I am making little Windows Forms Application.
I have PictureBox (parent) and Label (child) in it.
The Parent's Mouse Events are working perfectly, but Mouse events generated by child elements are not reflected on the Parent. The Cursor also changes back to its default (arrow).
Is it possible to pass events generated by child Controls, e.g., the MouseEnter event, to the Parent Control?
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Card.MouseEnter += new EventHandler(Card_MouseEnter);
Card.MouseLeave += new EventHandler(Card_MouseLeave);
Card.MouseDown += new MouseEventHandler(this.Card_MouseDown);
Card.MouseUp += new MouseEventHandler(this.Card_MouseUp);
}
void Card_MouseLeave(object sender, EventArgs e)
{
this.Card.BackgroundImage = ((System.Drawing.Image)(Properties.Resources.card_bg));
this.Rename("Running!");
}
void Card_MouseEnter(object sender, EventArgs e)
{
this.Card.BackgroundImage = ((System.Drawing.Image)(Properties.Resources.card_hover_bg));
}
private void Card_MouseDown(object sender, EventArgs e)
{
this.Card.BackgroundImage = ((System.Drawing.Image)(Properties.Resources.card_click_bg));
}
private void Card_MouseUp(object sender, EventArgs e)
{
this.Card.BackgroundImage = ((System.Drawing.Image)(Properties.Resources.card_hover_bg));
this.Rename("Please Wait...");
}
private void CardName_MouseDown(object sender, MouseEventArgs e)
{
}
void Rename(string args)
{
this.CardName.Text = args;
}
private void CardName_Click(object sender, EventArgs e)
{
}
}
This is what I have This is what I want to achieve
The first animation represents what I have now, the second is what I need to achieve :)
When I'm making pictureBox1.Controls.Add(label1) label1 is
disappearing and I tried bring to front and change color but couldn't
do it. Please if you will have any idea show me in provided code by me
to be understandable for me. Thank you all again and again :)
You'd use code like this, maybe in the Load() event of the Form:
private void Form1_Load(object sender, EventArgs e)
{
Point pt = CardName.Parent.PointToScreen(CardName.Location);
Card.Controls.Add(CardName);
CardName.Location = Card.PointToClient(pt);
}
This keeps the label in the same position as it was, but makes the picturebox the parent.
Not sure where you're going wrong. Here's an example showing it in action. Both the PictureBox (Card) and Label (CardName) are inside a Panel (panel1). Clicking on button2 toggles the visibility of the Card. Clicking on button1 makes Card the Parent of CardName. You can see that at first, only the Card toggles visibility, but after clicking on button1 and setting the Parent, both toggle visibility together since CardName is a Child of Card (it also changes its BackColor to match that of its new Parent):
Code:
public partial class Form1 : Form
{
private void button1_Click(object sender, EventArgs e)
{
Point pt = CardName.Parent.PointToScreen(CardName.Location);
Card.Controls.Add(CardName);
CardName.Location = Card.PointToClient(pt);
}
private void button2_Click(object sender, EventArgs e)
{
Card.Visible = !Card.Visible;
}
}
When I move mouse over label, panel thinks mouse left it and rises
MouseLeave event
Here is how you can tell if the cursor has actually left the BOUNDS of the Panel, as opposed to simply enter a child control within the Panel:
private void panel1_MouseEnter(object sender, EventArgs e)
{
panel1.BackColor = Color.Red;
}
private void panel1_MouseLeave(object sender, EventArgs e)
{
Point pt = panel1.PointToClient(Cursor.Position);
if (!panel1.ClientRectangle.Contains(pt))
{
// we only get in here when the cursor leaves the BOUNDS of panel1
panel1.BackColor = Control.DefaultBackColor;
}
}
First of all, you should build a UserControl as a container for all your objects: it'd make everything simpler (the one I'm using here is actually a UserControl, modified to comply with your current setup).
When a Control other than the PictureBox is interacted with, you can decide whether you want to trigger a similar action on the main Control or perform a different action based on what event has been generated.
▶ When the Mouse Pointer enters you assembled Control, you want to change the default Cursor: then, when one of the Labels raises the Enter event, call the method of the main Control that handles this. An event handler is a method, you can call it.
▶ When a Label is clicked, you don't want to trigger the related action of the main Control: in this case, there's nothing to do, just handle this event and perform the required action.
