I am new to c# and I am using windows forms.
I have form1 with 3 buttons. I am trying to set the 3 buttons so they appear one by one when/after the form loads . I used the following code but it did not work when I run the program the 3 buttons appear in the same time
private void MainForm_Load(object sender, EventArgs e)
{ //Hide all buttons
button1.Visible = false;
button2.Visible = false;
button3.Visible = false;
Thread.Sleep(500);
//show buttons one by one
button1.Visible = true;
Thread.Sleep(500);
button2.Visible = true;
Thread.Sleep(500);
button3.Visible = true;
}
I do not know what I am doing wrong. Can anyone help me how can I make the 3 buttons appear one by one when/after the form loads. I am happy to receive any other ideas . Thank you
You are blocking the UI thread with Thread.Sleep, and the updates aren't being reflected.
The best you can do is to create an async function and use Task.Delay, in this way the thread will be still responsive and you will see the updates:
private async void MainForm_Load(object sender, EventArgs e)
{ //Hide all buttons
button1.Visible = false;
button2.Visible = false;
button3.Visible = false;
await Task.Delay(500);
//show buttons one by one
button1.Visible = true;
await Task.Delay(500);
button2.Visible = true;
await Task.Delay(500);
button3.Visible = true;
}
The main issue here is that Load is called before the form is rendered. This, combined with the fact that Thread.Sleep blocks the current (UI) thread causes the buttons to all be made visible before the form actually renders.
You can solve this by using the Form.Shown event and making your pauses asynchronous.
private async void Shown(Object sender, EventArgs e) {
var buttons = new[] {button1, button2, button3};
foreach (var button in buttons)
{
await Task.Delay(TimeSpan.FromMilliseconds(500));
button.Visible = true;
}
}
Make sure that your buttons still get initiated with Visible = false;
Set the Visible of all buttons to False in Form_Load event as you do.
Create a timer with the desired interval and some counter.
Inside the Timer.Tick event, set visibility of your buttons one by one, depending on the counter value, like this:
switch(counter)
{
case 0: button1.Visible = true; break;
case 1: button2.Visible = true; break;
case 2: button3.Visible = true; break;
}
counter++;
Then when all your buttons are visible, disable the timer.
button1.Visible = false;
button2.Visible = false;
Task.Factory.StartNew(() =>
{
Thread.Sleep(2000);
this.Invoke((MethodInvoker)delegate { button1.Visible = true; });
Thread.Sleep(2000);
this.Invoke((MethodInvoker)delegate { button2.Visible = true; });
});
Related
I am trying to disable all buttons I am using after a time period of inactivity using the timer from toolbox. I can currently get it to work by just disabling the relevant buttons in
private void timer1_Tick(object sender, EventArgs e)
but this disables in ten seconds regardless of activity or inactivity.
Is it possible for the timer to work only after 10 seconds of no activity?
Here is the code I am using.
private void timer1_Tick(object sender, EventArgs e) {
button1.Enabled = false;
button2.Enabled = false;
button3.Enabled = false;
button4.Enabled = false;
button5.Enabled = false;
button6.Enabled = false;
button7.Enabled = false;
button8.Enabled = false;
button9.Enabled = false;
button10.Enabled = false;
button11.Enabled = false;
button12.Enabled = false;
button13.Enabled = true;
button14.Enabled = true;
button14.Visible = false;
button15.Enabled = true;
button15.Visible = false;
button17.Enabled = false;
button17.Visible = false;
button18.Visible = false;
button19.Visible = false;
button20.Enabled = false;
textBox1.Visible = false;
textBox2.Visible = false;
textBox3.Visible = false;
textBox4.Visible = false;
checkBox1.Visible = false;
checkBox2.Visible = false;
label15.Visible = false;
label16.Visible = false;
label21.Visible = false;
}
Any help would be greatly appreciated.
Just add the following event to each button that might be clicked and be counted as 'active':
public void ResetTimer(object sender, EventArgs e)
{
timer.Stop();
timer.Start();
}
...
button1.Click += ResetTimer;
The Timer in Winforms doesn't have a Reset method (nor does any of the other timer classes), so you'll have to stop it first and then start it again.
Solution 1:
Reset Time every time user click any button.
