Better way to refresh a custom control - c#

I'm learning how to write custom control and manage and raise events.
I'have create a pointless custom control, a line you can add on main and decide size and color. I've made also an event to replace OnClick (I'm just learning) and I've called it MyClick. Here's the code
public class EditedLine : UserControl
{
public delegate void LineClickEventHandler(object sender, EditedLineClickEventArgs e);
[Description("Occurs when control is clicked")]
public event LineClickEventHandler MyClick;
private Color _color;
private float _size;
public EditedLine()
{
_color = Color.Black;
_size = 3;
}
public EditedLine(Color color, float size)
{
_color = color;
_size = size;
}
public Color LineColor
{
get { return _color; }
set { _color = value; }
}
public float LineSize
{
get { return _size; }
set { _size = value; }
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawLine(new Pen(_color, _size), new Point(0, 0), new Point(this.Size.Width, 0));
}
protected override void OnClick(EventArgs e)
{
base.OnClick(e);
OnLineClick(new EditedLineClickEventArgs());
}
protected virtual void OnLineClick(EditedLineClickEventArgs e)
{
if (MyClick != null)
{
MyClick(this, e);
}
}
}
}
luckly everythings is working. I can see my control in the control toolbox and I can add to my project, even the event is working.
But, if inside MyClick i try to change the color of the Line, nothing happens.
I have to use this Proprieties intead of the ones before:
public Color LineColor
{
get { return _color; }
set { _color = value; this.Refresh(); }
}
public float LineSize
{
get { return _size; }
set { _size = value; this.Refresh(); }
}
So I'm asking myself if there is a better way to refresh the control. If I'm redrawing a single line is easy to be done, but if it is a more complex control? I thought to do a 'Redraw' private method but I don't know how to access the 'Graphic' object of the EditedLine istance. Is 'INotifyPropertyChanged' useful? But the 'Graphic' still remains my biggest problem

If you are talking about more complex control, then consider to change Refresh to Invalidate to invalidate specific regions of your UserControl.
To get Graphics object just call CreateGraphics method.

Related

c# Add transparent label on web eye web cam control

I have been working on an Iron Man hud. I am using WebEye to access the web cam... now i have to add label over the web cam control but the label is not transparent
I have tried every control but cant use the transparency function..
Here's my code
foreach (WebCameraId camera in webCameraControl1.GetVideoCaptureDevices())
{
comboBox1.Items.Add(new ComboBoxItem(camera));
}
if (comboBox1.Items.Count > 0)
{
comboBox1.SelectedItem = comboBox1.Items[0];
}
ComboBoxItem i = (ComboBoxItem)comboBox1.SelectedItem;
try
{
webCameraControl1.StartCapture(i.Id);
}
finally
{
//Do something if u want to
}
please help!!
Actually, creating a transparent label will not help over video. If your webCameraControl is not a sealed class, you can inherit it to add the text directly on it's surface, like I did with this picture box:
public partial class LabledPictureBox : PictureBox
{
public LabledPictureBox()
{
InitializeComponent();
}
#region properties
// I needed to override these properties to make them Browsable....
[Browsable(true)]
public override string Text
{
get
{
return base.Text;
}
set
{
base.Text = value;
}
}
[Browsable(true)]
public override Font Font
{
get
{
return base.Font;
}
set
{
base.Font = value;
}
}
[Browsable(true)]
public override Color ForeColor
{
get
{
return base.ForeColor;
}
set
{
base.ForeColor = value;
}
}
#endregion properties
protected override void OnPaint(PaintEventArgs pe)
{
base.OnPaint(pe);
// This is actually the only code line that's needed to add the text to the picture box
TextRenderer.DrawText(pe.Graphics, this.Text, this.Font, pe.ClipRectangle, this.ForeColor);
}
}
The most important thing here is the line right after base.OnPaint - That line actually paints the text directly over the surface of the already painted control.

