Develop Reference

Why is the text not showing up on screen?

I'm trying to create a countdown where the text displays, "GAME STARTS IN: " and using a for loop and Thread.Sleep a variable counts down from three. I started by using the designer to create the "game starts in:" part, but after the variable wouldn't show up I moved it to code. Now nothing shows up. This is what I have now in my timer method:
if (!countedDown)
DoCountdown();
Countdown.Hide();
And then in a DoCountdown method:
this.Countdown.BackColor = System.Drawing.Color.Transparent;
this.Countdown.ForeColor = System.Drawing.Color.White;
this.Countdown.Location = new System.Drawing.Point(360, 17);
this.Countdown.Name = "Countdown";
this.Countdown.Font = new System.Drawing.Font("Segoe UI", 12F,
System.Drawing.FontStyle.Regular,
System.Drawing.GraphicsUnit.Point);
this.Countdown.Size = new System.Drawing.Size(185, 24);
this.Countdown.TabIndex = 6;
countedDown = true;
for (int i = 3; i > 0; i--)
{
Countdown.Text = "GAME STARTS IN: " + i;
System.Threading.Thread.Sleep(1000);
}
I put a breakpoint at System.Threading.Thread.Sleep(100) and everything seemed normal. Countdown.Text was equal to "GAME STARTS IN: 3". After trying to integrate the solutions the text doesn't show up. Here is some more context in my code:
This is from my start screen form
private void QuitGame(object sender, EventArgs e)
{
Application.Exit();
}
private void StartMultiplayerGame(object sender, EventArgs e)
{
GameScreen startGame = new GameScreen();
startGame.Show();
Hide();
}

Try something like below. A button is used to start the timer and set the initial values.
int count = 3;
private void button2_Click(object sender, EventArgs e) {
timer1.Interval = 1000;
count = 3;
label1.Text = "GAME STARTS IN: " + count;
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e) {
count--;
if (count != 0) {
label1.Text = "GAME STARTS IN: " + count;
}
else {
timer1.Stop();
label1.Text = "GAME STARTED";
MessageBox.Show(" -> GO");
}
}
Edit per OP comments.
Try the code like this in the start screen form...
private void StartMultiplayerGame(object sender, EventArgs e) {
count = 3;
label1.Text = "GAME STARTS IN: " + count;
timer1.Start();
}
Then change the timer code to...
private void timer1_Tick(object sender, EventArgs e) {
count--;
if (count != 0) {
label1.Text = "GAME STARTS IN: " + count;;
}
else {
timer1.Stop();
label1.Text = "Game Started";
GameScreen startGame = new GameScreen();
startGame.Show();
this.Hide();
}
}

loop blocking the main thread to refresh UI so the required scenario can be archived by moving the loop to a separate method
void doCountDown()
{
for (int i = 10; i > 0; i--)
{
setCountDownText( "GAME STARTS IN: " + i);
System.Threading.Thread.Sleep(1000);
}
}
creating anew thread that start this method
new System.Threading.Thread(new System.Threading.ThreadStart(doCountDown)).Start();
and because of the need to update UI in another thread and to make it safe separate the setText in a separate method that update based on checking required to invoke property this will make it work in all cases
void setCountDownText(string txtValue)
{
if (Countdown.InvokeRequired)
{
Action safeWrite = delegate { setCountDownText(txtValue); };
Countdown.Invoke(safeWrite);
}
else
Countdown.Text = txtValue;
}

The "modern" way to do this is using async/await.
For example, launching the DoCountdown() from a button handler could look like this:
async void testBtn_Click(object sender, EventArgs e)
{
await DoCountdown();
}
async Task DoCountdown()
{
// <Initialisation of Countdown elided for brevity>
for (int i = 3; i > 0; i--)
{
Countdown.Text = "GAME STARTS IN: " + i;
await Task.Delay(1000);
}
}
However, whatever calls DoCountdown() will need to be declared as async, and so on up the call tree.
Note that the only acceptable place to have async void rather than async Task as a return type for an async method is where the method is an event handler such as the button handler in the example above.

