Original Question: Edit properties of Graphics object c#
I've managed to create the object models and converted the entire program to use this structure so many thanks for the template there. My only problem is, I need to use threading to implement the color-changing feature. I have implemented the following code but have no luck:
private void pictureBox6_Click(object sender, EventArgs e)
{
running = !running;
}
public void redgreenMethod()
{
while (true)
{
if (running != true) continue;
if (flag == false)
{
flag = true;
Shape x = shapes[methodCounter - 1];
x.pen = Red;
}
else
{
flag = false;
Shape x = shapes[methodCounter];
x.pen = Green;
}
Thread.Sleep(500);
}
}
Surely the code inside the "if" statement changes the pen for the most recently added shape? I've entered a breakpoint and it shows that the pen does change constantly.. however, I don't see this being implemented on the Canvas?!
Where am I going wrong?!
From my previous comment:
Most likely redgreenMethod() is running in the main UI thread and the
tight loop is preventing the controls from updating themselves. Use a
TIMER instead. Set its Interval property to 500, and handle the Tick()
event. You don't need the while loop then. Instead of running you just
toggle the Enabled state of the Timer.
Here's what that might look like in code:
private void pictureBox6_Click(object sender, EventArgs e)
{
timer1.Enabled = !timer1.Enabled;
}
private void timer1_Tick(object sender, EventArgs e)
{
flag = !flag;
shapes[methodCounter - 1].pen = flag ? Green : Red;
}
You made these comments in an answer to your previous question:
Once a line has been drawn via the graphics: "g.DrawLine", the
properties of this line are then inaccessible. I need to find out how
to actually access these properties so I can use them inside the
Thread method.
In short, you DON'T access the properties of the line that has already been drawn. What you would do is update the color in the Shape (which you're already doing), and then call Invalidate() against the control that needs to be redrawn, such as pictureBox6.Invalidate(). This will force the Paint() event to fire again where everything will then be re-drawn, presumably with the new color that was set in the Shape properties.
Related
I don't know if I still have missing on this but whenever you want to add PictureBox, you just find it on Toolbox and drag it on the UI. But what I did is I coded it by adding PictureBox then what I want is I have to move it to the right. I coded it on a Timer and this is how I do.
private void enemyMove_Tick(object sender, EventArgs e)
{
GameMenu menu = new GameMenu();
if (menu.cmbox_Level.Text.Equals("Easy"))
{
this.Controls.Add(menu.EnemyTank);
menu.EnemyTank.Width = 26;
menu.EnemyTank.Height = 32;
menu.EnemyTank.BackgroundImage = Properties.Resources.Tank_RIGHT_v_2;
menu.EnemyTank.BackgroundImageLayout = ImageLayout.Stretch;
menu.EnemyTank.Left += 2;
}
}
Don't ask me if the Timer is started. Yes it already started, it was coded on the Form. But somehow when I start the program it doesn't move. But then I tried adding PictureBox, this time I tried dragging it to UI then add an Image on it, then coded it by moving to the right. When I start the program it works. But what I want is that whenever I start the button it will just make the random PictureBox move to the right. Idk what's the missing in here.
I made some assumptions. If I my assumptions aren't correct, please update your post for details. Following content is copied from my comment.
A new GameMenu will always create a new EnemyTank.
A EnemyTank's default Left value is fixed;
Your enemyMove_Tick is keep creating GameMenu and EnemyTank.
That is, every tick, a EnemyTank is created and value changed to "default value plus 2" in your code.
To avoid it, you have to keep EnemyTank instance somewhere instead of keep creating it.
Here's a example.
GameMenu m_menu;
void YourConstructor()
{
// InitializeComponent();
// something else in your form constructor
m_menu = new GameMenu();
m_menu.EnemyTank.Width = 26;
m_menu.EnemyTank.Height = 32;
m_menu.EnemyTank.BackgroundImage = Properties.Resources.Tank_RIGHT_v_2;
m_menu.EnemyTank.BackgroundImageLayout = ImageLayout.Stretch;
this.Controls.Add( m_menu.EnemyTank );
}
private void enemyMove_Tick(object sender, EventArgs e)
{
if (menu.cmbox_Level.Text.Equals("Easy"))
{
m_menu.EnemyTank.Left += 2;
}
}
I am attempting to generate a set of rectangles on an image. To achieve this, I call a method that is present in a seperate class (Because multiple forms need to call this function.) Let's say I have Form A and Form B that both need to draw said set of rectangles:
From Form A it works just fine, from Form B it doesn't draw anything, but it doesn't return an exception either.
To make sure I haven't missed anything, I went as far as to copy and paste the function calls from both forms so the two of them are identical. I have also triple checked any semantic errors but have been unable to find any.