Unable to register click event from composite control to parent form

What I am attempting to do is create a complex control that has a picture box, track slider and numeric up down controls. In the parent form, when the user clicks on an image, then this composite control appears and the background color is then sent to it and the image in the control is then set with that background color. Then if the user clicks on the image on the composite control, the parent form is then notified of the click event and then subsequently removes that specific composite control from the parent form.
Composite Control code
using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
namespace ctlClusterControlLib
{
public partial class UserControl1 : UserControl
{
private Color colImageBackground;
private int intThreadCount;
private PictureBox pictureBoxControl; // Compiler informs me that this is never assigned to and will always have its default value null.
private TrackBar trackBar; // Compiler informs me that this is never assigned to and will always have its default value null.
private NumericUpDown numericUpDown; // Compiler informs me that this is never assigned to and will always have its default value null.
private string strImageToolTip1;
private string strImageToolTip2;
private static object EventSubmitKey = new object();
public UserControl1()
{
InitializeComponent();
}
public Color ImageBackground
{
get { return colImageBackground; }
set { colImageBackground = value; Invalidate(); }
}
public int ThreadCount
{
get { return intThreadCount; }
set { intThreadCount = value; }
}
[
Category("Action"),
Description("Raised when the user clicks on the image.")
]
public event EventHandler PictureClick
{
add { Events.AddHandler(EventSubmitKey, value); }
remove { Events.RemoveHandler(EventSubmitKey, value); }
}
public event EventHandler TrackBarScroll
{
add { trackBar.Scroll += value; }
remove { trackBar.Scroll -= value; }
}
public event EventHandler numericUpDownChange
{
add { numericUpDown.ValueChanged += value; }
remove { numericUpDown.ValueChanged -= value; }
}
public string ImageToolTip1
{
get { return strImageToolTip1; }
set { strImageToolTip1 = value; }
}
public string ImageToolTip2
{
get { return strImageToolTip2; }
set { strImageToolTip2 = value; }
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
numericUpDown1.Value = trackBar1.Value;
}
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
trackBar1.Value = Convert.ToInt32(numericUpDown1.Value);
}
protected override void OnPaint(PaintEventArgs pe)
{
base.OnPaint(pe);
Color c = Color.FromArgb(0xFF, colImageBackground);
pictureBox1.BackColor = c;
}
}
}
Parent Form CS relevant section:
private void newPictureBox_Click(object sender, EventArgs e)
{
UserControl1 _UserControl = new UserControl1();
PictureBox _PictureBox = (PictureBox)sender;
string _NewControlClusterName = "_New" + _PictureBox.Name;
_UserControl.Name = _NewControlClusterName;
_UserControl.ThreadCount = 16;
_UserControl.ImageBackground = _PictureBox.BackColor;
_UserControl.Dock = DockStyle.Top;
_UserControl.PictureClick += new EventHandler(ClusterControl_Click);
//_UserControl.TrackBarScroll += new EventHandler(GetTartanCode);
panel3.Controls.Add(_UserControl);
panel3.Controls.SetChildIndex(_UserControl, 0);
}
And I am having intermittent issues with raising the click event to the parent form using this control.
I have tried everything I can find in Google and Stack Overflow with no joy. My questions are this:
Am I even in the right ballpark?
Is this something that needs to be coded in the parent form cs file?
Is this something that needs to be reconfigured in the composite control cs file?
Is this something that needs to be configured in both files?
I believe I have a solution.
What I was not doing was directly assigning the request to the control I wanted to register the event for. Instead I was assigning it to a new control and therefore nothing would happen.
public event EventHandler PictureClick
{
add { pictureBox1.Click += value; }
remove { pictureBox1.Click -= value; }
}
And so far, It works every time.

Alternate background color of rows in a CheckedListBox?

