Make sure only single instance of winform application is runnin - winforms

I want to make ensure that only single instance of my winform app is running. Is there any way that i can accomplish it through visual studio 2008 rather than doing it in code behind

in c# you can do something like this in your Program.cs
static class Program
{
public static FormMain MainForm = null;
/// <summary>
/// The main entry point for the application.
/// </summary>
static Mutex mutex = new Mutex(true, "{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE80}");
[STAThread]
static void Main()
{
if (mutex.WaitOne(TimeSpan.Zero, true))
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
MainForm = new FormMain();
Application.Run(MainForm);
mutex.ReleaseMutex();
}
else
{
// send our Win32 message to make the currently running instance
// jump on top of all the other windows
NativeMethods.PostMessage(
(IntPtr)NativeMethods.HWND_BROADCAST,
NativeMethods.WM_SHOWME,
IntPtr.Zero,
IntPtr.Zero);
}
}
}
and in your mainform put this
protected override void WndProc(ref Message m)
{
if (m.Msg == NativeMethods.WM_SHOWME)
{
ShowMe();
}
base.WndProc(ref m);
}
private void ShowMe()
{
if (WindowState == FormWindowState.Minimized)
{
WindowState = FormWindowState.Normal;
}
// get our current "TopMost" value (ours will always be false though)
bool top = TopMost;
// make our form jump to the top of everything
TopMost = true;
// set it back to whatever it was
TopMost = top;
}

static void Main()
{
if (PriorProcess() != null)
{
MessageBox.Show("Another instance of the app is already running.");
return;
}
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
public static Process PriorProcess()
// Returns a System.Diagnostics.Process pointing to
// a pre-existing process with the same name as the
// current one, if any; or null if the current process
// is unique.
{
Process curr = Process.GetCurrentProcess();
Process[] procs = Process.GetProcessesByName(curr.ProcessName);
foreach (Process p in procs)
{
if ((p.Id != curr.Id) &&
(p.MainModule.FileName == curr.MainModule.FileName))
return p;
}
return null;
}

Related

Using Native Windows On Screen Keyboard in WPF App

I need to use an OnScreenKeyboard Component like Native Windows OSK in my Wpf application. I can call the UI by Process.Start("osk.exe") but the UI appears on top of the main ui window. I want to start the OSK app just bottom of my app. Is this possible with any arguments? -e.g. process.StartInfo.WindowPosition=xxx- I'd prefer to use it before I create my own Component.
OK. I solved my problem with Win32 SetWindowPos method. Sharing if it might help others. Below code is opening and resizing/positioning the Native OSK.exe. It places the keyboard relative to the mouse position.
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public int X;
public int Y;
public static implicit operator Point(POINT point)
{
return new Point(point.X, point.Y);
}
}
[DllImport("user32.dll")]
public static extern bool GetCursorPos(out POINT lpPoint);
public static Point GetCursorPosition()
{
POINT lpPoint;
GetCursorPos(out lpPoint);
//bool success = User32.GetCursorPos(out lpPoint);
// if (!success)
return lpPoint;
}
private void OSKMenuItem_Click(object sender, RoutedEventArgs e)
{
Process osk = new Process();
osk.StartInfo.FileName = "osk.exe";
osk.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
osk.Start();
Task.Delay(1000).ContinueWith((a) => {
Point p = GetCursorPosition();
try
{
IntPtr target_hwnd = FindWindowByCaption(IntPtr.Zero, "On-Screen Keyboard");
if (target_hwnd == IntPtr.Zero)
{
Microsoft.Windows.Controls.MessageBox.Show("Error");
}
SetWindowPos(target_hwnd, IntPtr.Zero, (int)p.X - 200, (int)p.Y, 1300, 600, 0);
}
catch (Exception ex)
{
//throw;
}
});