The function call from Form A is as follows:
private void PbPreview_Click(object sender, EventArgs e)
{
if (NewPage) //This bool is true when the user is displaying a new page(Image)
{
StartingY = MousePosition.Y - 76; //Save the Y position of the click in a float variable
Form1.MainController.DrawRect(StartingY, PbPreview.Image); //Function call
NewPage = false; //Set the new Page bool to false to prevent overdrawing
}
}
The function call from Form B is as follows:
private void PbFactuur_Click(object sender, EventArgs e)
{
if (NewPage) //Same use as the NewPage bool from above
{
MouseY = MousePosition.Y - 76; //Saving mouse position
Form1.MainController.DrawRect(MouseY, PbFactuur.Image); //Function call
NewPage = false; //Set new page to false to prevent overdrawing
MessageBox.Show("I have executed the function"); //Debug info
}
}
And here is the code that is present within the function:
public void DrawRect(float Ypos, Image DrawSubject)
{
try
{
foreach (Rectangle R in Form1.nieuwBedrijf.Rects)
{
Rectangle TempRect = R;
TempRect.Y = Convert.ToInt32(Ypos);
Graphics G = Graphics.FromImage(DrawSubject);
G.DrawRectangle(Pens.Black, TempRect.X * Form1.nieuwBedrijf.ScaleX, TempRect.Y * Form1.nieuwBedrijf.ScaleY, TempRect.Width * Form1.nieuwBedrijf.ScaleX, 1920);
}
}
catch
{
MessageBox.Show("No rectangles have been defined yet.");
}
}
Sidenote: Rects is a list of user defined rectangles.
The expected result would be that at the location where the user clicks, the set of rectangles will appear. But in reality, nothing appears at all.
The application doesn't return any sort of error message, and with the use of breakpoints and messageboxes I have been able to verify that the function does execute.
I hope anyone is able to point me to a potential solution to this problem.
Many thanks in advance
~Melvin
After some tinkering around I have found the following solution:
The rectangles were actually being drawn, but it was not being shown on screen. To have the rectangles show up on screen, I had to add the following line of code:
private void PbFactuur_Click(object sender, EventArgs e)
{
if (NewPage) //Same use as the NewPage bool from above
{
MouseY = MousePosition.Y - 76; //Saving mouse position
Form1.MainController.DrawRect(MouseY, PbFactuur.Image); //Function call
NewPage = false; //Set new page to false to prevent overdrawing
MessageBox.Show("I have executed the function"); //Debug info
Refresh();//<----- This line fixed the problem
}
}
I'm C# with Compact Framework and I realized something weird today. I'm calling a method by an event that applies a set to an object and when I debug, it passes by this, but just performs after the last close bracket of the method. My example:
public string Loading
{
set { lblLoading.Text = value; }
}
private void btnAuth_Click(object sender, EventArgs e)
{
Loading = "Loading...";
_presenter.PerformAuth();
}
When I debug, it passes by my first statement, applies it, but doesn't change anything on the screen... Oh, until it do PerformAuth(). After it, so, then the label value is changed. Oh, the problem isn't just by it be synchronous. The same occurs when I try to do an asynchronous task:
private void btnAuth_Click(object sender, EventArgs e)
{
ASyncResult res = BeginInvoke(new Action(() =>Loading = "Loading..."));
EndInvoke(res);
_presenter.PerformAuth();
}
I think it might be a bug in thread and in C# design implementation. And also with direct set it is stubborn to me. As you can see in the image below:
I just want to set a text in a label, call a method and unset it in an event. Why does C# get it so complicated?
So, I'm trying to develop a simple application in visual C# which gets data from serial port and displays it in a textbox (to monitor temperature). I'm acquiring and displaying the data successfully, using the DataReceived event to update a global string variable and a timer to update the text field on my text box, as shown:
private void port_DataReceived_1(object sender, SerialDataReceivedEventArgs e)
{
try
{
globalVar.updateTemp = port.ReadLine(); //This is my global string
}
catch (IOException)
{
}
catch (InvalidOperationException)
{
}
catch (TimeoutException)
{
}
}
private void timer1_Tick(object sender, EventArgs e)
{
tempDisplayBox.Text = globalVar.updateTemp; //This is my textbox updating
}
The only issue I have is that the value shown in the textbox keeps flashing, making it hard to read. My timer is set to trigger every 10 ms (which should be fast enough, right?). Is there any way to make it more stable? I realize this may be a newb question, but to be fair I am a newb :) Any help is appreciated! Thanks!
Do you really need it updating every 10ms? What about every 500 ms or if not that then 100ms. 100ms will require your update method run 10 times less and therefore update 10 times less. The flickering you are expiriencing is due to the refresh speed. You could create custom method which will only update the temp only when target Label or textBox value is different than source port. But that will only sort the flickering when temp is steady, when temp will start vary it will bring back the flickering. Good luck ;-)
UPDATE
Hi I tried to reproduce the conditions and could not make my textbox nor Label flash. The way I tested it was by assigning int ntick = 0; and then increment the ++ntick; inside of the timer_tick method. The results didn't make any of the controls flash and were updated even every milisecond at some point. I also tried string.Format to put some load on the method. Is your app responsive?