C#: How do I stop a timer in the middle of a tick

I set a timer in form1(windows form) to tick every second
private void Form1_Load(object sender, EventArgs e)
{
Timer.Interval = 1000;
Timer.Start;
}
In the timer.tick event, I set it to stop after a certain number of ticks.
private void Timer_Tick(object sender, EventArgs e)
{
if(x == 0)
{
MessageBox.Show("ETC");
Timer.Stop();
}
}
However, I found that the timer.Stop() was not ending the timer, and the message box continued popping up one time every second even after x = 0. Why is this? And how do I stop the timer?
Here is the whole code
private void btnStart_Click(object sender, EventArgs e)
{
checkTiming.Stop();
try
{
timeTick.hour = int.Parse(textBoxHour.Text);
timeTick.min = int.Parse(textBoxMin.Text);
timeTick.sec = int.Parse(textBoxSec.Text);
numRepeat = int.Parse(textBoxRepeat.Text);
timeTick.totalTime = 0;
current = timeTick.hour * 3600 + timeTick.min * 60 + timeTick.sec;
if (timeTick.hour * 3600 + timeTick.min * 60 + timeTick.sec > 0 && timeTick.min <= 60 && timeTick.sec <=60 )
{
memory.listHistory.Add(memory.padMultipleString(textBoxHour.Text, textBoxMin.Text, textBoxSec.Text));
updateListViewHistory(memory.listHistory);
checkTiming.Interval = 1000;
checkTiming.Start();
}
else
{
MessageBox.Show("Please enter a valid value", "Error", MessageBoxButtons.OK);
initialise();
}
}
catch
{
MessageBox.Show("Please enter positive integers to all textBoxes", "Error", MessageBoxButtons.OK);
initialise();
}
}
And here is the tick event
private void checkTiming_Tick(object sender, EventArgs e)
{
timeTick.updateTime(current);
updateTextBoxes();
if(current > 0)
{
current--;
}
if(current == 0)
{
if(numRepeat > 1)
{
numRepeat--;
current = timeTick.totalTime;
//Console.WriteLine(current);
MessageBox.Show(memory.listHistory.Last() + " has elapsed. " + "Repeating " + numRepeat.ToString() + " more times", "Timing has Ended", MessageBoxButtons.OK);
}
if(numRepeat == 1)
{
MessageBox.Show(memory.listHistory.Last() + " has elapsed", "Timing has Ended", MessageBoxButtons.OK);
timeTick.totalTime = 0;
Console.WriteLine(numRepeat);
checkTiming.Stop();
}
}
}
The main problem is at this part
private void checkTiming_Tick(object sender, EventArgs e)
{
timeTick.updateTime(current);
updateTextBoxes();
if(current > 0)
{
current--;
}
if(current == 0)
{
if(numRepeat > 1)
{
numRepeat--;
current = timeTick.totalTime;
//Console.WriteLine(current);
MessageBox.Show(memory.listHistory.Last() + " has elapsed. " + "Repeating " + numRepeat.ToString() + " more times", "Timing has Ended", MessageBoxButtons.OK);
}
if(numRepeat == 1)
{
MessageBox.Show(memory.listHistory.Last() + " has elapsed", "Timing has Ended", MessageBoxButtons.OK);
timeTick.totalTime = 0;
Console.WriteLine(numRepeat);
checkTiming.Stop();
}
}
EVen when numRepeat is 1 and current = 0, the timer does not stop even when I declared it(checkTiming.Stop())

According to the documentation, MessageBox:
Displays a message window, also known as a dialog box, which presents a message to the user. It is a modal window, blocking other actions in the application until the user closes it.
This means that when control reaches the MessageBox.Show line, it stops there until the user closes the message box. This means that Timer.Stop will not be called until the user closes the message box. This is why the timer will still tick.
To fix this, just change the order of the method calls:
checkTiming.Stop();
MessageBox.Show(memory.listHistory.Last() + " has elapsed", "Timing has Ended", MessageBoxButtons.OK);
timeTick.totalTime = 0;
Console.WriteLine(numRepeat);