▶ The Label should be child of the main Control. You're using a PictureBox, which is not a ContainerControl. You can add child controls to it anyway. You need to do this in code, since - as mentioned - the PictureBox is not designed to host Controls, thus you cannot drop one inside it: the Control you drop will be parented with the Container that hosts the PictureBox (your Form, here).
When you set the parent in code, you need to remember that the Location of the child control is relative to the old Parent, so you have to re-define it's position.
E.g: PictureBox.Bounds = (100, 100, 100, 200) / Label.Bounds = (100, 250, 100, 50)
When the PictureBox becomes Parent of your Label, the Label.Location is still (100, 250): so, now, it will be hidden, since it's outside the visible bounds of its new Parent. You have to reposition it in relation to the new host: its new Location should be (0, 150), to keep the previous relative position.
PictureBox.Control.Add(Label);
//[...]
Label.Location = new Point(Label.Left - PictureBox.Left, Label.Top - PictureBox.Top);
=> Label.Location = (100 - 100, 250 - 100) => (0, 150)
Or, centered horizontally:
Label.Location = new Point((PictureBox.Width - Label.Width) / 2, Label.Top - PictureBox.Top);
=> Label.Location = ((100 - 100) / 2, 250 - 100) => (0, 150) // <- Since both have the same Width
Or, using positions relative to the Screen:
var p = Label.PointToScreen(Point.Empty); // Relative to the ClientRectangle (Top/Left = (0, 0))
PictureBox.Controls.Add(Label);
Label.Location = PictureBox.PointToClient(p);
In any case, call BringToFront() after, to ensure that the new child Control is brought on top and anchor the Control, so it will keep its position and its Width will be bound to the Parent Width:
Label.BringToFront();
Label.Anchor = AnchorStyles.Left | AnchorStyles.Bottom | AnchorStyles.Right;
Now, assuming you want to change the Cursor to Cursors.Hand when the Mouse enters your combined Control and reset to default when it leaves it:
▶ You want the Cursor to change shape in any case.
▶ You want to generate different actions when the PictureBox is clicked and when one of the Labels is clicked.
▶ Both Labels can have distinct actions when clicked.
→ In the visual sample, the Label above the PictureBox is named lblTitle, the Label inside the PictureBox, at the bottom, is named lblFooter.
→ The PictureBox is named ImageView.
Setup the handlers:
NOTE: With a UserControl, the events handling, e.g., in relation to MouseEnter, changes in:
// The Parent's MouseEnter calls OnMouseEnter
protected override void OnMouseEnter(EventArgs e)
{
base.OnMouseEnter(e);
this.Cursor = Cursors.Hand;
}
// Child Controls just call the same method
private void Labels_MouseEnter(object sender, EventArgs e) => OnMouseEnter(e);
public Form1()
{
InitializeComponent();
Point p = lblFooter.PointToScreen(Point.Empty);
ImageView.Controls.Add(lblFooter);
lblFooter.Location = ImageView.PointToClient(p);
ImageView_MouseEnter += ImageView_MouseEnter;
ImageView_MouseLeave += ImageView_MouseLeave;
// Not added in the code here, do whatever is needed with this handler
ImageView_Click += ImageView_Click;
lblFooter.MouseEnter += Labels_MouseEnter;
lblFooter.MouseLeave += Labels_MouseLeave;
lblFooter.MouseClick += lblFooter_MouseClick;
lblTitle.MouseEnter += Labels_MouseEnter;
lblTitle.MouseLeave += Labels_MouseLeave;
lblTitle.MouseDown += lblTitle_MouseDown;
lblTitle.MouseUp += lblTitle_MouseUp;
}
private void ImageView_MouseEnter(object sender, EventArgs e) => this.Cursor = Cursors.Hand;
private void ImageView_MouseLeave(object sender, EventArgs e) => this.Cursor = Cursors.Default;
private void Labels_MouseEnter(object sender, EventArgs e)
{
ImageView_MouseEnter(ImageView, e);
// [...]