The trick is to use double buffering. This way the operating system will redraw the Control off-screen, and only show the control when it is fully redrawn.
I have had the same problem, and solved it by extending the TextBox control like this:
public FastLogBox()
{
InitializeComponent();
_logBoxText = new StringBuilder(150000);
timer1.Interval = 20;
timer1.Tick += timer1_Tick;
timer1.Start();
SetStyle(ControlStyles.DoubleBuffer, true);
}
void timer1_Tick(object sender, EventArgs e)
{
if (_timeToClear)
{
_logBoxText.Clear();
_timeToClear = false;
}
if (_logQueue.Count <= 0) return;
while (!_logQueue.IsEmpty)
{
string element;
if (!_logQueue.TryDequeue(out element)) continue;
{
_logBoxText.Insert(0, element + "\r\n");
}
}
if (_logBoxText.Length > 150000)
{
_logBoxText.Remove(150000, _logBoxText.Length - 150001);
}
Text = _logBoxText.ToString();
}
public new void Clear()
{
_timeToClear = true;
while (!_logQueue.IsEmpty)
{
string element;
_logQueue.TryDequeue(out element);
}
}
public void AddToQueue(string message)
{
_logQueue.Enqueue(message);
}
}
I also use a timer and a concurrentQueue to avoid using Invoke to update the control from another thread. I also use a StringBuilder to prepare the string before putting it into the TextBox. StringBuilder is faster when building larger strings.
You can use ReadExisting() to read the whole data at a time.
You need to handle DataReceived Event of SerialPort
serialPort1.ReadExisting();
Sample:
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
String myData=serialPort1.ReadExisting();
}
Example Code: Here i would like to show you the code to Read Data(RFID Tag Code which is basically of length 12)
String macid = "";
private void DoWork()
{
Invoke(
new SetTextDeleg(machineExe ),
new object[] { macid });
macid = "";
}
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
string str1;
macid += serialPort1.ReadExisting();
if (macid.Length == 12)
{
macid = macid.Substring(0, 10);
Thread t = new Thread(new ThreadStart(DoWork));
t.Start();
}
}
public void machineExe(string text)
{
TextBox1.Text=text;
}
Thank you so much for the answers! I found a way to work around this issue:
Instead of replacing the contents of my textbox by rewriting the TextBox.Text property - which, as HenningNT implied, refreshes the control and causes the flickering - I'm now using the TextBox.AppendText method. Though, as I want to display only one line of data at a time, I use the textbox in multiline mode and the Environment.NewLine to jump to a new line before appending the text. As for the method of updating, I've gone back to using the timer because with the invoke method was crashing my application when I close the form, for some reason. Also, enabling double buffering didn't do me much good, although I guess I was doing it wrong... It still flickers a bit, but it's much better now :) I know this is not really a perfect solution (much more of a workaround), so I'll keep looking for it. If I find it, I'll be sure to update it here ;) My code:
private void timer1_Tick(object sender, EventArgs e) //Timer to update textbox
{
if (tempDisplayBox.Text != globalVar.updateTemp) //Only update if temperature is different
{
try
{
tempDisplayBox.AppendText(Environment.NewLine);
tempDisplayBox.AppendText(globalVar.updateTemp);
}
catch (NullReferenceException)
{
}
}
}
I did quite a bit of searching around and didn't find anything of much help.
Is it possible to "slide" or "move" using C#, an object from one Location to another using a simple For loop?
Thank you
I would suggest you rather use a Timer. There are other options, but this will be the simplist if you want to avoid threading issues etc.
Using a straight for loop will require that you pump the message queue using Application.DoEvents() to ensure that windows has the opportunity to actually render the updated control otherwise the for loop would run to completion without updating the UI and the control will appear to jump from the source location to the target location.
Here is a QAD sample for animating a button in the Y direction when clicked. This code assumes you put a timer control on the form called animationTimer.
private void button1_Click(object sender, EventArgs e)
{
if (!animationTimer.Enabled)
{
animationTimer.Interval = 10;
animationTimer.Start();
}
}
private int _animateDirection = 1;
private void animationTimer_Tick(object sender, EventArgs e)
{
button1.Location = new Point(button1.Location.X, button1.Location.Y + _animateDirection);
if (button1.Location.Y == 0 || button1.Location.Y == 100)
{
animationTimer.Stop();
_animateDirection *= -1; // reverse the direction
}
}
Assuming that the object you're talking about is some kind of Control you could just change the Location property of it.
So something like this:
for(int i = 0; i < 100; i++)
{
ctrl.Location.X += i;
}
Should work I think.