OnPaint Paint Issue - c#

I have created a custom checkBox to increase the height of the rectangle of the checkbox. I have override the OnPaint method as given below. When I make the control transparent, background becomes white, instead of transparent. What could be the issue?
protected override void OnPaint(PaintEventArgs pevent)
{
base.OnPaint(pevent);
int h = this.Height;
if (BackColor == Color.Transparent)
{
pevent.Graphics.Clear(this.Parent.BackColor);
}
else
{
pevent.Graphics.Clear(BackColor);
}
Rectangle rc = new Rectangle(new Point(0, 0), new Size(h, h));
ControlPaint.DrawCheckBox(pevent.Graphics, rc,
this.Checked ? ButtonState.Checked : ButtonState.Normal);
SizeF stringMeasure = pevent.Graphics.MeasureString(Text, Font);
int topOffset = (int)(ClientRectangle.Height - stringMeasure.Height) / 2;
pevent.Graphics.DrawString(Text, Font, new SolidBrush(ForeColor), this.Height, topOffset);
}

I am not sure if you derived your checkbox from the given class CheckBox or you derived it from Control. If you derived from control, you should add in the constructor the following line:
public CustomChecBox()
: base()
{
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
}
Note, that there is also a function called OnPaintBackground(...) which you can override, but you should not need to to this.
In your OnPaint()-function, you should replace
if (BackColor == Color.Transparent)
{
pevent.Graphics.Clear(this.Parent.BackColor);
}
else
{
pevent.Graphics.Clear(BackColor);
}
with
pevent.Graphics.Clear(BackColor);
or
pevent.Graphics.FillRectangle(new SolidBrush(this.BackColor), this.ClientRectangle);
But this is, what happens in OnPaintBackground(...). If you set the BackColor to transparent and you added the SetStyle-Methid in the contructor, then your control should be really transparent. I hope this helps.

Related

Draw Border around ListBox

How would I go about drawing a border with a specified width and color around a listbox?
Can this be done without overriding the OnPaint method?
Following Neutone's suggestion, here is a handy function to add and remove a Panel-based border around any control, even if it is nested..
Simply pass in the Color and size you want, and if you want a BorderStyle. To remove it again pass in Color.Transparent!
void setBorder(Control ctl, Color col, int width, BorderStyle style)
{
if (col == Color.Transparent)
{
Panel pan = ctl.Parent as Panel;
if (pan == null) { throw new Exception("control not in border panel!");}
ctl.Location = new Point(pan.Left + width, pan.Top + width);
ctl.Parent = pan.Parent;
pan.Dispose();
}
else
{
Panel pan = new Panel();
pan.BorderStyle = style;
pan.Size = new Size(ctl.Width + width * 2, ctl.Height + width * 2);
pan.Location = new Point(ctl.Left - width, ctl.Top - width);
pan.BackColor = col;
pan.Parent = ctl.Parent;
ctl.Parent = pan;
ctl.Location = new Point(width, width);
}
}
You can place a list box within a panel and have the panel serve as a border. The panel backcolor can be used to create a colored border. This doesn't require much code. Having a colored border around a form component can be an effective way of conveying status.
The problem with the ListBox control is that it does not raise the OnPaint method so you can not use it to draw a border around the control.
There are two methods to paint a custom border around the ListBox:
Use SetStyle(ControlStyles.UserPaint, True) in the constructor, then you can use the OnPaint method to draw the border.
Override WndProc method that handles operating system messages identified in the Message structure.
I used the last method to paint a custom border around the control, this will eliminate the need to use a Panel to provide a custom border for the ListBox.
public partial class MyListBox : ListBox
{
public MyListBox()
{
// SetStyle(ControlStyles.UserPaint, True)
BorderStyle = BorderStyle.None;
}
protected override void WndProc(ref Message m)
{
base.WndProc(m);
var switchExpr = m.Msg;
switch (switchExpr)
{
case 0xF:
{
Graphics g = this.CreateGraphics;
g.SmoothingMode = Drawing2D.SmoothingMode.Default;
int borderWidth = 4;
Rectangle rect = ClientRectangle;
using (var p = new Pen(Color.Red, borderWidth) { Alignment = Drawing2D.PenAlignment.Center })
{
g.DrawRectangle(p, rect);
}
break;
}
default:
{
break;
}
}
}
}