I need to alternate the color of the items in my CheckedListBox but "alternatingColors" is not a property of CheckedListBox.
How do I go about making the item's colors alternate?
The OnDrawItem event is inaccessible by default, but if you derive a new control based on CheckedListBox, then you can override the base event.
public class MyCheckedListBox : CheckedListBox
{
private SolidBrush primaryColor = new SolidBrush(Color.White);
private SolidBrush alternateColor = new SolidBrush(Color.LightGreen);
[Browsable(true)]
public Color PrimaryColor
{
get { return primaryColor.Color; }
set { primaryColor.Color = value; }
}
[Browsable(true)]
public Color AlternateColor
{
get { return alternateColor.Color; }
set { alternateColor.Color = value; }
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
base.OnDrawItem(e);
if (Items.Count <= 0)
return;
var contentRect = e.Bounds;
contentRect.X = 16;
e.Graphics.FillRectangle(e.Index%2 == 0 ? primaryColor : alternateColor, contentRect);
e.Graphics.DrawString(Convert.ToString(Items[e.Index]), e.Font, Brushes.Black, contentRect);
}
}
It'll alternate between white and green by default. Make adjustments in the Properties panel at design time, or during runtime.
I don't think this is even possible. You may want to consider using a different control for what you need. A DataGridView might be able to work for you better.