Accessing parent from UserControl in Silverlight

From inside a UserControl I'm trying to reference a method on its parent.
public partial class Tab3_2Data : UserControl
{
public Tab3_2Data()
{
InitializeComponent();
//MainPage mp = this.Ancestors().OfType<MainPage>().FirstOrDefault();
//var x = VisualTreeHelper.GetParent(this);
//var z = this.Parent;
//var parent = this.Ancestors().Take(1).FirstOrDefault();
// None of the above work.. all come back as null
// Trying to access this method on the parent
//ShowMessage("test", OperationStatus.Green);
Have tried this yet nothing
and
// only available OOB
//mainPage = System.Windows.Application.Current.RootVisual as MainPage;
UserControl being called like:
<!-- Tab 3_2 -->
<controls:TabItem Header="Groups and Roles">
<UserControls:Tab3_2Data />
</controls:TabItem>
EDIT2:
This is how I got it working:
In the UserControl:
UserControl x:Class="xyz.ClientApp.UserControls.Tab3_2Data" Loaded="Tab3_2Data_OnLoaded"
then in code behind:
private void Tab3_2Data_OnLoaded(object sender, RoutedEventArgs e)
{
mp = this.Ancestors().OfType<MainPage>().FirstOrDefault();
//mp.ShowMessage("test", OperationStatus.Green);
}
which uses the VisualTreeEnumeration helper class referenced in link above.
public static class VisualTreeEnumeration
{
public static IEnumerable<DependencyObject> Descendents(this DependencyObject root, int depth)
{
int count = VisualTreeHelper.GetChildrenCount(root);
for (int i = 0; i < count; i++)
{
var child = VisualTreeHelper.GetChild(root, i);
yield return child;
if (depth > 0)
{
foreach (var descendent in Descendents(child, --depth))
yield return descendent;
}
}
}
public static IEnumerable<DependencyObject> Descendents(this DependencyObject root)
{
return Descendents(root, Int32.MaxValue);
}
public static IEnumerable<DependencyObject> Ancestors(this DependencyObject root)
{
DependencyObject current = VisualTreeHelper.GetParent(root);
while (current != null)
{
yield return current;
current = VisualTreeHelper.GetParent(current);
}
}
}
I believe the parent will only be available when the control is loaded. You can try to run this logic in a handler for the UserControl.Loaded event.
In addition, as the control is child of a TabItem, it will only be loaded when the TabItem is visible.