Solution 2: ( Not Recommended )
Have a global variable LastActiveTime, Every-time somebody clicks any
button :
LastActiveTime = DateTime.Now()
Parallel running Timer/Thread will check every second if inactive time is more than 10
second and will do accordingly.
I just started learning C#.
Here's my code:
private void button1_Click(object sender, EventArgs e)
{
object Nappi1 = ("Nice button");
MessageBox.Show(Nappi1.ToString());
}
I got a textbox, that should disable the button1 if empty or whitespace.
I already got it working in some level, but it checks the state of the textbox on button1_Click.
private void button1_Click(object sender, EventArgs e)
{
if (textBox1 = "")
{
button1.enabled = false;
}
else
{
button1.enabled = true;
object Nappi1 = ("Nice button");
MessageBox.Show(Nappi1.ToString());
}
}
Fictional example:
if (textBox1 = "" or textBox1 = whitespace[s])
How could I make it check the state of the textbox onLoad (as soon as the program starts)?
How could I make it check if (multiple) whitespace, and can I write it to the same if -statement?
Please keep it simple.
To answer exactly the question title, Shorter, clearer:
button1.Enabled = !string.IsNullOrWhiteSpace(textBox1.Text);
Replace your if-else with this, if it is only a string:
if (string.IsNullOrWhiteSpace(textBox1)) {
button1.enabled = false;
}
else {
button1.enabled = true;
...
}
or use textBox1.Text if it is really a Textbox use this:
if (string.IsNullOrWhiteSpace(textBox1.Text)) {
button1.enabled = false;
}
else {
button1.enabled = true;
...
}
You want String.IsNullOrWhiteSpace:
if (String.IsNullOrWhiteSpace(textBox1.Text)) {
button1.enabled = false;
}
You originally had:
if (textBox1 = "") {
button1.enabled = false;
}
textbox is the control, you need to use the Text property which refers to the string literal inside the textbox control. Also in C# = is an assignment, you ideally would want == which is used to compare.
If you're not using .NET 4 or .NET 4.5 you can use:
String.IsNullOrEmpty
This can be done by using hooking an event handler to text-box text changed event.
Steps:
Attach an event handler for text-box (on text changed)
Inside the text changed event handler enable / disable the button.
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (string.IsNullOrWhiteSpace(textBox1.Text))
button1.Enabled = false;
else
button1.Enabled = true;
}
By default disable the button in InitializeComponent method of form
button1.Enabled = false;
In the textBox1 text changed event, right this code:
button1.Enabled = !string.IsNullOrWhiteSpace(textBox1.Text);
string.IsNullOrWhiteSpace("some text") will check if the text is none or just a wightspaces
if this is true you will set button1.Enabled to false.
I'm trying to make pictures appear, when the element in combobox is selected.
private void Form4_Load(object sender, EventArgs e)
{
if (comboBox1.SelectedIndex == 0)
{
pictureBox1.Visible = true;
pictureBox2.Visible = true;
pictureBox3.Visible = true;
pictureBox4.Visible = true;
}
}
I tried to do it this way, but that doesn't work. Where I’ve made the mistake?
The naming of your method makes me think you're doing that inside the form loading event.
Use the SelectedIndexChanged event of the combobox instead.
i having a little advance with Command Button
lets say i having a form with
label1
label2
label3
And one command button of course
before click the command button
label1.Visible = true;
label2.Visible = false;
label3.Visible = false;
if i click the command button
label1.Visible = false;
label2.Visible = true;
label3.Visible = false;
and then i click again
label1.Visible = false;
label2.Visible = false;
label3.Visible = true;
and repeated again, then back to first before i click the command button
i didnt have any reference on this, so i just make a duplicated command button with same position in form, and i use the visible to get the another command button to be clicked
but it looks not cool,
is there any way better than i make?
you can make one button, and count the number of clicks the user has done, depending on the mod operation you can invoke any of the three method you provide, something like this:
int count = 1; //count clicks
private void ButtonClick(object sender, EventArgs e)
{
if(count%2 == 0)
{
label1.Visible = false;
label2.Visible = true;
label3.Visible = false;
}
else if(count%3 == 0){
label1.Visible = false;
label2.Visible = false;
label3.Visible = true;
}
else{
label1.Visible = true;
label2.Visible = false;
label3.Visible = false;
}
count++;
}
Something similar to this will allow you to only have one command button.
