Develop Reference

Large string in label causing application to hang (C# Windows)

I am having an windows application where I am fetching data from db and binding that to a label. I am using timer and scrolling the label, this works fine when the string is around 150 characters but when I have string of around 30000 characters it just hangs out the application.
lblMsg1.AutoEllipsis = true;
private void timer1_Tick(object sender, EventArgs e)
{
try
{
if (lblMsg1.Right <= 0)
{
lblMsg1.Left = this.Width;
}
else
lblMsg1.Left = lblMsg1.Left - 5;
this.Refresh();
}
catch (Exception ex)
{
}
}
public void bindData()
{
lblMsg.Text = "Some Large text";
}
public void Start()
{
try
{
timer1.Interval = 150;
timer1.Start();
}
catch (Exception ex)
{
Log.WriteException(ex);
}
}
Why is this related to string length and causing application to hang? Thanks in advance.

I guess you are trying to create a news ticker?
I am not sure that labels are designed to hold such big strings.
Use a picturebox instead and update your code.
Define two variables in your form class. One to hold text offset and the other to hold the graphics object for the picture box. Like this:
private float textoffset = 0;
System.Drawing.Graphics graphics = null;
In the form onload do this:
private void Form1_Load(object sender, EventArgs e)
{
textoffset = (float)pictureBox1.Width; // Text starts off the right edge of the window
pictureBox1.Image = new Bitmap(pictureBox1.Width, pictureBox1.Height);
graphics = Graphics.FromImage(pictureBox1.Image);
}
Your timer should then look like this:
private void timer1_Tick(object sender, EventArgs e)
{
graphics.Clear(BackColor);
graphics.DrawString(newstickertext, new Font(FontFamily.GenericMonospace, 10, FontStyle.Regular), new SolidBrush(Color.Black), new PointF(textoffset, 0));
pictureBox1.Refresh();
textoffset = textoffset-5;
}

Instead of a Label, use a TextBox and set the ScrollBars, MultiLine and WordWrap properties according to your needs. To disable editing of the TextBox (and, thus, make it behave similar to a label), use the ReadOnly property.

c# real time update a chart

Here I have a chart (graph1) that normally should add a random point every 1second. but it doesn't... I tried to find out what the problem is but here I don't have anymore ideas...
The timer is started, label1 change every seconds but the chart doesn't change... with button one when I click it adds a new point.
what did I miss? please help... thanks a lot.
namespace Test_Chart1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
graph1.ChartAreas[0].AxisX.ScrollBar.Enabled = true;
graph1.ChartAreas[0].AxisX.IsLabelAutoFit = true;
graph1.ChartAreas[0].AxisX.ScaleView.Size = 40;
System.Timers.Timer _Timer1s = new System.Timers.Timer(1000); //object
_Timer1s.Elapsed += _Timer1sElapsed; //event in object
_Timer1s.Start(); //start counting
}
private void _Timer1sElapsed(object sender, EventArgs e)//Timer each 100ms
{
if (label1.BackColor == Color.Red)
{
label1.BackColor = Color.Blue;
PutValueInGraph1();
}
else label1.BackColor = Color.Red;
}
private void button1_Click(object sender, EventArgs e)
{
PutValueInGraph1();
}
private void PutValueInGraph1()
{
graph1.ChartAreas[0].AxisX.ScrollBar.Enabled = true;
graph1.ChartAreas[0].AxisX.IsLabelAutoFit = true;
graph1.ChartAreas[0].AxisX.ScaleView.Size = 100;
Random Rand_Value = new Random();
int ValueToAdd = Rand_Value.Next(1, 100);
listBox1.Items.Add(ValueToAdd.ToString());
graph1.Series["Data1"].Points.AddY(ValueToAdd);
if (graph1.ChartAreas[0].AxisX.Maximum-10 > graph1.ChartAreas[0].AxisX.ScaleView.Size)
{
graph1.ChartAreas[0].AxisX.ScaleView.Scroll(graph1.ChartAreas[0].AxisX.Maximum);
graph1.Series["Data1"].Points.RemoveAt(0);
}
}
}
}
ok here is the new one:
public partial class Form1 : Form
{
static System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
public Form1()
{
InitializeComponent();
myTimer.Tick += new EventHandler(TimerEventProcessor);
myTimer.Interval = 1;
}
private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
{
Random Rand_Value = new Random();
int ValueToAdd = Rand_Value.Next(1, 100);
listBox1.Items.Add(ValueToAdd.ToString());
graph1.Series["Data1"].Points.AddY(ValueToAdd);
if (graph1.ChartAreas[0].AxisX.Maximum - 10 > graph1.ChartAreas[0].AxisX.ScaleView.Size)
{
graph1.ChartAreas[0].AxisX.ScaleView.Scroll(graph1.ChartAreas[0].AxisX.Maximum);
graph1.Series["Data1"].Points.RemoveAt(0);
}
}
private void btn_Start_Click_1(object sender, EventArgs e)
{
graph1.ChartAreas[0].AxisX.ScrollBar.Enabled = true;
graph1.ChartAreas[0].AxisX.IsLabelAutoFit = true;
graph1.ChartAreas[0].AxisX.ScaleView.Size = 100;
myTimer.Start();
BlinkLed.BackColor = Color.YellowGreen;
}
private void btn_Stop_Click(object sender, EventArgs e)
{
myTimer.Stop();
BlinkLed.BackColor = Color.AliceBlue;
}
}
Do you think it's better?
What about the changing thread?
If I had a button:
private void PutValueInGraph1()
{
Random Rand_Value = new Random();
int ValueToAdd = Rand_Value.Next(1, 100);
listBox1.Items.Add(ValueToAdd.ToString());
graph1.Series["Data1"].Points.AddY(ValueToAdd);
if (graph1.ChartAreas[0].AxisX.Maximum-10 > graph1.ChartAreas[0].AxisX.ScaleView.Size)
{
graph1.ChartAreas[0].AxisX.ScaleView.Scroll(graph1.ChartAreas[0].AxisX.Maximum);
graph1.Series["Data1"].Points.RemoveAt(0);
}
}
private void button1_Click(object sender, EventArgs e)
{//try to raise exception
PutValueInGraph1();
}
and I change the event like this:
private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
{//try to raise exception
PutValueInGraph1();
}
The data input accelerate when I'm started the timer and I click all the time on the button1.
Why is there no exception as tom_imk said??
because we can access the same function at the same time....?
Thanks for your answers.