Close a Window from Another In Wpf

If two Window is opened mainly A and B, how to close Window A using code that written on Window B.
Your best bet would be to create a property on Window B that you pass the creating Window to. Something like this. I have a Window named MainWindow and a second Window named Window2.
Main Window
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
Window2 secondForm;
public MainWindow()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
secondForm = new Window2();
secondForm.setCreatingForm =this;
secondForm.Show();
}
}
}
Window2
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for Window2.xaml
/// </summary>
public partial class Window2 : Window
{
Window creatingForm;
public Window2()
{
InitializeComponent();
}
public Window setCreatingForm
{
get { return creatingForm; }
set { creatingForm = value; }
}
private void button1_Click(object sender, RoutedEventArgs e)
{
if (creatingForm != null)
creatingForm.Close();
}
}
}
In respose to your comment, closing a window that was created by another form is as easy as calling the Close Method of the created Form:
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
Window2 secondForm;
public MainWindow()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
if (secondForm == null)
{
secondForm = new Window2();
secondForm.Show();
}
else
secondForm.Activate();
}
private void button2_Click(object sender, RoutedEventArgs e)
{
if (secondForm != null)
{
secondForm.Close();
secondForm = new Window2();
//How ever you are passing information to the secondWindow
secondForm.Show();
}
}
}
}
Here is a way to close any window from any other window. You can modify it to work with multiple instances by giving your windows some unique identifier and then just searching for that in the foreach loop.
public static class Helper
{
public static void CloseWindowOfWhichThereIsOnlyOne<T>()
{
Assembly currentAssembly = Assembly.GetExecutingAssembly();
foreach (Window w in Application.Current.Windows)
{
if (w.GetType().Assembly == currentAssembly && w is T)
{
w.Close();
break;
}
}
}
}
Or with a unique identifier "fudge":
public static void CloseWIndowUsingIdentifier(string windowTag)
{
Assembly currentAssembly = Assembly.GetExecutingAssembly();
foreach (Window w in Application.Current.Windows)
{
if (w.GetType().Assembly == currentAssembly && w.Tag.Equals(windowTag))
{
w.Close();
break;
}
}
}
I like this better than the suggested solution because you don't need to mess with your windows, other than to give them unique tags. I've only been using this for small projects where there is no risk of things not being unique, I'm not going to lose track of 10-12 windows!
The other suggested solution is a little silly (I don't have 50 karma to comment on it) as you could just call win.close() if you already had a reference to the object...
it is very simple make one public class and method like this
class Helper
{
public static void CloseWindow(Window x)
{
Assembly currentAssembly = Assembly.GetExecutingAssembly();
// int count = Application.Current.Windows;
foreach (Window w in Application.Current.Windows)
{
//Form f = Application.OpenForms[i];
if (w.GetType().Assembly == currentAssembly && w==x)
{
w.Close();
}
}
}
}
now call this function from where you want close window like this .
Helper.CloseWindow(win);//win is object of window which you want to close.
hope this helps.
foreach (Window w in Application.Current.Windows)
{
if (w.Name != "Main_Window_wind" )
{
w.Visibility = System.Windows.Visibility.Hidden;
}
}
//name is the x:Name="Main_Window_wind" in xaml
You can close now as hiden all windows without closing the named Main_Window_wind , you can add another window to be not closed with this in if: w.Name != "Main_Window_wind" && w.Name != "AnyOther_Window_wind" &&...
a quicker way is this:
for (int intCounter = App.Current.Windows.Count - 1; intCounter > -1; intCounter--)
{
if (App.Current.Windows[intCounter].Name != "Main_Window_wind")
App.Current.Windows[intCounter].Visibility = System.Windows.Visibility.Hidden;
}

Updating UI from a background thread which is called in a loop in main UI when the thread finishes