Remove extra padding in custom button control

I need some help on removing extra padding around the edges of a custom button control in C#.
The width of this button is 68, and I'd like to keep it that way. If I change it to 70, then the text fits all on one line.
Button control code:
public partial class FlatButton : System.Windows.Forms.Button
{
public FlatButton() : base()
{
FlatAppearance.BorderSize = 0;
FlatStyle = System.Windows.Forms.FlatStyle.Flat;
BackColor = Color.FromArgb(58, 58, 58);
ForeColor = Color.White;
}
protected override bool ShowFocusCues
{
get
{
return false;
}
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
Pen pen = new Pen(FlatAppearance.BorderColor, 1);
Rectangle rectangle = new Rectangle(0, 0, Size.Width, Size.Height);
e.Graphics.DrawRectangle(pen, rectangle);
}
public override void NotifyDefault(bool value)
{
}
}
Any ideas on how to remove the extra padding and allow the text to fit all in one line?

Inherited GroupBox has OnPaint jitters

I've been searching all morning and unfortunately I'm not sure what the techincal term is for this issue, so I'm unable to find a resolution.
When I derive from a GroupBox and override the onPaint function the groupboxes are redrawing themselves over-top the previous groupboxes. The child controls paint correctly, just the groupbox is affected..
class ExtendedComponents
{
public partial class extendedGroupBox : GroupBox
{
private Color borderColor;
public extendedGroupBox()
{
this.SetStyle(ControlStyles.DoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.ContainerControl, true);
this.borderColor = Color.Black;
}
[NotifyParentProperty(true)]
public Color BorderColor
{
get { return this.borderColor; }
set { this.borderColor = value; Invalidate(); }
}
protected override void OnPaint(PaintEventArgs e)
{
Size tSize = TextRenderer.MeasureText(this.Text, this.Font);
Rectangle borderRect = e.ClipRectangle;
borderRect.Y += tSize.Height / 2;
borderRect.Height -= tSize.Height / 2;
ControlPaint.DrawBorder(e.Graphics, borderRect, this.borderColor, ButtonBorderStyle.Dotted);
Rectangle textRect = e.ClipRectangle;
textRect.X += 6;
textRect.Width = tSize.Width + 5;
textRect.Height = tSize.Height;
e.Graphics.FillRectangle(new SolidBrush(this.BackColor), textRect);
e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), textRect);
}
}
}
Any help would be much appreciated!
The easy answer is to not use the GroupBox control-- it's inherently flicky.
Try using a Panel control instead with your DoubleBuffer SetStyles, etc.
For your current implementation, don't use the e.ClipRectangle:
//Rectangle borderRect = e.ClipRectangle;
Rectangle borderRect = this.ClientRectangle;
//Rectangle textRect = e.ClipRectangle;
Rectangle textRect = this.ClientRectangle;
Another thing to note is that you should override OnPaintBackground to avoid flicker. There you either do nothing or draw the control fore color.