I tried below sample code and it is working fine for me.
public Form7()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
chart1.ChartAreas[0].AxisX.Maximum = 100;
chart1.ChartAreas[0].AxisX.Minimum = 0;
chart1.ChartAreas[0].AxisX.Interval = 1;
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
Random Rand_Value = new Random();
int ValueToAdd = Rand_Value.Next(1, 100);
chart1.Series[0].Points.AddY(ValueToAdd);
}

I'm surprised you didn't get an exception. You are manipulating UI elements outside the UI thread, something you musn't do, ever.
Refer to the answer in this question:
How to update the GUI from another thread in C#?
EDIT:
To make clear why the timerelapsed method does not run on the UI thread: It's simply the wrong class that is used here. So the easy solution would be to not created a System.Timers.Timer in the Form-constructor but to drop a timer on the form in the form designer and use that instead. The solution by sowjanya attaluri should be marked as the correct answer.

How to add textboxs to the dynamically created pictureboxes

I have a program which dynamically creates movable pictureboxes when I click on buttons. I need to do something like when I click on the picturebox, this click adds to my dynamically created picturebox a new textbox when I can write descripiton of this picturebox(name,...). This textbox should be able to move with picturebox.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
List<PictureBox> pictureboxes = new List<PictureBox>();
public Form1()
{
InitializeComponent();
}
private void AddPictureBox(string imagePath)
{
var pb = new PictureBox();
pb.Name = "picturebox" + pictureboxes.Count;
pb.Location = new Point(pictureboxes.Count * 100, 100);
pb.Size = new Size(70, 70);
pb.BorderStyle = BorderStyle.None;
pb.SizeMode = PictureBoxSizeMode.StretchImage;
this.Controls.Add(pb);
pb.Image = Image.FromFile(imagePath);
pb.Refresh();
pb.MouseDown += new MouseEventHandler(picMouseDown);
pb.MouseMove += new MouseEventHandler(picMouseMove);
pb.MouseUp += new MouseEventHandler(picMouseUp);
pictureboxes.Add(pb);
Invalidate();
}
private void router_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\\router.jpg");
}
private void Form1_Load(object sender, EventArgs e)
{
}
int x = 0;
int y = 0;
bool drag = false;
private void picMouseDown(object sender, MouseEventArgs e)
{
// Get original position of cursor on mousedown
x = e.X;
y = e.Y;
drag = true;
}
private void picMouseMove(object sender, MouseEventArgs e)
{
if (drag)
{
PictureBox pb = (PictureBox)sender;
// Get new position of picture
pb.Top += e.Y - y;
pb.Left += e.X - x;
pb.BringToFront();
Invalidate();
}
}
private void picMouseUp(object sender, MouseEventArgs e)
{
drag = false;
}
private void switch1_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\Grafika\switch1.png");
}
private void panel1_Paint(object sender, PaintEventArgs e)
{
}
private void pc_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\pc.jpg");
}
private void server_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\server.png");
}
}
Thanks for any help :).

