Develop Reference

Getting a label to insert text slowly

I am trying to insert text to a lable, BUT the text has to be inserted slowly/character by character/letter by letter,
kinda like in old MUD games.
So far I have tried doing this:
private void StoryBox_Click(object sender, EventArgs e)
{
string text = StoryBox.Text;
var index = 0;
var timer = new System.Timers.Timer(2000);
timer.Elapsed += delegate
{
if (index < text.Length)
{
index++;
StoryBox.Text = "This should come out pretty slowly ";
}
else
{
timer.Enabled = false;
timer.Dispose();
}
};
timer.Enabled = true;
}
This is what I have gathered from the site but I don't particularly understand why this isn't working.
As you can see it's under StoryBox_Click.
Is there a way to automate this? So when the program is opened, it counts a couple seconds and THEN starts writing the text out.

Try this:
private async void button1_Click(object sender, EventArgs e)
{
string yourText = "This should come out pretty slowly";
label1.Text = string.Empty;
int i = 0;
for (i = 0; i <= yourText.Length - 1; i++)
{
label1.Text += yourText[i];
await Task.Delay(500);
}
}

You can use the Shown-Event of YourForm when you want to start it after your GUI has been opened.
So reusing your provided code and changing a few things this may work for you:
Add private fields to YourForm class:
private Timer _timer;
private int _index;
private string _storyText;
and initialising it in YourForm constructor
public YourForm()
{
InitializeComponent();
// init private fields;
this._index = 0;
this._storyText = "This should come out pretty slowly";
// Timer Interval is set to 1 second
this._timer = new Timer { Interval = 1000 };
// Adding EventHandler to Shown Event
this.Shown += this.YourForm_Shown;
this._timer.Tick += delegate
{
if (this._index < this._storyText.Length)
{
StoryBox.Text += this._storyText[this._index];
this._index++;
}
else
{
this._timer.Stop();
}
};
}
and the Shown event for YourForm:
private void YourForm_Shown(object sender, EventArgs e)
{
this._timer.Start();
}

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.

WinForms sometimes appear twice and sometimes once

I am confuse at this one, the windows form called "Contact" sometimes called twice after the "Welcome Screen" and sometimes it ("Contact") is called once only. I am pretty sure that I called the form once only.
Here is the code that I am using:
The form below "WelcomeScreen" is the first one called when run the program:
public partial class WelcomeScreen : Form
{
int timeLeft = 5;
Timer _timer = new Timer();
BackgroundWorker _backgroundWorker = new BackgroundWorker();
public WelcomeScreen()
{
InitializeComponent();
_backgroundWorker.WorkerReportsProgress = true;
_backgroundWorker.DoWork += BackgroundWorker_DoWork;
_backgroundWorker.ProgressChanged += BackgroundWorker_ProgressChanged;
_timer.Interval = 1000;
_timer.Tick += Timer_Tick;
}
void WelcomeScreen_Load(object sender, EventArgs e)
{
_backgroundWorker.RunWorkerAsync();
}
void Timer_Tick(object sender, EventArgs e)
{
timeLeft--;
if (timeLeft <= 0)
{
_timer.Stop();
this.Hide();
Contact _contact = new Contact();
_contact.ShowDialog();
this.Close();
}
}
void BackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
if (e.ProgressPercentage <= 300)
{
_timer.Start();
this.label3.Text = "Completed ( " + timeLeft + " ) ";
this.label4.Text = string.Empty;
}
}
void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
for (int i = 0; i <= 300; i++)
{
_backgroundWorker.ReportProgress(i);
System.Threading.Thread.Sleep(200);
}
}
The form below "Contact" is called after the "WelcomeScreen":
public partial class Contact : Form
{
const int CP_NOCLOSE_BUTTON = 0x200;
public Contact()
{
InitializeComponent();
}
void Contact_Load(object sender, EventArgs e)
{
SystemManager.SoundEffect();
}
void button1_Click(object sender, EventArgs e)
{
this.Hide();
Loading _loading = new Loading();
_loading.ShowDialog();
this.Close();
}
protected override CreateParams CreateParams
{
get
{
CreateParams myCp = base.CreateParams;
myCp.ClassStyle = myCp.ClassStyle | CP_NOCLOSE_BUTTON;
return myCp;
}
}
I appreciate your answer!
Thank you

It looks like your Timer is causing the issue, by firing multiple times...
You have this condition inside your timer code:
if (timeLeft <= 0)
And the line before is timeLeft--. After timeLeft becomes 0, it will continue getting smaller (-1, -2, etc) and the form will be shown each time.
A quick fix is to either change the condition to timeLeft == 0 or change the type of timeLeft to a uint. Of course, these are both hacks. The correct fix would be to fix your code to stop the timer from firing when required.