Customize ToolStripMenuItem

I want to customize ToolStripMenuItem by overriding OnPaint function. This is a MyToolStripMenuItem:
public class MyToolStripMenuItem : ToolStripMenuItem
{
public MyToolStripMenuItem()
:base()
{
}
public MyToolStripMenuItem(string t)
:base(t)
{
}
protected override void OnPaint(PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = this.Bounds;
g.FillRectangle(Brushes.Blue, r);
g.DrawString(this.Text, this.Font, Brushes.Red, r);
}
}
In my code, I will fill a blue color in item's bound. Now, I will create a list of items on menustrip:
MyToolStripMenuItem1
|___MyToolStripMenuItem2
|___MyToolStripMenuItem3
I don't know why MyToolStripMenuItem3 don't have a blue background.
This is my source code:
http://www.mediafire.com/?2qhmjzzfzzn
Please help me. Thanks.
It's not the way it is done with a ToolStripMenuItem. You give the MenuStrip a custom renderer. For example:
For example:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
menuStrip1.Renderer = new MyRenderer();
}
private class MyRenderer : ToolStripProfessionalRenderer {
protected override void OnRenderMenuItemBackground(ToolStripItemRenderEventArgs e) {
if (!e.Item.Selected) base.OnRenderMenuItemBackground(e);
else {
Rectangle rc = new Rectangle(Point.Empty, e.Item.Size);
e.Graphics.FillRectangle(Brushes.Beige, rc);
e.Graphics.DrawRectangle(Pens.Black, 1, 0, rc.Width - 2, rc.Height - 1);
}
}
}
}
The problem with using OnRenderMenuItemBackground() is that it applies to the whole menu and not just the one ToolStripMenuItem.
The error in the code lies in Rectangle r = this.Bounds; which produces the wrong area. Change this to Rectangle r = e.ClipRectangle and it should work ok. (For some reason the Bounds has the wrong Y component).

C#: Overriding OnPaint on ProgressBar not working?