// Do stuff related to the Labels Enter event
}
private void Labels_MouseLeave(object sender, EventArgs e) {
ImageView_MouseLeave(ImageView, e);
}
private void lblTitle_MouseDown(object sender, MouseEventArgs e) {
// Perform actions when the Mouse button is held down lblTitle
}
private void lblTitle_MouseUp(object sender, MouseEventArgs e) {
// Perform actions when the Mouse button is released
}
private void lblFooter_MouseClick(object sender, MouseEventArgs e) {
// Perform actions on a Mouse Click event on lblFooter
}
I'm in the stages of making a program which will require a tabpage to flash when an event happens
I've googled around, and i came across this: Blink tab header on receiving event. This is similar, but uses WPF, and i'm using WinForms, and i'm not even sure that does what i want :L
I've also found this: C#: Flash Window in Taskbar via Win32 FlashWindowEx. This is what i want, but obvious for the whole form, and in the taskbar, not 'in form'
Anyone got any ideas?
I'm not saying this is the best way or even a great way to accomplish this, but it does work. I've used code similar to this when I needed to something similar.
The tabControl1 has two tabs and I blink tab 1 (the second tab).
For my example that I threw together, I set tabControl1's DrawMode property to "OwnerDrawFixed" and then a couple of buttons which start/stop the timer. The interval was something like 750ms but you could choose whatever, of course. On a timer1_Tick event, I swap out the current color and tell the tabControl1 to refresh itself. That'll make the DrawItem event get raised and then I either draw the rectangle the current color if it is tab page 1 or the backcolor if not. Then I draw the tabpage's text.
It works. Could use some tweaking for sure. Give it a whirl!
public partial class Form1 : Form
{
Color currentColor = Color.Green;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
if (currentColor == Color.Yellow)
currentColor = Color.Green;
else
currentColor = Color.Yellow;
tabControl1.Refresh();
}
private void button2_Click(object sender, EventArgs e)
{
timer1.Stop();
}
private void tabControl1_DrawItem(object sender, DrawItemEventArgs e)
{
if (timer1.Enabled && e.Index == 1)
{
e.Graphics.FillRectangle(new SolidBrush(currentColor), e.Bounds);
}
else
{
e.Graphics.FillRectangle(new SolidBrush(this.BackColor), e.Bounds);
}
Rectangle paddedBounds = e.Bounds;
paddedBounds.Inflate(-2, -2);
e.Graphics.DrawString(tabControl1.TabPages[e.Index].Text, this.Font, SystemBrushes.HighlightText, paddedBounds);
}
}
I'm making a C# WinForms application. The MouseMove and MouseClick events of the form aren't getting fired for some reason. (I'm probably going to feel like an idiot when I find out why.)
It is a transparent form (TransparencyKey is set to the background colour) with a semi-transparent animated gif in a Picture Box. I am making a screensaver.
Any suggestions?
EDIT:
MainScreensaver.cs
Random randGen = new Random();
public MainScreensaver(Rectangle bounds)
{
InitializeComponent();
this.Bounds = Bounds;
}
private void timer1_Tick(object sender, EventArgs e)
{
Rectangle screen = Screen.PrimaryScreen.Bounds;
Point position = new Point(randGen.Next(0,screen.Width-this.Width)+screen.Left,randGen.Next(0,screen.Height-this.Height)+screen.Top);
this.Location = position;
}
private void MainScreensaver_Load(object sender, EventArgs e)
{
Cursor.Hide();
TopMost = true;
}
private Point mouseLocation;
private void MainScreensaver_MouseMove(object sender, MouseEventArgs e)
{
if (!mouseLocation.IsEmpty)
{
// Terminate if mouse is moved a significant distance
if (Math.Abs(mouseLocation.X - e.X) > 5 ||
Math.Abs(mouseLocation.Y - e.Y) > 5)
Application.Exit();
}
// Update current mouse location
mouseLocation = e.Location;
}
private void MainScreensaver_KeyPress(object sender, KeyPressEventArgs e)
{
Application.Exit();
}
private void MainScreensaver_Deactive(object sender, EventArgs e)
{
Application.Exit();
}
private void MainScreensaver_MouseClick(object sender, MouseEventArgs e)
{
Application.Exit();
}
Excerpt from MainScreensaver.Designer.cs InitialiseComponent()
this.MouseClick += new System.Windows.Forms.MouseEventHandler(this.MainScreensaver_MouseClick);
this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.MainScreensaver_MouseMove);
This isn't an answer to you question, but I'm leaving this answer in case anyone else stumbles upon this question while trying to debug this same issue (which is how I got here)
In my case, I had a class that was derived from Form.
I was also using TransparencyKey.