(C# Windows Forms Apps) How to Restart App

I just finished an exercise from Head First C# where I built a Typing Game. The book leaves it to the reader to figure out how to make it so the player can start a new game once they've lost. After the user loses the game, the window shows the message "Game Over". I would like to have a new window pop up and ask the user if they would like to play again once they've closed out of the game over screen. I'd like there to be two buttons; one that says "no" and one that says "yes". What I'm stuck on is how I should (or would) go about restarting the app if the user decides they want to play again. I'll copy and paste my code below:
namespace _7HeadFirstProject
{
public partial class Form1 : Form
{
Random random = new Random();
Stats stats = new Stats();
public Form1()
{
InitializeComponent();
}
private void timer1_Tick(object sender, EventArgs e)
{
// Add a random key to the ListBox
listBox1.Items.Add((Keys)random.Next(65, 90));
if (listBox1.Items.Count > 7)
{
listBox1.Items.Clear();
listBox1.Items.Add("Game Over");
timer1.Stop();
}
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
// If the user pressed a key that's in the ListBox...
// ... remove it and then make the game a little faster
if (listBox1.Items.Contains(e.KeyCode))
{
listBox1.Items.Remove(e.KeyCode);
listBox1.Refresh();
if (timer1.Interval > 400)
timer1.Interval -= 10;
if (timer1.Interval > 250)
timer1.Interval -= 7;
if (timer1.Interval > 100)
timer1.Interval -= 2;
difficultyProgressBar.Value = 800 - timer1.Interval;
// The user pressed a correct key, so update the Stats object...
// ...by calling its Update() method with the argument true
stats.Update(true);
}
else
{
// The user pressed an incorrect key, so update the Stats object...
// ...by calling its Update() method with the argument false
stats.Update(false);
}
// Update the labels on the StatusStrip
correctLabel.Text = "Correct: " + stats.Correct;
missedLabel.Text = "Missed: " + stats.Missed;
totalLabel.Text = "Total: " + stats.Total;
accuracyLabel.Text = "Accuracy: " + stats.Accuracy + "%";
}
private void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
MessageBox.Show("Would you like to play again?");
if
}
}
}
DIFFERENT CLASS:
namespace _7HeadFirstProject
{
class Stats
{
public int Total = 0;
public int Missed = 0;
public int Correct = 0;
public int Accuracy = 0;
public void Update(bool correctKey)
{
Total++;
if (!correctKey)
{
Missed++;
}
else
{
Correct++;
}
Accuracy = 100 * Correct / Total;
}
}
}

You have the whole game working so leave that form alone. Add another form to your project and then set the new form as the startup form. You can set it as the startup form by opening Program.cs and modifying this line:
// Instead of Form1 put the name of your new form
Application.Run(new Form1());
Double click the new form and put this code in it:
// Note: Your load method may have a different name.
private void Form2_Load(object sender, EventArgs e)
{
this.StartNewGame();
}
private void GameForm_FormClosed(object sender, FormClosedEventArgs e)
{
if (MessageBox.Show("Continue?", "Continue?", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
this.StartNewGame();
}
}
private void StartNewGame()
{
// Your game form may have a different name so change this to that name
var gameForm = new Form2();
gameForm.FormClosed += GameForm_FormClosed;
gameForm.Show();
}
Every time the user presses the yes button on the dialog, you are creating a brand new instance of the form (of the game). In this new form, you can also have an array which keeps track of the total number of games and what the score of each game was so you can show it in case the user selected No. All you need is something like this:
var games = new List<Stats>();
// keep adding to it every time you call StartNewGame() method.

Try this:
if ((MessageBox.Show("Would you like to play again?", "Message", MessageBoxButtons.YesNo)) ==
DialogResult.Yes)
{
Application.Restart();
}

How to pause for loop when pause button is clicked?

