I have a NotifyIcon and I set balloon text with MouseMove event. The balloon text comes from a database. This results continuous database query.
private void notifyIcon1_MouseMove(object sender, MouseEventArgs e)
{
//database operations.......
}
How can I prevent this? I want to set balloon text once when mouse on NotifyIcon.
Use the BalloonTipShown event (https://msdn.microsoft.com/en-us/library/system.windows.forms.notifyicon.balloontipshown(v=vs.110).aspx)
The behaviour you are looking for matched that event alot better then the MouseMove event
Another approach would be to add a Timer to your Form and set its Interval to a delay like 1 second. This delay would be how often the user could hit the database. Setup a Flag that gets reset by the Timer and check it in your NotifyIcon event. Something like:
private bool AllowUpdate = true;
private void notifyIcon1_MouseMove(object sender, MouseEventArgs e)
{
if (AllowUpdate)
{
AllowUpdate = false; // don't allow updates until after delay
// ... hit the database ...
// ... update your text ...
timer1.Start(); // don't allow updates until after delay
}
}
private void timer1_Tick(object sender, EventArgs e)
{
// reset so it can be updated again
AllowUpdate = true;
timer1.Stop();
}
Related
I am working on antivirus program and on real-time protection panel I want checkbox when for example "Malware protection" checkbox is unchecked to make it not enable for like 15 minutes and after that time it is enabled again so it prevents spam.
If somebody can help me it would be great
I tried with Thread.Sleep() but it stops whole application, and I tried with timer but I think I did it wrong.
This is code for timer
private void checkBox1_CheckStateChanged(object sender, EventArgs e)
{
if (this.checkBox1.Checked)
{
this.checkBox1.Text = "On";
// these two pictureboxes are for "You are (not) protected"
// picture
picturebox1.Show();
pictureBox5.Hide();
timer1.Stop();
}
else
{
this.checkBox1.Text = "Off";
// this is the problem
timer1.Start();
this.checkBox1.Enabled = true;
pictureBox1.Hide();
pictureBox5.Show();
}
}
private void timer1_Tick(object sender, EventArgs e)
{
this.checkBox1.Enabled = false;
}
Short Answer
From the code you posted, it really only appears that you need to change the code to disable the checkbox in the CheckChanged event and enable it in the timer1_Tick event (and also Stop the timer in the Tick event).
Full Answer
Winforms has a Timer control that you can use for this. After you drop a Timer onto the designer, set the Interval property to the number of milliseconds you want to wait before enabling the checkbox (1 second is 1000 milliseconds, so 15 minutes is 15min * 60sec/min * 1000ms/sec, or 900,000 ms). Then double-click it to create the Tick event handler (or add one in your Form_Load event as I've done below).
Next, in the CheckChanged event, if the checkbox is not checked, disable the checkbox and start the timer.
Then, in the Tick event, simply enable the checkbox (remember, this event is triggered after Interval milliseconds have passed) and stop the timer.
For example:
private void Form1_Load(object sender, EventArgs e)
{
// These could also be done in through designer & property window instead
timer1.Tick += timer1_Tick; // Hook up the Tick event
timer1.Interval = (int) TimeSpan.FromMinutes(15).TotalMilliseconds; // Set the Interval
}
private void timer1_Tick(object sender, EventArgs e)
{
// When the Interval amount of time has elapsed, enable the checkbox and stop the timer
checkBox1.Enabled = true;
timer1.Stop();
}
private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
if (!checkBox1.Checked)
{
// When the checkbox is unchecked, disable it and start the timer
checkBox1.Enabled = false;
timer1.Start();
}
}
This can be done without using Timer explicitly. Instead use asynchronous Task.Delay, which will simplify the code and make it easy to understand actual/domain intentions.
// Create extension method for better readability
public class ControlExtensions
{
public static Task DisableForSeconds(int seconds)
{
control.Enabled = false;
await Task.Delay(seconds * 1000);
control.Enabled = true;
}
}
private void checkBox1_CheckStateChanged(object sender, EventArgs e)
{
var checkbox = (CheckBox)sender;
if (checkbox.Checked)
{
checkbox.Text = "On";
picturebox1.Show();
pictureBox5.Hide();
}
else
{
checkbox.Text = "Off";
checkbox.DisableForSeconds(15 * 60);
pictureBox1.Hide();
pictureBox5.Show();
}
}
You could diseable and enable it with task.Delay(). ContinueWith(). This creates a new thread that fires after the delay is done. You need to make it thread safe, winforms isnt thread safe on its own
You should use Timer.SynchronizationObject
private void AddMyScrollEventHandlers()
{
VScrollBar vScrollBar1 = new VScrollBar();
}
private void button1_Click(object sender, EventArgs e)
{
while (true)
{
if (vScrollBar1.Value + 1 < vScrollBar1.Maximum)
{
vScrollBar1.Value = vScrollBar1.Value + 1;
label1.Text = vScrollBar1.Value.ToString();
}
else
{
break;
}
System.Threading.Thread.Sleep(200);
}
}
private void button2_Click(object sender, EventArgs e)
{
// vScrollBar1.Scroll
}
I am new in C#. I was working on scroll. What I wanted here is, if anyone click button1 then scroll automatically move to the end and I wanted to show gradual value in label1. Also when someone click button2 scrolling stop.