public int visibleLabel = 1;
private void commandButton_Click(object sender, EventArgs e)
{
this.visibleLabel += 1;
if (this.visibleLabel == 4) this.visibleLabel = 1
label1.visble = false;
label2.visble = false;
label3.visble = false;
switch (this.visibleLabel)
{
case 1:
label1.visble = true;
break;
case 2:
label2.visble = true;
break;
case 3:
label3.visble = true;
break;
}
}
Alternatively, you might want to consider having a single label and changing the text (assuming they are in the same locations as well)
Why dont you use a flag to track the current status of the command button? If I understand your question right you want a single command button that sets label2 to visible at first click and label3 visible at second click and label1 visible on third click. Do something like this in the command button click handler:
switch (status)
{
case 0:
{
label1.Visible = false;
label2.Visible = true;
label3.Visible = false;
status = 1;
break;
}
case 1:
{
label1.Visible = false;
label2.Visible = false;
label3.Visible = true;
status = 2;
break;
}
case 2:
{
label1.Visible = true;
label2.Visible = false;
label3.Visible = false;
status = 0;
break;
}
}
Some of the code is redundant, and of course you should have a integer variable called status somewhere in your class. Anyway, this should be fairly understandable and I hope it helps.
I have a button click event for continue:
private void button3_Click(object sender, EventArgs e)
{
if (backgroundWorker1.IsBusy)
{
button2.Enabled = true;
button3.Enabled = false;
}
else
{
backgroundWorker1.RunWorkerAsync();
button2.Enabled = true;
button3.Enabled = false;
}
}
And a button click event for pausing:
private void button2_Click(object sender, EventArgs e)
{
if (backgroundWorker1.WorkerSupportsCancellation == true)
{
backgroundWorker1.CancelAsync();
button3.Enabled = true;
soundPlay = false;
stop_alarm = true;
}
}
The problem is with the button3 click event the continue code sometimes the background is busy so i can enable false/true the buttons but the backgroundworker is keep working.
I want to pause the DoWork event and to continue.
This is my DoWork event:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
while (true)
{
if ((worker.CancellationPending == true))
{
e.Cancel = true;
break;
}
else
{
if (tempCpuValue >= (float?)numericUpDown1.Value || tempGpuValue >= (float?)numericUpDown1.Value)
{
soundPlay = true;
blinking_label();
}
else
{
soundPlay = false;
}
cpuView();
gpuView();
Thread.Sleep(1000);
}
}
}
You could do this with a Thread instead of a BackgroundWorker?
With a Thread, in its working subroutine you could put the thread into an infinite sleep inside a try/catch block that catches ThreadInterruptedException. So, as it loops through whatever it's working on, you could look at the value of a boolean flag to know whether or not to sleep, and then call Thread.Sleep(Timeout.Infinite). When you catch ThreadInterruptedException you set the flag to false and continue to execute.
To make the thread resume from your UI, you would set the 'pause' flag to false and call workerThread.Interrupt() on your thread (assuming you called it workerThread, that is).
Idea sourced from here
You may need to wait until cancellation is done before enable/disable button.
private AutoResetEvent _resetEvent = new AutoResetEvent(false);
private void button2_Click(object sender, EventArgs e)
{
if (backgroundWorker1.WorkerSupportsCancellation == true)
{
backgroundWorker1.CancelAsync();
//Wait statement goes here.
this.Cursor=Cursors.AppStarting;
_resetEvent.WaitOne(); // will block until _resetEvent.Set() call made
button3.Enabled = true;
soundPlay = false;
stop_alarm = true;
}
}
Please see this question:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
while (true)
{
if ((worker.CancellationPending == true))
{
e.Cancel = true;
break;
}
else
{
if (tempCpuValue >= (float?)numericUpDown1.Value || tempGpuValue >= (float?)numericUpDown1.Value)
{
soundPlay = true;
blinking_label();
}
else
{
soundPlay = false;
}
cpuView();
gpuView();
Thread.Sleep(1000);
}
}
_resetEvent.Set(); // signal that worker is done
}