Some things I noticed
The events will not fire on the transparent parts of the form.
The events will not fire if the mouse cursor is over another control on the form.
The events will not fire if you override WndProc and set the result of a WM_NCHITTEST message. Windows doesn't even send out the corresponding mouse messages that would cause the .NET events.
My Solution
In my constructor, I had forgotten to call InitializeComponent().
Which was where the event handlers were being bound to my controls.
Events were not firing because the handlers were not being bound.
Are you sure that your form has focus? If your form does not have focus, the mouse events will not be fired.
I have a program that is essentially like a paint application. However, my program has some flickering issues. I have the following line in my code (which should get rid of flickering - but doesn't):
this.SetStyle(ControlStyles.AllPaintingInWmPaint
| ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);
my code(minus the super and sub classes for the shapes is as follows:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Paint
{
public partial class Paint : Form
{
private Point startPoint;
private Point endPoint;
private Rectangle rect = new Rectangle();
private Int32 brushThickness = 0;
private Boolean drawSPaint = false;
private List<Shapes> listOfShapes = new List<Shapes>();
private Color currentColor;
private Color currentBoarderColor;
private Boolean IsShapeRectangle = false;
private Boolean IsShapeCircle = false;
private Boolean IsShapeLine = false;
public SPaint()
{
InitializeComponent();
this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);
currentColor = Color.Red;
currentBoarderColor = Color.DodgerBlue;
IsShapeRectangle = true;
}
private void panelArea_Paint(object sender, PaintEventArgs e)
{
Graphics g = panelArea.CreateGraphics();
if (drawSPaint == true)
{
Pen p = new Pen(Color.Blue);
p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
if (IsShapeRectangle == true)
{
g.DrawRectangle(p, rect);
}
else if (IsShapeCircle == true)
{
g.DrawEllipse(p, rect);
}
else if (IsShapeLine == true)
{
g.DrawLine(p, startPoint, endPoint);
}
}
foreach (Shapes shape in listOfShapes)
{
shape.Draw(g);
}
}
private void panelArea_MouseDown(object sender, MouseEventArgs e)
{
startPoint.X = e.X;
startPoint.Y = e.Y;
drawSPaint = true;
}
private void panelArea_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
if (e.X > startPoint.X)
{
rect.X = startPoint.X;
rect.Width = e.X - startPoint.X;
}
else
{
rect.X = e.X;
rect.Width = startPoint.X - e.X;
}
if (e.Y > startPoint.Y)
{
rect.Y = startPoint.Y;
rect.Height = e.Y - startPoint.Y;
}
else
{
rect.Y = e.Y;
rect.Height = startPoint.Y - e.Y;
}
panelArea.Invalidate();
}
}
private void panelArea_MouseUp(object sender, MouseEventArgs e)
{
endPoint.X = e.X;
endPoint.Y = e.Y;
drawSPaint = false;
if (rect.Width > 0 && rect.Height > 0)
{
if (IsShapeRectangle == true)
{
listOfShapes.Add(new TheRectangles(rect, currentColor, currentBoarderColor, brushThickness));
}
else if (IsShapeCircle == true)
{
listOfShapes.Add(new TheCircles(rect, currentColor, currentBoarderColor, brushThickness));
}
else if (IsShapeLine == true)
{
listOfShapes.Add(new TheLines(startPoint, endPoint, currentColor, currentBoarderColor, brushThickness));
}
panelArea.Invalidate();
}
}
private void rectangleToolStripMenuItem_Click(object sender, EventArgs e)
{
IsShapeRectangle = true;
IsShapeCircle = false;
IsShapeLine = false;
}
private void ellipseToolStripMenuItem_Click(object sender, EventArgs e)
{
IsShapeRectangle = false;
IsShapeCircle = true;
IsShapeLine = false;
}
private void lineToolStripMenuItem_Click(object sender, EventArgs e)
{
IsShapeCircle = false;
IsShapeRectangle = false;
IsShapeLine = true;
}
private void ThicknessLevel0_Click(object sender, EventArgs e)
{
brushThickness = 0;
}
private void ThicknessLevel2_Click(object sender, EventArgs e)
{
brushThickness = 2;
}
private void ThicknessLevel4_Click(object sender, EventArgs e)
{
brushThickness = 4;
}
private void ThicknessLevel6_Click(object sender, EventArgs e)
{
brushThickness = 6;
}
private void ThicknessLevel8_Click(object sender, EventArgs e)
{
brushThickness = 8;
}
private void ThicknessLevel10_Click(object sender, EventArgs e)
{
brushThickness = 10;
}
private void ThicknessLevel12_Click(object sender, EventArgs e)
{
brushThickness = 12;
}
private void ThicknessLevel14_Click(object sender, EventArgs e)
{
brushThickness = 14;
}
private void FillColour_Click(object sender, EventArgs e)
{
ColorDialog fillColourDialog = new ColorDialog();
fillColourDialog.ShowDialog();
currentColor = fillColourDialog.Color;
panelArea.Invalidate();
}
private void button1_Click(object sender, EventArgs e)
{
ColorDialog fillColourDialog = new ColorDialog();
fillColourDialog.ShowDialog();
currentBoarderColor = fillColourDialog.Color;
panelArea.Invalidate();
}
}
}
How do i stop the flickering?