Now the problem is label1 do not show gradual change in value. It shows value once when the scrolling stop.
Also when scrolling continue i,e when while loop is working I can not click on button2. Actually I can not click on the form even.
Someone please give me some idea how to do this.
This happens because the thread that is performing the task is busy, and it's the same thread that updates the UI. You can use a multithreading solution. Take a look at
BackgroundWorker
All the UI events run in the main thread of the application, so the application can only process one event at a time. When the application is processing an event, no other event will be processed.
Since you are doing a UI related work periodically, the best option is to use the Timer class:
Drop Timer from the toolbox into the form.
In the properties window, set the interval to 200.
Double click the timer object to create the Tick event handler.
Put this code in the newly created timer1_Tick method:
if (vScrollBar1.Value + 1 < vScrollBar1.Maximum)
{
vScrollBar1.Value = vScrollBar1.Value + 1;
label1.Text = vScrollBar1.Value.ToString();
}
else
{
timer1.Stop();
}
Change your methods as below:
private void AddMyScrollEventHandlers()
{
timer1.Start();
}
private void button2_Click(object sender, EventArgs e)
{
timer1.Stop();
}
Now you're done.
I would recommend using BackgroundWorker control, as suggested by Agustin Meriles. However, one more important thing to note is that You should use Control.Invoke(...) method to update controls from another thread.
I've modified Your code, tested it in a sample application and it seems to work correctly.
First, add a new BackgroundWorker control to Your form and assign backgroundWorker1_DoWork to its DoWork event.
Then, You can use the code below:
private void button1_Click(object sender, EventArgs e)
{
//code from here is moved to BackgroundWorker control
backgroundWorker1.RunWorkerAsync();
}
private void button2_Click(object sender, EventArgs e)
{
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
//while (true)
//the condition directly in the while looks more clear to me
while (vScrollBar1.Value + 1 < vScrollBar1.Maximum)
{
//update controls using Invoke method and anonymous functions
vScrollBar1.Invoke((MethodInvoker)delegate() { vScrollBar1.Value += 1; });
label1.Invoke((MethodInvoker)delegate() { label1.Text = vScrollBar1.Value.ToString(); });
//when called inside BackgroundWorker, this sleeps the background thread,
//so UI should be responsive now
System.Threading.Thread.Sleep(200);
}
}
If You have any problems when using this code, please let me know.
Update
As mentioned in the comments, You could also use ProgressChanged event of the BackgroundWorker. It requires some more changes in the code, but is more suitable in this case. You can find some information about it here: http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.progresschanged.aspx.
If You are not going to add any other code with more processing in the while loop, You can also use Timer control, as suggested by MD.Unicorn in his answer.
I currently have a button object that starts a wav file playing, as well as a progress bar and a timer, all of which are toolbox objects in Visual Studio 2010. The problem is that, when I open the form, the progress bar automatically starts filling up. How can I get it to start only when I click on the button?
Here is the code I have so far:
private void playsong1_Click(object sender, EventArgs e)
{
SoundPlayer sndplayer = new SoundPlayer(Programming_assignment.Properties.Resources.Back_In_Black);
sndplayer.Play();
timer1.Enabled = true;
}
private void progressBar1_Click(object sender, EventArgs e)
{
}
private void timer1_Tick(object sender, EventArgs e)
{
if (progressBar1.Value < 256)
{
progressBar1.Value++;
}
}
Looks like you have timer1.Enabled = true or timer1.Start() in form's constructor or Load event handler. BTW check timer's Enabled property in designer - maybe you set it to true by default.
After a button is clicked in a Windows form application written in C#, how to wait for another button to be clicked? Meanwhile I am updating a datagridview dynamically by current information.
EDIT
After button1 is clicked, I want to repeatedly update a dataGridView with current information and when button2 is clicked I want to stop updating the dataGridView.
Use Timer Class.
public partial class Form1 : Form
{
System.Windows.Forms.Timer timer;
public Form1()
{
InitializeComponent();
//create it
timer = new Timer();
// set the interval, so it'll fire every 1 sec. (1000 ms)
timer.Interval = 1000;
// bind an event handler
timer.Tick += new EventHandler(timer_Tick);
//...