How to use the Control.Update method in a custom control

I'm going to post my code first since it is short and easy to understand, then i'll ask my question.
public class BatteryLabel : Control
{
private Color _captionColor = SystemColors.Control;
private Color _textColor = SystemColors.Info;
private Color _failColor = Color.Red;
private Color _passColor = Color.Green;
private string _caption;
string text2;
string text3;
bool battery1Fail = false;
bool battery2Fail = false;
bool battery3Fail = false;
public BatteryLabel()
{
}
public Color BackgroundTextColor
{
get{ return _textColor;}
set{_textColor = value; Invalidate();}
}
public string Caption
{
get
{
return _caption;
}
set
{
_caption = value;
Invalidate();
}
}
public override string Text
{
get
{
return base.Text;
}
set
{
base.Text = value;
Invalidate();
}
}
public string Text2
{
get { return text2; }
set { text2 = value; Invalidate(); }
}
public string Text3
{
get { return text3; }
set { text3 = value; Invalidate(); }
}
public bool Battery1Fail
{
get { return battery1Fail; }
set { battery1Fail = value; Invalidate(); }
}
public bool Battery2Fail
{
get { return battery2Fail; }
set { battery2Fail = value; Invalidate(); }
}
public bool Battery3Fail
{
get { return battery3Fail; }
set { battery3Fail = value; Invalidate(); }
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawRectangle(Pens.Black, 0,0, Width-1, Height-1);
var x1 = 50;
var x2 = 98;
var x3 = 146;
var color1 = battery1Fail?_failColor:BackgroundTextColor;
var color2 = battery2Fail?_failColor:BackgroundTextColor;
var color3 = battery3Fail?_failColor:BackgroundTextColor;
e.Graphics.FillRectangle(new SolidBrush(color1),x1+1, 1, 47, Height-2);
e.Graphics.FillRectangle(new SolidBrush(color2),x2+1, 1, 47, Height-2);
e.Graphics.FillRectangle(new SolidBrush(color3),x3+1, 1, 47, Height-2);
e.Graphics.DrawLine(Pens.Black, x1,0, x1, Height-1);
e.Graphics.DrawLine(Pens.Black, x2,0, x2, Height-1);
e.Graphics.DrawLine(Pens.Black, x3,0, x3, Height-1);
var BoldFont = new Font(this.Font, FontStyle.Bold);
e.Graphics.DrawString(Caption, BoldFont, new SolidBrush(ForeColor), 0,0);
e.Graphics.DrawString(Text, this.Font, new SolidBrush(ForeColor), x1,0);
e.Graphics.DrawString(Text2, this.Font, new SolidBrush(ForeColor), x2,0);
e.Graphics.DrawString(Text3, this.Font, new SolidBrush(ForeColor), x3,0);
}
}
The controls size is meant to be 195,14 just in case you decide to try to use it. I have 8 of these in a panel that is 200,200 running on a 1.6Ghz atom processor. It is used to display values from up to 3 batteries on a computer. The labels get refreshed every 500ms. As you may have gathered there is a little bit of flickering, but it is tolerable. I'd just like to have even less if possible. So I started looking into using Update, and moving some of my code around such as the background bit I thought maybe i should move that to OnPaintBackground(), but in a test frame that i made up the Update method does not change anything, and when I use Invalidate method it runs both OnPaintBackground and OnPaint. Here is what I tried in that case.
public class InformationLabel : Control
{
Random r = new Random();
protected override void OnPaintBackground(PaintEventArgs e)
{
base.OnPaintBackground(e);
Color randomCOlor = Color.FromArgb(r.Next());
e.Graphics.FillRectangle(new SolidBrush(randomCOlor),0,0, Width-1, Height-1);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
Color randomCOlor = Color.FromArgb(r.Next());
e.Graphics.FillPie(new SolidBrush(randomCOlor),15,15,15,15, 0.0f, 120.0f);
}
}
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
}
void Button1Click(object sender, EventArgs e)
{
informationLabel1.Update();
}
void Button2Click(object sender, EventArgs e)
{
informationLabel1.Invalidate();
}
}
I made that one usercontrol about 300,300 so i could be sure of what i was seeing. I forgot to mention that in the battery control in my 500ms timer i just renew text, text2, and text3. I'm thinking that if the value of that text is out of spec that I'll set the battery fail flag and then invalidate.. but i'm not sure. So how should I go about updating only the text???
You can get rid of the flickering by adding this line in your constructor:
SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.UserPaint | ControlStyles.Opaque | ControlStyles.AllPaintingInWmPaint, true);
Now paint both background and everything else in your paint handler.
Optimizing can be done by passing a Rectangle to Invalidate for only the area that needs repainting. Then in your OnPaint override you use e.ClipRectangle to figure out what to draw. This is probably not necessary for such a simple drawing.
I believe you are looking in the wrong place to eliminate flicker. I can use your BatteryLabel to get flickerless updating of the text with basically a single line. Change your constructor to look like this:
public BatteryLabel()
{
this.SetStyle(ControlStyles.OptimizedDoubleBuffer,true);
}
This tells the control to double-buffer its graphics, which makes the flicker go away.
To test with a 100ms refresh interval:
Timer t;
public Form1()
{
InitializeComponent();
t = new Timer();
t.Interval = 100;
t.Tick += new EventHandler(t_Tick);
t.Start();
}
void t_Tick(object sender, EventArgs e)
{
string ticks = DateTime.Now.Ticks.ToString();
string ticks1 = ticks.Substring(ticks.Length-4),
ticks2 = ticks.Substring(ticks.Length - 5,4),
ticks3 = ticks.Substring(ticks.Length - 6,4);
batteryLabel1.Text = ticks1;
batteryLabel1.Text2 = ticks2;
batteryLabel1.Text3 = ticks3;
batteryLabel1.Battery1Fail = ticks1.StartsWith("1");
batteryLabel1.Battery2Fail = ticks2.StartsWith("1");
batteryLabel1.Battery3Fail = ticks3.StartsWith("1");
}
Does this help, or have I misunderstood you?

C#: PictureBox override Width

How can i override the Width property of a PictureBox? (i need to set the base.Width, but additional to execute a method)
Following isn't working:
public class l33tProgressBar : PictureBox
{
public override int Width
{
get { return this.Width; }
set
{
myMethod();
base.Width = value;
}
}
}
Width is not virtual, so you cant override it. You can however, overwrite it using the new keyword.
public new int Width
{
get { return base.Width; }
set
{
myMethod();
base.Width = value;
}
}
However, a better option might be to override the SizeChanged (docs) event handler instead
public override void OnSizeChanged(EventArgs e)
{
// Width or Height has been changed
base.OnSizeChanged(e); // Essential, or event will not be raised!
}
Creating a method for it would probably be cleaner. Hiding a method call in what others would expect to be an inherited property isn't a readable or maintainable approach.
public class l33tProgressBar : PictureBox
{
public void SetWidthMyWay(int width)
{
myMethod();
this.Width = width;
}
}

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