programming in C# .NET v3.5, using VS2008. It's a Windows.Forms application, not WPF.
The Panel class was designed as container, it avoids taking the focus so a child control will always get it. You'll need some surgery to fix that. I threw in the code to get cursor key strokes in the KeyDown event as well:
using System;
using System.Drawing;
using System.Windows.Forms;
class SelectablePanel : Panel {
public SelectablePanel() {
this.SetStyle(ControlStyles.Selectable, true);
this.TabStop = true;
}
protected override void OnMouseDown(MouseEventArgs e) {
this.Focus();
base.OnMouseDown(e);
}
protected override bool IsInputKey(Keys keyData) {
if (keyData == Keys.Up || keyData == Keys.Down) return true;
if (keyData == Keys.Left || keyData == Keys.Right) return true;
return base.IsInputKey(keyData);
}
protected override void OnEnter(EventArgs e) {
this.Invalidate();
base.OnEnter(e);
}
protected override void OnLeave(EventArgs e) {
this.Invalidate();
base.OnLeave(e);
}
protected override void OnPaint(PaintEventArgs pe) {
base.OnPaint(pe);
if (this.Focused) {
var rc = this.ClientRectangle;
rc.Inflate(-2, -2);
ControlPaint.DrawFocusRectangle(pe.Graphics, rc);
}
}
}
The code from Hans Passant translated to VB.NET
Imports System
Imports System.Drawing
Imports System.Windows.Forms
Public Class SelectablePanel
Inherits Panel
Public Sub New()
Me.SetStyle(ControlStyles.Selectable, True)
Me.TabStop = True
End Sub
Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
Me.Focus()
MyBase.OnMouseDown(e)
End Sub
Protected Overrides Function IsInputKey(ByVal keydata As Keys) As Boolean
If (keydata = Keys.Up OrElse keydata = Keys.Down) Then Return True
If (keydata = Keys.Left OrElse keydata = Keys.Right) Then Return True
Return MyBase.IsInputKey(keydata)
End Function
Protected Overrides Sub OnEnter(ByVal e As EventArgs)
Me.Invalidate()
MyBase.OnEnter(e)
End Sub
Protected Overrides Sub OnLeave(ByVal e As EventArgs)
Me.Invalidate()
MyBase.OnLeave(e)
End Sub
Protected Overrides Sub OnPaint(ByVal pe As PaintEventArgs)
MyBase.OnPaint(pe)
If (Me.Focused) Then
Dim rc As Rectangle = Me.ClientRectangle
rc.Inflate(-2, -2)
ControlPaint.DrawFocusRectangle(pe.Graphics, rc)
End If
End Sub
End Class
call focus in click event
private void Panel_Click(object sender, EventArgs e)
{
Panel.Focus();
}
To get the focus,check for MouseEnter event in Properties window.
Write below code:
private void mainPanel_MouseEnter(object sender, EventArgs e)
{
mainPanel.Focus();
}
The simplest trick I use when for any reason I can’t use the parent Form KeyPreview property to make the Form handle key events, is to put a Textbox on
The panel:
Panel.Controls.Add(_focusTextBox = new TextBox() { Visible = true , Left = -300, TabIndex = 0});
And use it to capture KeyDown event:
_focusTextBox.KeyDown += panel_KeyDown;
The last step is to set focus to this TextBox when other controls on the panel clicked:
_focusTextBox.Focus();
Panels are not getting focus, you have to select the panel if you want to track leave and enter events
call panel1.Select() in MouseClick Event
The default winforms Button control only draws itself in a "clicked state" when the user left clicks the button. I need the Button control to draw itself in the clicked state regardless of it was left clicked or right clicked. How would I accomplish this?
More specifically, I know I will need to derive a control from Button which extends the functionality, but I have no experience in extending functionality of winforms controls or drawing in GDI+. So I'm a little dumbfounded on what exactly I'll need to do once in there.
Thanks for the help.