WPF Show each image x seconds how?

I'm trying to make a slideshow with a mediaElement that shows each image in listbox x seconds.
How do I make my code play each image x seconds before continuing?
This code adds all images to a listbox named Listbox1
Dictionary<string, string> Listbox1Dict = new Dictionary<string, string>();
private void SearchBtn_Click(object sender, RoutedEventArgs e)
{
Listbox1.Items.Clear();
FolderBrowserDialog folderDialog = new FolderBrowserDialog();
folderDialog.SelectedPath = "C:\\";
DialogResult result = folderDialog.ShowDialog();
if (result.ToString() == "OK")
FileNameTextBox.Text = folderDialog.SelectedPath;
string directory = FileNameTextBox.Text;
var files = Directory.GetFiles(directory).Where(name => !name.EndsWith(".ini"));
foreach (string file in files)
{
Listbox1.Items.Add(System.IO.Path.GetFileNameWithoutExtension(file));
Listbox1Dict.Add(System.IO.Path.GetFileNameWithoutExtension(file), file);
}
}
This code shows all images in fullscreen but it skips everyone to last image at start.
private void button1_Click_1(object sender, RoutedEventArgs e)
{
foreach (var selected in Listbox1.Items)
{
string s = selected.ToString();
if (Listbox1Dict.ContainsKey(s))
{
mediaElement1.Visibility = Visibility.Visible;
SearchBtn.Visibility = Visibility.Hidden;
Listbox1.Visibility = Visibility.Hidden;
FileNameTextBox.Visibility = Visibility.Hidden;
mediaElement1.Source = new Uri(Listbox1Dict[s]);
mediaElement1.Width = System.Windows.SystemParameters.PrimaryScreenWidth;
mediaElement1.Height = System.Windows.SystemParameters.PrimaryScreenHeight;
this.Background = new SolidColorBrush(Colors.Black);
this.WindowStyle = WindowStyle.None;
this.WindowState = WindowState.Maximized;
}
}
}
Tried this code to make the image play one by one but I get an error. Look on comment on code:
private int currentSongIndex = -1;
void mediaElement1next(object sender, EventArgs e)
{
if(currentSongIndex == -1)
{
currentSongIndex = Listbox1.SelectedIndex;
}
currentSongIndex++;
if(currentSongIndex < Listbox1.Items.Count)
{
mediaElement1.Play(Listbox1.Items[currentSongIndex]); // No overload for method 'Play' takes 1 arguments
}
else
{
// last song in listbox has been played
}
}

I think you need a timer to set your next image. Using the code you're currently using, it will iterate through your list and change the image until you get to the end.
Take a look at DispatcherTimer. You could set it so, at each tick, it would change to the next image. Something like this (just writing off my head)
dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
Then, inside your eventhandler:
private void dispatcherTimer_Tick(object sender, EventArgs e)
{
// get the next image
}
Of course you can use other kinds of timers, but that's the main idea.

Hold your image paths in a list & use the tick event of a timer.
Something like:
List<string> paths = new List<string>();
private void timer1_Tick(object sender, EventArgs e)
{
pictureBox1.Image = getNextImage();
}
private string getNextImage()
{
//code...
}
enter code here
EDIT:
Add a class variable: int index = 0;
On the SearchBtn_Click event, add the results to the list.
//..
foreach (string file in files)
{
paths.Add(file);
}
//..
Then do as I did above and the content of the getNextImage method would be:
private string getNextImage()
{
if(index < paths.Count - 1)
{
index += 1;
}
else
{
index = 0;
}
return paths[index];
}

My idea would be to implement a thread that counted to X and then called a NextImage() function when done.