Was thinking it should be pretty easy to create a ProgressBar that drew some text upon itself. However, I am not quite sure what is happening here...
I added the following two overrides:
protected override void OnPaintBackground(PaintEventArgs pevent)
{
base.OnPaintBackground(pevent);
var flags = TextFormatFlags.VerticalCenter | TextFormatFlags.HorizontalCenter | TextFormatFlags.SingleLine | TextFormatFlags.WordEllipsis;
TextRenderer.DrawText(pevent.Graphics, "Hello", Font, Bounds, Color.Black, flags);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
var flags = TextFormatFlags.VerticalCenter | TextFormatFlags.HorizontalCenter | TextFormatFlags.SingleLine | TextFormatFlags.WordEllipsis;
TextRenderer.DrawText(e.Graphics, "Hello", Font, Bounds, Color.Black, flags);
}
However, I get no text, and the methods doesn't even seem to be called. What is going on here?
Update: Thanks to the two answers so far, I have gotten it to actually call the OnPaint by using SetStyle(ControlStyles.UserPaint, true), and I have gotten it to draw the text in the right place by sending in new Rectangle(0, 0, Width, Height) instead of Bounds.
I do get text now, but the ProgressBar is gone... and the point was kind of to have the text on top of the ProgressBar. Any idea how I can solve this?
You could override WndProc and catch the WmPaint message.
The example below paints the Text property of the progressbar in its center.
public class StatusProgressBar : ProgressBar
{
const int WmPaint = 15;
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
switch (m.Msg)
{
case WmPaint:
using (var graphics = Graphics.FromHwnd(Handle))
{
var textSize = graphics.MeasureString(Text, Font);
using(var textBrush = new SolidBrush(ForeColor))
graphics.DrawString(Text, Font, textBrush, (Width / 2) - (textSize.Width / 2), (Height / 2) - (textSize.Height / 2));
}
break;
}
}
}
I needed to do this myself and I thought that I would post a simplified example of my solution since I could not find any examples. It is actually pretty simple if you use the ProgressBarRenderer class:
class MyProgressBar : ProgressBar
{
public MyProgressBar()
{
this.SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);
}
protected override void OnPaint(PaintEventArgs e)
{
Rectangle rect = this.ClientRectangle;
Graphics g = e.Graphics;
ProgressBarRenderer.DrawHorizontalBar( g, rect );
rect.Inflate(-3, -3);
if ( this.Value > 0 )
{
Rectangle clip = new Rectangle( rect.X, rect.Y, ( int )Math.Round( ( ( float )this.Value / this.Maximum ) * rect.Width ), rect.Height );
ProgressBarRenderer.DrawHorizontalChunks(g, clip);
}
// assumes this.Maximum == 100
string text = this.Value.ToString( ) + '%';
using ( Font f = new Font( FontFamily.GenericMonospace, 10 ) )
{
SizeF strLen = g.MeasureString( text, f );
Point location = new Point( ( int )( ( rect.Width / 2 ) - ( strLen.Width / 2 ) ), ( int )( ( rect.Height / 2 ) - ( strLen.Height / 2 ) ) );
g.DrawString( text, f, Brushes.Black, location );
}
}
}
Your problem is that you're passing in Bounds as your Rectangle parameter. Bounds contains the Height and Width of your control, which is what you want, but it also contains the Top and Left properties of your control, relative to the parent form, so your "Hello" is being offset on the control by however much your control is offset on its parent form.
Replace Bounds with new Rectangle(0, 0, this.Width, this.Height) and you should see your "Hello".
It seems that if you call 'SetStyle(ControlStyles.UserPaint, true)' the standard OnPaint method implemented for ProgressBar could not be invoked (using base.OnPaint(e) does not work at all). The strangest thing is that even if you actually create a UserControl, and try to draw draw some text upon the progress bar... it doesn't seem to work too... Of course you may place a Label on top of it... but I suppose it is not actually what you wanted to achieve.
Ok, it seems that I have managed to solve this problem. It is although a little complicated. First you need to create a transparent Label control. Code below:
public class TransparentLabel : System.Windows.Forms.Label
{
public TransparentLabel()
{
this.SetStyle(ControlStyles.Opaque, true);
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
}
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20;
return cp;
}
}
}
Second thing is to create UserControl, place a ProgressBar on it (Dock=Fill) - this will be the control that we will use instead of standard ProgressBar. Code:
public partial class UserControl2 : UserControl
{
public UserControl2()
{
InitializeComponent();
}
protected override void OnPaint(PaintEventArgs e)
{
this.progressBar1.SendToBack();
this.transparentLabel1.BringToFront();
this.transparentLabel1.Text = this.progressBar1.Value.ToString();
this.transparentLabel1.Invalidate();
}
public int Value
{
get { return this.progressBar1.Value; }
set
{
this.progressBar1.Value = value;
}
}
}
The strange thing with ProgressBar is that it 'overdraws' the controls that are being placed upon it, so it is needed to send progressbar to back, and bring the label control to front. I haven't found more elegant solution at the moment.
This works, the label is being displayed on the progressbar, the background of the label control is transparent, so I think it looks like you wanted it to look :)
I may share my sample code if you wish...
Oh, btw. this strange behaviour of ProgressBar control that I have mentioned, is responsible for that it is not possible to use Graphics object to draw anything on a control that derives from ProgressBar. The text (or whatever you draw using Graphics object) is actually being drawn but... behind the ProgressBar control (if you take a closer look, you may see this user drawn things flickering when the Value of the ProgressBar changes and it need to repaint itself).
Here's another solution along with other people's suggestions. I subclassed the progressbar control to make this work. I mixed and matched codes from various places for this. The paint event could be cleaner, but that's for you to do ;)
public class LabeledProgressBar: ProgressBar
{
private string labelText;
public string LabelText
{
get { return labelText; }
set { labelText = value; }
}
public LabeledProgressBar() : base()
{
this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
this.Paint += OnLabelPaint;
}
public void OnLabelPaint(object sender, PaintEventArgs e)
{
using(Graphics gr = this.CreateGraphics())
{
string str = LabelText + string.Format(": {0}%", this.Value);
LinearGradientBrush brBG = new LinearGradientBrush(e.ClipRectangle,
Color.GreenYellow, Color.Green, LinearGradientMode.Horizontal);
e.Graphics.FillRectangle(brBG, e.ClipRectangle.X, e.ClipRectangle.Y,
e.ClipRectangle.Width * this.Value / this.Maximum, e.ClipRectangle.Height);
e.Graphics.DrawString(str, SystemFonts.DefaultFont,Brushes.Black,
new PointF(this.Width / 2 - (gr.MeasureString(str, SystemFonts.DefaultFont).Width / 2.0F),
this.Height / 2 - (gr.MeasureString(str, SystemFonts.DefaultFont).Height / 2.0F)));
}
}
}

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