When I run the program and try to click the pause button, nothing happens. I am not sure how I can get this to work exactly. I have a bool variable called pause and pause is set to false. Once the pause button is clicked it should set that variable to true. Then the loop checks for that and should display a message to the user. Any help is greatly appreciated!
namespace Practice2
{
public partial class Form1 : Form
{
photocopier printer = new photocopier(500, 2500);
bool pause = false;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void btnStart_Click(object sender, EventArgs e)
{
if (checkText(txtNumberCopies.Text) == true)
{
int numberCopies = Convert.ToInt32(txtNumberCopies.Text);
int toner = Convert.ToInt32(lblTonerAmount.Text);
int paperCapacity = Convert.ToInt32(lblPaperAmount.Text);
if (toner <= 625 && paperCapacity <= 125)
{
txtMessage.Text = "Printer is low on Toner and Paper!";
}
else if (toner <= 625){
txtMessage.Text = "Printer Toner is low!";
}
else if (paperCapacity <= 125)
{
txtMessage.Text = "Printer Paper is low!";
}
else
{
txtMessage.Text = "Printing...";
txtMessage.Refresh();
for (int i = numberCopies; i != 0; i--)
{
int paper = Convert.ToInt32(lblPaperAmount.Text);
paper--;
if (paper == 480 || paper == 380 || paper == 400 || paper == 200)
{
MessageBox.Show("There is a paper Jam! Please remove the Jam and then hit the ok button to continue!", "Important Message", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
if (pause == true)
{
MessageBox.Show("Press the ok button when ready to continue", "Important Message", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
lblPaperAmount.Text = Convert.ToString(Convert.ToInt32(lblPaperAmount.Text) - 1);
lblTonerAmount.Text = Convert.ToString(Convert.ToInt32(lblTonerAmount.Text) - 1);
Thread.Sleep(1000);
}
txtMessage.Text = "Job is completed!";
}
}
}
private void btnAddPaper_Click(object sender, EventArgs e)
{
int paperAmount = Convert.ToInt32(lblPaperAmount.Text);
if (checkText(txtAddPaper.Text) == true && paperAmount <= 500)
{
lblPaperAmount.Text = Convert.ToString(paperAmount + Convert.ToInt32(txtAddPaper.Text));
}
else
{
txtMessage.Text = "Printer paper is at capacity!";
}
}
private bool checkText(string textBox)
{
if (textBox.Equals("") || textBox == null)
{
txtMessage.Text = "Please enter a value in the text box!";
return false;
}
return true;
}
private void btnReplaceToner_Click(object sender, EventArgs e)
{
lblTonerAmount.Text = Convert.ToString(printer.Toner);
}
private void btnPauseCancel_Click(object sender, EventArgs e)
{
pause = true;
}
}
}

The problem is that you're doing the work on the UI thread, so the UI thread is busy and can't process messages (e.g. button click). You need to do the work on a worker thread instead, using BackgroundWorker or Task.Run for instance.

A for loop is on the UI Thread so while the for loop is running you can't do anything with the UI. I suggest that you use a System.Windows.Forms.Timer to do the job. You set the interval to 1 and that will run pretty quickly, but not as quickly as a for loop, though. But interval = 1 is enough for you.
Let me show you:
Timer timer = new Timer () {Interval=1};
to create a new timer object.
enter
timer.Tick +=
in the constructer and press TAB twice and that should generate an event handler. Write the stuff you want to do in the event handler.
Call timer.Stop to pause the timer and timer.Start to start the timer.

How can I catch both single-click and double-click events on WPF FrameworkElement?

I can catch a single-click on a TextBlock like this:
private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
MessageBox.Show("you single-clicked");
}
I can catch a double-click on a TextBlock like this:
private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed)
{
if (e.ClickCount == 2)
{
MessageBox.Show("you double-clicked");
}
}
}
But how do I catch them both on a single TextBlock and differentiate between the two?

You need to fire the event after the click sequence is over... when is that? I suggest using a timer. The MouseDown event would reset it and increase the click count. When timer interval elapses it makes the call to evaluate the click count.
private System.Timers.Timer ClickTimer;
private int ClickCounter;
public MyView()
{
ClickTimer = new Timer(300);
ClickTimer.Elapsed += new ElapsedEventHandler(EvaluateClicks);
InitializeComponent();
}
private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
ClickTimer.Stop();
ClickCounter++;
ClickTimer.Start();
}
private void EvaluateClicks(object source, ElapsedEventArgs e)
{
ClickTimer.Stop();
// Evaluate ClickCounter here
ClickCounter = 0;
}
Cheers!

If you need to detect the difference, I suggest you use a control such as Label that does the work for you:
label.MouseDown += delegate(object sender, MouseEventArgs e)
{
if (e.ClickCount == 1)
{
// single click
}
};
label.MouseDoubleClick += delegate
{
// double click
};
EDIT: My advice was following from documentation on MSDN:
The Control class defines the
PreviewMouseDoubleClick and
MouseDoubleClick events, but not
corresponding single-click events. To
see if the user has clicked the
control once, handle the MouseDown
event (or one of its counterparts) and
check whether the ClickCount property
value is 1.
However, doing so will give you a single click notification even if the user single clicks.