Something like this:
private void Button_Click_1(object sender, RoutedEventArgs e)
{
if (Listbox1.Items.Count > 0)
{
if (dispatcherTimer.IsEnabled)
dispatcherTimer.Stop();
else
{
curImage = 0;
dispatcherTimer.Start();
}
}
}
private void dispatcherTimer_Tick(object sender, EventArgs e)
{
Dispatcher.Invoke((Action)delegate
{
ShowNextImage();
}, null);
}
private void ShowNextImage()
{
if (curImage >= Listbox1.Items.Count)
curImage = 0;
var selected = Listbox1.Items[curImage];
string s = selected.ToString();
if (Listbox1Dict.ContainsKey(s))
{
mediaElement1.Visibility = Visibility.Visible;
SearchBtn.Visibility = Visibility.Hidden;
Listbox1.Visibility = Visibility.Hidden;
FileNameTextBox.Visibility = Visibility.Hidden;
mediaElement1.Source = new Uri(Listbox1Dict[s]);
mediaElement1.Width = System.Windows.SystemParameters.PrimaryScreenWidth;
mediaElement1.Height = System.Windows.SystemParameters.PrimaryScreenHeight;
this.Background = new SolidColorBrush(Colors.Black);
this.WindowStyle = WindowStyle.None;
this.WindowState = WindowState.Maximized;
}
}
and declaration
DispatcherTimer dispatcherTimer = new DispatcherTimer();
int x = 2; //seconds
private int curImage = 0;
and some construct
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0, 0, x);

How to play next item on playlist with axmediaplayer?

ok i have question, i made this code to play axmediaplayer base on item listed on listbox.
first i make this code to make a list using opendialog :
private string[] files, path;
private void button1_Click(object sender, EventArgs e)
{
if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
files = openFileDialog1.SafeFileNames;
path = openFileDialog1.FileNames;
for (int i = 0; i < files.Length; i++) {
listBox1.Items.Add(files[i]);
}
}
}
and then it play the music when the listbox index changed (when the item on the list box cliked) using this code :
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
axWindowsMediaPlayer1.URL = path[listBox1.SelectedIndex];
}
it works fine, and then i want player to automove to the next song base on item on my listbox. with using events PlayStateChange, so i make this code
private void axWindowsMediaPlayer1_PlayStateChange(object sender, AxWMPLib._WMPOCXEvents_PlayStateChangeEvent e)
{
if (axWindowsMediaPlayer1.playState == WMPLib.WMPPlayState.wmppsMediaEnded)
{
if(listBox1.SelectedIndex < files.Length - 1)
{
listBox1.SelectedIndex = listBox1.SelectedIndex + 1;
}
}
}
the selected index change, but the player doesn't auto play the next song. i must click the play button manually in order to play the list. can anyone help me up?

ok i found it, the solution is to add timer before playing the next song.
first im adding timer, that shoud be timer1. and then i change playstate event to something like this :
private void axWindowsMediaPlayer1_PlayStateChange(object sender, axWMPLib._WMPOCXEvents_PlayStateChangeEvent e)
{
if (axWindowsMediaPlayer1.playState == WMPLib.WMPPlayState.wmppsMediaEnded)
{
timer1.Interval = 100;
timer1.Enabled = true;
}
}
then on the timer i adding tick event, the tick event is something like this :
private void timer1_Tick(object sender, EventArgs e)
{
if (listBox1.SelectedIndex < files.Length - 1)
{
listBox1.SelectedIndex++;
timer1.Enabled = false;
}
else
{
listBox1.SelectedIndex = 0;
timer1.Enabled = false;
}
}
now its work fine ^^

Below functionality worked for me:
private void axWindowsMediaPlayer1_PlayStateChange(object sender, AxWMPLib._WMPOCXEvents_PlayStateChangeEvent e)
{
if ((WMPLib.WMPPlayState)e.newState == WMPLib.WMPPlayState.wmppsMediaEnded)
{
timer1.Interval = 100;
timer1.Start();
timer1.Enabled = true;
timer1.Tick += timer1_Tick;
}
}
private void timer1_Tick(object sender, EventArgs e)
{
/// method to play video list items
myFuntiontoPlayVideo();
timer1.Enabled = false;
}