You can add a TextBox to a PictureBox in code like this:
TextBox newTextBox = new TextBox();
newTextBox.Parent = yourPictureBox;
// place it e.g. to the left bottom:
newTextBox.Location = new Point(10, yourPictureBox.Height - newTextBox.Height);
Note that this will add the TextBox to the Controls collection of the PB; so it will sit on top of the PictureBox; so, yes, it will move with the PictureBox but it will also hide a part or the PB!
If instead you simply want to group them, add them both to something like a Panel, again by setting that as their Parent!
Also note that you can't do this in the Designer; PictureBox is not really meant to act as a Container..
It doesn't matter how the PictureBox was created, as long as you have a reference to it.

Update multiple pictureboxes at the same time

I have four PictureBoxes (each PictureBox represents one dice) and a Timer that changes every 100ms source pictures (loaded in memory as List<Bitmap> imagesLoadedFromIncludedResources).
Code:
private List<PictureBox> dices = new List<PictureBox>();
private void timer_diceImageChanger_Tick(object sender, EventArgs e)
{
foreach (PictureBox onePictureBox in dices)
{
oneDice.WaitOnLoad = false;
onePictureBox.Image = //... ;
oneDice.Refresh();
}
}
I need to change all the images at once - at this moment, you can see that the images are changing from left to right with a small delay.
I tried variant with one Thread for each PictureBox (using Control.Invoke method from this answer) - it is visually little better but not perfect.

You can try to suspend form's layout logic:
SuspendLayout();
// set images to pictureboxes
ResumeLayout(false);

Parallel.ForEach
(
dices,
new ParallelOptions { MaxDegreeOfParallelism = 4 },
(dice) =>
{
dice.Image = ...;
dice.WaitOnLoad = false;
dice.Refresh();
}
);
The problem is that UI controls can only be accessed from the UI thread. If you want to use this approach, you must create a copy of your PictureBoxes and then replace the UI ones once the operation is done.
Another approach would be creating two PictureBoxes, with the first one just on the top of the other one (hiding the latter)... you change all the images and then, once the processing is complete, you iterate all the ones in the back putting them on the top which would result in a lesser delay.

I'd approach this differently - it's been a while since I've played with WinForms stuff, but I'd probably take more control over the rendering of the images.
In this example I've got the images all in one source bitmap stacked vertically, stored as a resource in assembly:
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
private Timer timer;
private Bitmap dice;
private int[] currentValues = new int[6];
private Random random = new Random();
public Form1()
{
InitializeComponent();
this.timer = new Timer();
this.timer.Interval = 500;
this.timer.Tick += TimerOnTick;
this.dice = Properties.Resources.Dice;
}
private void TimerOnTick(object sender, EventArgs eventArgs)
{
for (var i = 0; i < currentValues.Length; i++)
{
this.currentValues[i] = this.random.Next(1, 7);
}
this.panel1.Invalidate();
}
private void button1_Click(object sender, EventArgs e)
{
if (this.timer.Enabled)
{
this.timer.Stop();
}
else
{
this.timer.Start();
}
}
private void panel1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.Clear(Color.White);
if (this.timer.Enabled)
{
for (var i = 0; i < currentValues.Length; i++)
{
e.Graphics.DrawImage(this.dice, new Rectangle(i * 70, 0, 60, 60), 0, (currentValues[i] - 1) * 60, 60, 60, GraphicsUnit.Pixel);
}
}
}
}
}
The source is here if it helps: http://sdrv.ms/Wx2Ets

moving a button using a timer

I have four buttons that are called "ship1,ship2" etc.
I want them to move to the right side of the form (at the same speed and starting at the same time), and every time I click in one "ship", all the ships should stop.
I know that I need to use a timer (I have the code written that uses threading, but it gives me troubles when stopping the ships.) I don't know how to use timers.
I tried to read the timer info in MDSN but I didn't understand it.
So u can help me?
HERES the code using threading.
I don't want to use it. I need to use a TIMER! (I posted it here because it doesnt give me to post without any code
private bool flag = false;
Thread thr;
public Form1()
{
InitializeComponent();
}
private void button2_Click(object sender, EventArgs e)
{
flag = false;
thr = new Thread(Go);
thr.Start();
}
private delegate void moveBd(Button btn);
void moveButton(Button btn)
{
int x = btn.Location.X;
int y = btn.Location.Y;
btn.Location = new Point(x + 1, y);
}
private void Go()
{
while (((ship1.Location.X + ship1.Size.Width) < this.Size.Width)&&(flag==false))
{
Invoke(new moveBd(moveButton), ship1);
Thread.Sleep(10);
}
MessageBox.Show("U LOOSE");
}
private void button1_Click(object sender, EventArgs e)
{
flag = true;
}

Have you googled Windows.Forms.Timer?
You can start a timer via:
Timer timer = new Timer();
timer.Interval = 1000; //one second
timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
timer.Enabled = true;
timer.Start();
You'll need an event handler to handle the Elapsed event which is where you'll put the code to handle moving the 'Button':
private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
MoveButton();
}