I have a WinForms application that is calling a business class method that performs some heavy duty action taking about 5 seconds for each call. The main form calls this method in a loop. This loop can run from 10 times to maybe up to 10 thousand times.
The WinForms application sends a parameter to the business class and has an area to display the time taken for each method call and what the value returned by the method. How do I inform my main window and update a text area in the main winform with what the method has returned for each call?
Currently the data comes all at once after all the threads have finished. Is there a way to update the UI for all the iterations of the loop once the each call is done? I don't mind if it is done sequentially also.
The FORM
HeavyDutyClass hd;
public Form1()
{
InitializeComponent();
hd = new HeavyDutyClass();
}
//BUTTON CLICK
private void Start_Click(object sender, EventArgs e)
{
int filecount = 5000; //BAD - opening 5000 threads! Any other approach?
hd.FileProcessed += new EventHandler(hd_FileProcessed);
var threads = new Thread[filecount];
for (int i = 0; i < filecount; i++)
{
threads[i] = new Thread(() => { hd.LongRunningMethod(); });
threads[i].Start();
}
}
//BUSINESS CLASS EVENT THAT FIRES WHEN BUSINESS METHOD COMPELTES
void hd_FileProcessed(object sender, EventArgs e)
{
if (dgv.InvokeRequired)
{
dgv.Invoke((MethodInvoker)delegate { UpdateGrid(); });
}
}
private void UpdateGrid()
{
dgv.Rows.Add(1);
int i = dgv.Rows.Count;
dgv.Rows [ i-1].Selected = true;
dgv.FirstDisplayedScrollingRowIndex = i - 1;
}
The business HeavyDuty class
public event EventHandler FileProcessed;
public HeavyDutyClass()
{
}
protected virtual void OnMyEvent(EventArgs e)
{
if (FileProcessed != null)
{
FileProcessed(this, e);
}
}
public bool LongRunningMethod()
{
for (double i = 0; i < 199990000; i++)
{
//time consuming loop
}
OnMyEvent(EventArgs.Empty);
return true;
}
Add a Winforms Project, Drop a Label Control on the Form , Copy-Paste this code and Hit F5
[EDIT]: Updated with the business class comment from the user
NB: My form class is named Form3. You may have to change your Program.cs or vice-versa.
using System.ComponentModel;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public class BusinessClass
{
public int MyFunction(int input)
{
return input+10;
}
}
public partial class Form3 : Form
{
private BackgroundWorker _worker;
BusinessClass _biz = new BusinessClass();
public Form3()
{
InitializeComponent();
InitWorker();
}
private void InitWorker()
{
if (_worker != null)
{
_worker.Dispose();
}
_worker = new BackgroundWorker
{
WorkerReportsProgress = true,
WorkerSupportsCancellation = true
};
_worker.DoWork += DoWork;
_worker.RunWorkerCompleted += RunWorkerCompleted;
_worker.ProgressChanged += ProgressChanged;
_worker.RunWorkerAsync();
}
void DoWork(object sender, DoWorkEventArgs e)
{
int highestPercentageReached = 0;
if (_worker.CancellationPending)
{
e.Cancel = true;
}
else
{
double i = 0.0d;
int junk = 0;
for (i = 0; i <= 199990000; i++)
{
int result = _biz.MyFunction(junk);
junk++;
// Report progress as a percentage of the total task.
var percentComplete = (int)(i / 199990000 * 100);
if (percentComplete > highestPercentageReached)
{
highestPercentageReached = percentComplete;
// note I can pass the business class result also and display the same in the LABEL
_worker.ReportProgress(percentComplete, result);
_worker.CancelAsync();
}
}
}
}
void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
{
// Display some message to the user that task has been
// cancelled
}
else if (e.Error != null)
{
// Do something with the error
}
}
void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
label1.Text = string.Format("Result {0}: Percent {1}",e.UserState, e.ProgressPercentage);
}
}
}
With this you can achieve Cancel functionality also very easily.
Observe that during initialisation, I set the WorkerSupportsCancellation = true & then I check for _worker.CancellationPending in the DoWork. So, if you want to cancel the process by a Cancel Button click, then you will write this code in the button handler- _worker.CancelAsync();

The calling thread cannot access this object because a different thread owns it

I am getting the exception "The calling thread cannot access this object because a different thread owns it" inspite of using Dispatcher.Invoke.
Below is the code: _btnImage1 is an instance of ImageButton declared in xaml of LaneImageReview. Note that I used Dispatcher in the RefreshLiveVESImage method below.
public partial class LaneImageReview : Page
{
private void RefreshLiveVESImages(VESImagePackageInfo p_VesImageInfo)
{
this._btnImage1.RefreshLiveVESImage(p_VesImageInfo);
}
}
public class ImageButton : Button
{
public void RefreshLiveVESImage(VESImagePackageInfo p_VesImageInfo)
{
BitmapImage bitmap = null;
try
{
//load background if not photo available
//if (p_Image == null)
//{
// _imgPhoto.Source = null;
//}
//else
//{
foreach (VESCameraInfo camInfo in p_VesImageInfo.VESCameras)
{
if (camInfo.CameraImageSets[0].FullImage != null)
{
bitmap = DVASViewController.GetBitmapImageFromByteArray(camInfo.CameraImageSets[0].FullImage.VESImage);
this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, new Action<BitmapImage>(SetImageSource), bitmap);
break;
}
}
//}
}
catch (Exception ex)
{
SecurityController.CatchException(ex);
}
finally
{
}
}
private void SetImageSource(BitmapImage p_Image)
{
this.imgFrontLeft.Source = p_Image;
}
}
Thanks.
you can try something like
Application.Current.Dispatcher.Invoke((ThreadStart)delegate
{
DoWork();
});

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