Standard button control sets the button in down and pressed mode using a private SetFlag method. You can do it yourself too. I did it in following code:
using System.Windows.Forms;
public class MyButton : Button
{
protected override void OnMouseDown(MouseEventArgs e)
{
SetPushed(true);
base.OnMouseDown(e);
Invalidate();
}
protected override void OnMouseUp(MouseEventArgs e)
{
SetPushed(false);
base.OnMouseUp(e);
Invalidate();
}
private void SetPushed(bool value)
{
var setFlag = typeof(ButtonBase).GetMethod("SetFlag",
System.Reflection.BindingFlags.Instance |
System.Reflection.BindingFlags.NonPublic);
if(setFlag != null)
{
setFlag.Invoke(this, new object[] { 2, value });
setFlag.Invoke(this, new object[] { 4, value });
}
}
}
Similar questions have been already asked (e.g., here), however I've not found an answer for my specific case. I'm building a custom control based on a DevExpress control, which in turns is based on standard TextBox and I've a flickering problem that seems due to the base TextBox component, which tries to update selection.
Without explaining all the details of my custom control, to reproduce the problem you just need to place a TextBox inside a Form and then use this code:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
textBox1.MouseMove += TextBox1_MouseMove;
}
private void TextBox1_MouseMove(object sender, MouseEventArgs e) {
(sender as TextBox).Text = DateTime.Now.Ticks.ToString();
}
}
If you launch it, you click on the TextBox and then you move the cursor toward right you will notice the flickering problem (see video here). For my custom control I would need to avoid this flickering. I'm bound to use a TextBox (so no RichTextBox). Any idea?
The solution has been provided in the meantime by Reza Aghaei by overriding WndProc and intercepting WM_SETFOCUS messages. See here
Depending on what u want to do there are several solutions:
If you want to prevent the selection it would be:
private void TextBox1_MouseMove(object sender, MouseEventArgs e)
{
(sender as TextBox).Text = DateTime.Now.Ticks.ToString();
(sender as TextBox).SelectionLength = 0;
}
Or for selecting all:
private void TextBox1_MouseMove(object sender, MouseEventArgs e)
{
(sender as TextBox).Text = DateTime.Now.Ticks.ToString();
(sender as TextBox).SelectAll();
}
And besides that u also could specify the conditions for selecting, for example:
private void TextBox1_MouseMove(object sender, MouseEventArgs e)
{
(sender as TextBox).Text = DateTime.Now.Ticks.ToString();
if (MouseButtons == MouseButtons.Left) (sender as TextBox).SelectAll();
else (sender as TextBox).SelectionLength = 0;
}
But as long as you want to select the text you always will get some flickering, because a normal Textbox has not the possibility to use things like BeginEdit and EndEdit and so it will change the text first and then select it.
Looking at the video it looks like your textbox is calling WM_ERASEBKGND unnecessarily. In order to remedy this problem you can subclass the textbox class and intercept these messages. Below is sample code which should do the trick (untested) Disclaimer: I have used this technique for other WinForm controls that had the type of flicker shown in your video but not TextBox. If it does work for you, please let me know. Good luck!
// textbox no flicker
public partial class TexttBoxNF : TextBox
{
public TexttBoxNF()
{
}
public TexttBoxNF(IContainer container)
{
container.Add(this);
InitializeComponent();
//Activate double buffering
this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
//Enable the OnNotifyMessage event so we get a chance to filter out
// Windows messages before they get to the form's WndProc
this.SetStyle(ControlStyles.EnableNotifyMessage, true);
}
//http://stackoverflow.com/questions/442817/c-sharp-flickering-listview-on-update
protected override void OnNotifyMessage(Message m)
{
//Filter out the WM_ERASEBKGND message
if (m.Msg != 0x14)
{
base.OnNotifyMessage(m);
}
}
}
I have multiple custom controls, and I noticed that all of them share the same event (custom) example : OnMoved etc
What I'm doing now is, copy & paste the same code from controls to controls.
So, are there anyway for me to write custom events that can be shared throughout all my controls in C# WPF?
An example of an event that I use for all my controls :
Point lastPosition = new Point();
Point currentPosition = new Point();
public static void OnMoved(object sender, EventArgs e)
{
currentPosition.X = Canvas.GetLeft(explorer);
currentPosition.Y = Canvas.GetTop(explorer);
// didn't moved
if (currentPosition.X == lastPosition.X || currentPosition.Y == lastPosition.Y)
{
return;
}
lastPosition.X = Canvas.GetLeft(explorer);
lastPosition.Y = Canvas.GetTop(explorer);
}
It depends on what exactly you need the event to do, but you could place the event into a shared class:
public class MyEvents
{
public static void SomeEvent(object sender, EventArgs e)
{
MessageBox.Show("hi");
}
}
And then just subscribe to it from wherever you need to:
SomeButton.Click += MyEvents.SomeEvent;
You can create a base class that has a public virtual event, and the event will appear in any classes that derive from the base class. That would keep you from having to copy and paste the same code over and over.