*UPDATE:*This code actually works great when i'm drawing directly on the form. However, when i try to draw on the panel, flickering becomes an issue
For a "cleaner solution" and in order to keep using the base Panel, you could simply use Reflection to implement the double buffering, by adding this code to the form that holds the panels in which you want to draw in
typeof(Panel).InvokeMember("DoubleBuffered",
BindingFlags.SetProperty | BindingFlags.Instance | BindingFlags.NonPublic,
null, DrawingPanel, new object[] { true });
Where "DrawingPanel" is the name of the panel that you want to do the double buffering.
I know quite a lot of time has passed since the question was asked, but this might help somebody in the future.
Finally solved the flickering. Since I was drawing on a panel instead of the form the line of code below will not solve the flickering:
this.SetStyle(
ControlStyles.AllPaintingInWmPaint |
ControlStyles.UserPaint |
ControlStyles.DoubleBuffer,
true);
SetStyle must be of type 'YourProject.YourProject' (or derived from it) hence, you have to create a class as such (so that you can use MyPanel which will be derived from SPaint.SPaint and hence allowing you to use doublebuffering directly for the panel - rather than the form):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using SPaint;
namespace YourProject
{
public class MyPanel : System.Windows.Forms.Panel
{
public MyPanel()
{
this.SetStyle(
System.Windows.Forms.ControlStyles.UserPaint |
System.Windows.Forms.ControlStyles.AllPaintingInWmPaint |
System.Windows.Forms.ControlStyles.OptimizedDoubleBuffer,
true);
}
}
}
After you've done this(although you should really never edit the designer code unless you truly know what you're doing) you'll have to edit the Form.Designer.cs. Inside this file you will find code that looks like this:
this.panelArea = new YourProject.MyPanel();
The above line needs to be changed to:
this.panelArea = new MyPanel();
After I completed these steps, my paint program no longer flickers.
For anyone else having the same issue, the problem is finally solved.
Enjoy!
Copy and paste this into your project
protected override CreateParams CreateParams
{
get
{
CreateParams handleParam = base.CreateParams;
handleParam.ExStyle |= 0x02000000; // WS_EX_COMPOSITED
return handleParam;
}
}
This enables double-buffering for all controls from the form level down, otherwise double buffering needs to be individually enabled for each one... you may want to fine tune double bufferring after this because blanketed double buffering may give unwanted side effects.
I have had the same problem. I was never able to 100% rid myself of the flicker (see point 2), but I used this
protected override void OnPaint(PaintEventArgs e) {}
as well as
this.DoubleBuffered = true;
The main issue for flickering is making sure you
paint things it the right order!
make sure your draw function is < about 1/60th of a second
winforms invokes the OnPaint method each time the form needs to be redrawn. There are many ways it can be devalidated, including moving a mouse cursor over the form can sometimes invoke a redraw event.
And important note about OnPaint, is you don't start from scratch each time, you instead start from where you were, if you flood fill the background color, you are likely going to get flickering.
Finally your gfx object. Inside OnPaint you will need to recreate the graphics object, but ONLY if the screen size has changed. recreating the object is very expensive, and it needs to be disposed before it is recreated (garbage collection doesn't 100% handle it correctly or so says documentation). I created a class variable
protected Graphics gfx = null;
and then used it locally in OnPaint like so, but this was because I needed to use the gfx object in other locations in my class. Otherwise DO NOT DO THIS. If you are only painting in OnPaint, then please use e.Graphics!!