You must use a timer to differentiate between the two. Add a timer to your form in the GUI (easiest that way - it will automatically handle disposing etc...). In my example, the timer is called clickTimer.
private bool mSingleClick;
private void TextBlock_MouseUp(object sender, MouseButtonEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (e.ClickCount < 2)
{
mSingleClick = true;
clickTimer.Interval = System.Windows.Forms.SystemInformation.DoubleClickTime;
clickTimer.Start();
}
else if (e.ClickCount == 2)
{
clickTimer.Stop();
mSingleClick = false;
MessageBox.Show("you double-clicked");
}
}
}
private void clickTimer_Tick(object sender, EventArgs e)
{
if (mSingleClick)
{
clickTimer.Stop();
mSingleClick = false;
MessageBox.Show("you single-clicked");
}
}

I did it this Way and it works perfectly
If e.Clicks = 2 Then
doubleClickTimer.Stop()
ElseIf e.Clicks = 1 Then
doubleClickTimer.Enabled = True
doubleClickTimer.Interval = 1000
doubleClickTimer.Start()
End If
Private Sub doubleClickTimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles doubleClickTimer.Tick
OpenWebPage("abc")
doubleClickTimer.Stop()
End Sub

You are simply can use MouseDown event and count click number, like this:
if (e.ChangedButton == MouseButton.Left && e.ClickCount == 2)
{
// your code here
}

My suggestion, implemented in a UserControl by simply using a Task:
private int _clickCount = 0;
protected override void OnPreviewMouseDown(MouseButtonEventArgs e)
{
_clickCount = e.ClickCount;
}
protected override async void OnPreviewMouseUp(MouseButtonEventArgs e)
{
if (_clickCount > 1)
{
//apparently a second mouse down event has fired => this must be the second mouse up event
//no need to start another task
//the first mouse up event will be handled after the task below
return;
}
await Task.Delay(500);
if (_clickCount == 1)
{
//single click
}
else
{
//double (or more) click
}
}
The drawback of all these solutions is, of course, that there will be a delay before actually responding to the user's action.

You could do it on MouseUp instead of MouseDown. That way you can ask the ClickCount property for the total number of clicks, and decide what to do from that point.

It's my working solution :)
#region message label click --------------------------------------------------------------------------
private Timer messageLabelClickTimer = null;
private void messageLabel_MouseUp(object sender, MouseButtonEventArgs e)
{
Debug.Print(e.ChangedButton.ToString() + " / Left:" + e.LeftButton.ToString() + " Right:" + e.RightButton.ToString() + " click: " + e.ClickCount.ToString());
// in MouseUp (e.ClickCount == 2) don't work!! Always 1 comes.
// in MouseDown is set e.ClickCount succesfully (but I don't know should I fire one clicked event or wait second click)
if (e.ChangedButton == MouseButton.Left)
{
if (messageLabelClickTimer == null)
{
messageLabelClickTimer = new Timer();
messageLabelClickTimer.Interval = 300;
messageLabelClickTimer.Elapsed += new ElapsedEventHandler(messageLabelClickTimer_Tick);
}
if (! messageLabelClickTimer.Enabled)
{ // Equal: (e.ClickCount == 1)
messageLabelClickTimer.Start();
}
else
{ // Equal: (e.ClickCount == 2)
messageLabelClickTimer.Stop();
var player = new SoundPlayer(ExtraResource.bip_3short); // Double clicked signal
player.Play();
}
}
}
private void messageLabelClickTimer_Tick(object sender, EventArgs e)
{ // single-clicked
messageLabelClickTimer.Stop();
var player = new SoundPlayer(ExtraResource.bip_1short); // Single clicked signal
player.Play();
}
#endregion

My issue was with single/double-clicking rows in a DataGrid in WPF. For some reason the ButtonDown events weren't firing, only the OnMouseLeftButtonUp event was. Anyway, I wanted to handle the single-click differently from the double-click. It looks me a little time (I'm sure the solution isn't perfect, but it appears to work) to distill the problem down until I got it down to the below. I created a Task which calls an Action and that Action's target can be updated by a second click. Hope this helps someone!
private Action _clickAction;
private int _clickCount;
private void Grid_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
Debug.WriteLine("Button Click Occurred");
_clickCount++;
if (_clickCount == 1)
{
_clickAction = SingleClick;
}
if (_clickCount > 1)
{
_clickAction = DoubleClick;
}
if (_clickCount == 1)
{
Task.Delay(200)
.ContinueWith(t => _clickAction(), TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => { _clickCount = 0; });
}
}
private void DoubleGridClick()
{
Debug.WriteLine("Double Click");
}
private void SingleGridClick()
{
Debug.WriteLine("Single Click");
}