}
void timer_Tick(object sender, EventArgs e)
{
//do what you need
}
private void button1_Click(object sender, EventArgs e)
{
timer.Start(); //start the timer
// switch buttons
button1.Enabled = false;
button2.Enabled = true;
}
private void button2_Click(object sender, EventArgs e)
{
timer.Stop(); //stop the timer
// switch buttons back
button1.Enabled = true;
button2.Enabled = false;
}
From MSDN:
A Timer is used to raise an event at user-defined intervals. This
Windows timer is designed for a single-threaded environment where UI
threads are used to perform processing. It requires that the user code
have a UI message pump available and always operate from the same
thread, or marshal the call onto another thread.
When you use this timer, use the Tick event to perform a polling
operation or to display a splash screen for a specified period of
time. Whenever the Enabled property is set to true and the Interval
property is greater than zero, the Tick event is raised at intervals
based on the Interval property setting.
So you have button A and button B. When button A is pressed you want to wait for button B to be pressed, then do something special? Without more information the simplest way is something like this:
private void OnButtonAClicked(object sender, EventArgs e)
{
ButtonA.Enabled = false;
ButtonA.Click -= OnButtonAClicked;
ButtonB.Click += OnButtonBClicked;
ButtonB.Enabled = true;
}
private void OnButtonBClicked(object sender, EventArgs e)
{
ButtonB.Enabled = false;
ButtonB.Click -= OnButtonBClicked;
// Do something truly special here
ButtonA.Click += OnButtonAClicked;
ButtonA.Enabled = true;
}
This code will toggle(initial state; button A is enabled, button B is disabled), when button A is pressed, button B becomes enabled and processes events, etc.
Use the BackgroundWorker http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx
It doesn't freeze the UI, support ProgressBar, also it can be async. At the link you will see a good example with same functional that you want (start some task by click on one button and cancel it by click on another button).
I was wondering if anyone knows how to use a dialog box to create a hold down button event. Here is the scenerio:
a user would like to shutdown their system, but because it is critical that they confirm, that user must hold the button for 5 seconds before the action can be done.
I am trying to do it in a yes no scenario ie.
To confirm shutdown please hold "Yes" for 5 seconds.
Anyone done this before able to offer a little help/insight?
Try using a button's Mouse_Down & Mouse_Up event, and a timer (this assumes you're using WinForms).
private void button1_MouseDown(object sender, MouseEventArgs e)
{
if (this.timer1.Enabled == false)
{
this.timer1.Interval = 5000;
this.timer1.Enabled = true;
}
}
private void timer1_Tick(object sender, EventArgs e)
{
this.timer1.Enabled = false;
MessageBox.Show("Shutdown!");
}
private void button1_MouseUp(object sender, MouseEventArgs e)
{
timer1.Enabled = false;
}
You could capture the button press on 'mousedown', and start a 5-second timer. Once the timer completes, shutdown is initiated. If a 'mouseup' event happens, it could stop and reset the timer.
Sure, handle BOTH the mousedown event and the mouseup event. Start a timer on the mousedown and see how long it has run on the mouseup. Done!
You could do this any number of ways. The first that comes to my mind would be to spin off a thread that waits 5 seconds and is simply aborted if the user's mouse comes back up.
Thread shutdown;
private void button1_MouseDown(object sender, MouseEventArgs e)
{
shutdown = new Thread(()=>ShutDown());
shutdown.Start();
}
private void ShutDown()
{
Thread.Sleep(5000);
Console.Write("5 seconds has elapsed");
// Do something.
}
private void button1_MouseUp(object sender, MouseEventArgs e)
{
if (shutdown != null)
{
shutdown.Abort();
shutdown = null;
}
}
Low overhead and you're not adding additional supporting controls for something this simple.
Why bother when you can just use getAsyncKeyState()? Tell them to hold down 'y' for 5 seconds. You can find a reference here: http://www.pinvoke.net/default.aspx/user32.getasynckeystate
Or you can do it your way and start a timer on MouseDown, then on MouseUp, end the timer and then see if it's more or less than 5 seconds. http://msdn.microsoft.com/en-us/library/system.windows.forms.control.mousedown%28VS.71%29.aspx
You can use the Form.MouseDown events do detect that the user has pressed the mouse button. In the event handler, check to see if cursor is over the button or not (the event is passed in the coordinates of the cursor). You can then enable a timer which will tick in 5 seconds, and perform the shutdown when the timer ticks.
When the user first clicks YES, start a timer that repeatedly checks if the mouse location is inside of the button. After 5 seconds has elapsed, proceed with the shutdown. If the user moves the mouse out of the button, stop the timer.
private DateTime mouseDownTime;
private void Button_MouseDown(object sender, MouseButtonEventArgs e)
{
mouseDownTime = DateTime.Now;
}
private void Button_MouseUp(object sender, MouseButtonEventArgs e)
{
if (mouseDownTime.AddSeconds(5) < DateTime.Now)
MessageBox.Show("You held it for 5 seconds!");
}
You can set up a timer on the MouseDown event, and if the mouse capture changes (check the MouseCaptureChanged event) to false before the timer event fires, cancel the timer.