// clean up old graphics object
gfx.Dispose();
// recreate graphics object (dont use e.Graphics, because we need to use it
// in other functions)
gfx = this.CreateGraphics();
Hope this helps.
Double buffering is not going to be of much help here I'm afraid. I ran into this a while ago and ended up adding a separate panel in a rather clumsy way but it worked for my application.
Make the original panel that you have ( panelArea ) a transparent area, and put it on top of a 2nd panel, which you call panelDraw for example. Make sure to have panelArea in front. I whipped this up and it got rid of the flickering, but left the shape that was being drawn smeared out so it's not a full solution either.
A transparent panel can be made by overriding some paint actions from the original panel:
public class ClearPanel : Panel
{
public ClearPanel(){}
protected override CreateParams CreateParams
{
get
{
CreateParams createParams = base.CreateParams;
createParams.ExStyle |= 0x00000020;
return createParams;
}
}
protected override void OnPaintBackground(PaintEventArgs e){}
}
The idea is to handle drawing the temporary shape during the MouseMove event of the 'panelArea' and ONLY repaint the 'panelDraw' on the MouseUp Event.
// Use the panelDraw paint event to draw shapes that are done
void panelDraw_Paint(object sender, PaintEventArgs e)
{
Graphics g = panelDraw.CreateGraphics();
foreach (Rectangle shape in listOfShapes)
{
shape.Draw(g);
}
}
// Use the panelArea_paint event to update the new shape-dragging...
private void panelArea_Paint(object sender, PaintEventArgs e)
{
Graphics g = panelArea.CreateGraphics();
if (drawSETPaint == true)
{
Pen p = new Pen(Color.Blue);
p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
if (IsShapeRectangle == true)
{
g.DrawRectangle(p, rect);
}
else if (IsShapeCircle == true)
{
g.DrawEllipse(p, rect);
}
else if (IsShapeLine == true)
{
g.DrawLine(p, startPoint, endPoint);
}
}
}
private void panelArea_MouseUp(object sender, MouseEventArgs e)
{
endPoint.X = e.X;
endPoint.Y = e.Y;
drawSETPaint = false;
if (rect.Width > 0 && rect.Height > 0)
{
if (IsShapeRectangle == true)
{
listOfShapes.Add(new TheRectangles(rect, currentColor, currentBoarderColor, brushThickness));
}
else if (IsShapeCircle == true)
{
listOfShapes.Add(new TheCircles(rect, currentColor, currentBoarderColor, brushThickness));
}
else if (IsShapeLine == true)
{
listOfShapes.Add(new TheLines(startPoint, endPoint, currentColor, currentBoarderColor, brushThickness));
}
panelArea.Invalidate();
}
panelDraw.Invalidate();
}
I know this is really old question but maybe someone will find it useful.
I'd like to make little enhancement to viper's answer.
You can make simple extension to Panel class and hide setting property through reflection.
public static class MyExtensions {
public static void SetDoubleBuffered(this Panel panel) {
typeof(Panel).InvokeMember(
"DoubleBuffered",
BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.SetProperty,
null,
panel,
new object[] { true });
}
}
If your Panel variable's name is myPanel you can just call
myPanel.SetDoubleBuffered();
and that's it. Code looks much cleaner.
I'd advise overriding OnPaintBackground and handling the background erase yourself. If you know you are painting the whole control you can just do nothing in OnPaintBackground (don't call the base method) and it will prevent the background colour being painted first
In this condition you have to enable double buffer .
Open current form and go to form properties and apply double buffer true;
or you can also write this code .
this.DoubleBuffered = true;
In form load.
if all of the above doesn't work you can always create your own double buffer
link to Microsofts tutorial: https://learn.microsoft.com/en-us/dotnet/framework/winforms/advanced/how-to-reduce-graphics-flicker-with-double-buffering-for-forms-and-controls
hopes it works for you
It's a bit of and old question, but just to be complete: There is yet another solution, that worked for me where the double-buffering did not.