Yes you can! :D The only things you need to have present are:
-> Same Events (The Args of the event have to be exactly the same.
-> They are going to do the same.
The bad thing is that you cannot mix controls with events. For example, you can create a .Click event for a button so it closes your application, but if you wish this to do the same when you press the key "F8" it won't work because the Event arguments are different ~
You can try using a method that makes the same stuff in all your events. Example:
private void _Close()
{
Process.GetCurrentProcess().Close();
}
And you can close with "F5" pressed in the form or with a button click or typyng in a textbox "Close".
button.Click += Button_Close;
private void Button_Close(Object o, RoutedEventArgs e)
{
_Close();
}
this.KeyDown += This_Close;
private void This_Close(Object o, KeyEventArgs e)
{
if(e.KeyCode == Key.F5) _Close();
}
TextBox.TextChanged += Text_Close;
private void Text_Close(Object o, TextChangedEventArgs e)
{
if(TextBox.Text == "Close") _Close();
}
I need to reinvent/recreate the Label Control from scratch to add my own mojoness to it. Yes, I know what you're thinking (and if you're not thinking that, shouldn't you be?).
Can somebody point me in the right direction?
Thank you.
The whole purpose for recreating the label is that I want full control over how it is drawn onto screen, and so that I can have KeyDown Event Handlers for it, too. For example, the user can edit the contents of a label the same way they would edit the contents of a TextBox control.
Also, I cannot just simply use a TextBox control, as it would require almost, if not more work to get my desired result.
Why not just extend the current one?
class MyMojoLabel : Label // Kind of thing
A good starting point would maybe to understand how Microsoft implemented the label.
To get a better in-depth look you should take a look with Reflector into the class or debugging the source code of the Label control.
public class MyLabel : System.Windows.Forms.Label
{
protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
base.OnPaint(e);
// or leave base out
// you would determine these values by the length of the text
e.Graphics.DrawEllipse(new System.Drawing.Pen(System.Drawing.Color.Red),
0, 0, 50, 12);
}
protected override void OnKeyDown(System.Windows.Forms.KeyEventArgs e)
{
base.OnKeyDown(e);
// although a label has a KeyDown event I don't know how it would
// receive focus, maybe you should create a text box that looks
// like a label
}
}
How about this?
Create a class that inherits from Control. Use the SetStyle() call to enable user painting and double-buffering, and override the OnPaint(), and any other methods that you need.
class MyLabel : System.Windows.Forms.Control
{
public MyLabel()
{
this.SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer, true);
}
protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
base.OnPaint(e);
ControlPaint.DrawBorder3D( e.Graphics, this.ClientRectangle, Border3DStyle.Etched, Border3DSide.All);
e.Graphics.DrawString(this.Text, this.Font, Brushes.Red, 0, 0);
}
}
Creating your own label control is simple enough, you just need to start with Control and override OnPaint(). What is going to byte is to turn it into a control that also has focusing behavior. And allows the user to edit the text. By the time you're done, you'll have re-invented the TextBox control. Which is a lot harder than it looks.
Focus on the focusing first, that's the trickiest problem. It isn't very likely that the user will want to focus the control frequently. Maybe some kind of secret handshake, like a double-click. When you detect one, you could create a TextBox control and put it in front of the label. And dispose it when it loses focus, updating the label's Text property. Or a simple context menu that displays a small editing dialog.
An example that uses the double-click to edit approach:
using System;
using System.Windows.Forms;
class MyLabel : Label {
private TextBox mEditor;
protected override void OnDoubleClick(EventArgs e) {
if (mEditor == null) {
mEditor = new TextBox();
mEditor.Location = this.Location;
mEditor.Width = this.Width;
mEditor.Font = this.Font;
mEditor.Text = this.Text;
mEditor.SelectionLength = this.Text.Length;
mEditor.Leave += new EventHandler(mEditor_Leave);
this.Parent.Controls.Add(mEditor);
this.Parent.Controls.SetChildIndex(mEditor, 0);
mEditor.Focus();
}
base.OnDoubleClick(e);
}
void mEditor_Leave(object sender, EventArgs e) {
this.Text = mEditor.Text;
mEditor.Dispose();
mEditor = null;
}
protected override void Dispose(bool disposing) {
if (disposing && mEditor != null) mEditor.Dispose();
base.Dispose(disposing);
}
}