As it turns out Microsoft offers the BufferedGraphics class as a solution. Nice thing about this class is that it enables you to copy one Graphics object to another, so except from setting up a temporary Graphics object and eventually copying it to the final destination, one can use pretty much the same code that one would have done when the flickering should not have been a problem:
private void Indicator_Paint(object sender, PaintEventArgs e)
{
Control pbIndicator = (Control)sender;
Rectangle targetRect = pbIndicator.ClientRectangle;
Image img = Bitmap.FromFile("bitmap.bmp");
BufferedGraphicsContext ctx = new BufferedGraphicsContext();
BufferedGraphics bg = ctx.Allocate(e.Graphics, targetRect);
// Do the graphic stuff
bg.Graphics.Clear(this.BackColor);
bg.Graphics.DrawImage(img, 0, 0);
// etcetera
bg.Render(e.Graphics);
bg.Dispose();
ctx.Dispose();
}
Downside of this solution that it might clutter your code. Furthermore I'm not sure whether it is a good idea to setup the context each time, or whether it would suffice to create one in advance and keep using that context.
For more information see https://learn.microsoft.com/en-us/dotnet/api/system.drawing.bufferedgraphicscontext?view=dotnet-plat-ext-3.1
here is the program of moving circle in .net, that doesn't flicker.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;
namespace CircleMove
{
/// <summary>
/// Description of MainForm.
/// </summary>
public partial class MainForm : Form
{
int x=0,y=0;
Thread t;
public MainForm()
{
//
// The InitializeComponent() call is required for Windows Forms designer support.
//
InitializeComponent();
//
// TODO: Add constructor code after the InitializeComponent() call.
//
}
void MainFormPaint(object sender, PaintEventArgs e)
{
Graphics g=e.Graphics;
Pen p=new Pen(Color.Orange);
Brush b=new SolidBrush(Color.Red);
// g.FillRectangle(b,0,0,100,100);
g.FillEllipse(b,x,y,100,100);
}
void MainFormLoad(object sender, EventArgs e)
{
t=new Thread( new ThreadStart(
()=>{
while(true)
{
Thread.Sleep(10);
x++;y++;
this.Invoke(new Action(
()=>{
this.Refresh();
this.Invalidate();
this.DoubleBuffered=true;
}
)
);
}
}
)
);
t.Start();
}
}
}
If memory is tight (so you don't want the memory cost of double-buffering), one possible way to REDUCE, though not eliminate, flicker, is to set background color to the dominant color in your current scene.
Why this helps: flicker is a momentary flash of the background color, which the OS draws before drawing child controls or your custom drawing code. If that flash is a color that is closer to the final color to be displayed, it will be less noticeable.
If you are not sure what color to start with, start with 50% gray, because this is an average of black and white, so will be closer to most colors in your scene.
myFormOrControl.BackColor = Color.Gray;
Try to insert drawing logic in current form's
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
}
method. In this case you should use parameter e to get Graphics object. Use e.Graphics property. Then you should invoke Invalidate() method for this form whenever form must be redrawn.
PS: DoubleBuffered must be set to true.
Drawing onto a Label instead of a Panel, solved the problem for me.
No need to use DoubleBuffering or anything either.
You can remove the text from the label, set AutoSize to false, then Dock it or set the Size and use it as for the Panel.
Best wishes,
Quite late into the game... but for me WS_EX_COMPOSITED worked fine for a while and after some time of application start, layout started behaving very weird. I use TabControl and some TabPages on addition/removal started displaying titles of its siblings, so be careful with using it. Without WS_EX_COMPOSITED all worked fine, but I still had the flickering issue on new TabPage add.
None solution here really worked for me so I started looking at my code. I have a functionality where I create RichTextBox, then this RichTextBox is added to newly created TabPage and finally TabPage is added to TabControl. I decided to change order of that action - firstly I create TabPage, then add it to TabControl, and when TabPage is already added to TabControl, I add RichTextBox to it. When I did that, no more flickering and all works perfectly without any 'hacks'.
The moral of the story is that if nothing really works for you, try to (if possible and applicable in your case) play around with order in which you add controls.
Can you try using a timer and boolean to check if mouse is down, and paint in that spot, using a variable again check if user has moved his mouse, if moved paint that spot too etc.
Or just check if mouse down(via boolean that sets true when mouse is down) using a timer and paint it considering you are probably trying to just paint one pixel, not like you have shadow etc. Instead of using actual mousedown. So you check every 1 second instead of 0.0001 and it wont flicker. Or vice-versa, try it with your own times.
just do this.Refresh() when shown the form.