I realized an interface in WPF Page and I want to call ShowInputAsync in the MainWindow, which is where the Page is. In order to do that, I raise event in Page and block function with AutoResetEvent:
public AutoResetEvent OnMessageReceived;
public void MessageReceived(object sender, PageReturnMessageEventArgs e)
{
try
{
if (e.ToString() == "Cancel" || string.IsNullOrEmpty(e.ToString()))
{
throw new Exception("Exception of parsing of hours");
}
}
catch (Exception ex)
{
// log it
}
this.OnMessageReceived.Set();
}
private void Page_OnNextPageClick(object sender, EventArgs e)
{
// ...
MessageShow("Additional information", "How much time will this SuperProcess take?", "HOURS");
OnMessageReceived.WaitOne();
OnMessageReceived.Reset();
// ...
}
If I try to show ShowInputAsync from any function in MainWindow it works:
MetroDialogSettings s = new MetroDialogSettings();
s.AffirmativeButtonText = #"Create";
s.NegativeButtonText = #"Cancel";
s.AnimateShow = true;
var result = await this.ShowInputAsync("Test", "TestMessage", s);
if (result == null)
{ return; }
If I try to show this dialog from event handler, it doesn't work. After line
var result = await this.ShowInputAsync("Test", "TestMessage", s);
code returns to Page without any exception, executes line
OnMessageReceived.WaitOne();
and shows the window without any dialog, all Controls are showing and enabled, but I can't press them.
I also tried to put the dialog in a separate function, and call it with/without await, nothing changes.
To use AutoResetEvent after calling the Dialog to block further execution of code, also didn't help.
private AutoResetEvent OnMessageReturning;
var result = await this.ShowInputAsync(e.Title, e.Message, s);
OnMessageReturning.WaitOne();
Also tried to call the separate function in this way without result:
CancellationToken token;
TaskScheduler uiSched = TaskScheduler.FromCurrentSynchronizationContext();
await Task.Factory.StartNew(SeparateFunction, token, TaskCreationOptions.None, uiSched);
How can I call ShowInputAsync correctly in event handler? Or how can I call ShowInputAsync from Page in MainWindow?
P.S. There is TabControl in MainWindow, Page is placed in Frame of one TabItem
Using:
MahApps.Metro v1.4.1 (NuGet package)
Windows OS 7
Visual Studio Express 2015
.NET Framework 4.5
UPD: Easy sample is https://github.com/awg21/MahAppsShowInputAsyncFromPage
I found a solution here I'm using:
TryFindParent<> is an extension method defined in MahApps.Metro.Controls.TreeHelper, and ShowMessageAsync<> is defined in MahApps.Metro.Controls.Dialogs.DialogManager
Related
I have a WebBrowser control on a form, but for the most part it remains hidden from the user. It is there to handle a series of login and other tasks. I have to use this control because there is a ton of Javascript that handles the login. (i.e., I can't just switch to a WebClient object.)
After hopping around a bit, we end up wanting to download a PDF file. But instead of downloading, the file is displayed within the webBrowser control, which the user can not see.
How can I download the PDF instead of having it load in the browser control?
Add a SaveFileDialog control to your form, then add the following code on your WebBrowser's Navigating event:
private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
{
if (e.Url.Segments[e.Url.Segments.Length - 1].EndsWith(".pdf"))
{
e.Cancel = true;
string filepath = null;
saveFileDialog1.FileName = e.Url.Segments[e.Url.Segments.Length - 1];
if (saveFileDialog1.ShowDialog() == DialogResult.OK)
{
filepath = saveFileDialog1.FileName;
WebClient client = new WebClient();
client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);
client.DownloadFileAsync(e.Url, filepath);
}
}
}
//Callback function
void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
MessageBox.Show("File downloaded");
}
Source: http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/d338a2c8-96df-4cb0-b8be-c5fbdd7c9202
The solution I ended up using:
I did everything else as-needed to get the URL where it needed to go. Knowing that all of the login information, required settings, viewstates, etc. were stored in the cookies, I was finally able to grab the file using a hybrid of the web control to navigate then the WebClient object to actually snag the file bytes.
public byte[] GetPDF(string keyValue)
{
DoLogin();
// Ask the source to generate the PDF. The PDF doesn't
// exist on the server until you have visited this page
// at least ONCE. The PDF exists for five minutes after
// the visit, so you have to snag it pretty quick.
LoadUrl(string.Format(
"https://www.theMagicSource.com/getimage.do?&key={0}&imageoutputformat=PDF",
keyValue));
// Now that we're logged in (not shown here), and
// (hopefully) at the right location, snag the cookies.
// We can use them to download the PDF directly.
string cookies = GetCookies();
byte[] fileBytes = null;
try
{
// We are fully logged in, and by now, the PDF should
// be generated. GO GET IT!
WebClient wc = new WebClient();
wc.Headers.Add("Cookie: " + cookies);
string tmpFile = Path.GetTempFileName();
wc.DownloadFile(string.Format(
"https://www.theMagicSource.com/document?id={0}_final.PDF",
keyValue), tmpFile);
fileBytes = File.ReadAllBytes(tmpFile);
File.Delete(tmpFile);
}
catch (Exception ex)
{
// If we can't get the PDF here, then just ignore the error and return null.
throw new WebScrapePDFException(
"Could not find the specified file.", ex);
}
return fileBytes;
}
private void LoadUrl(string url)
{
InternalBrowser.Navigate(url);
// Let the browser control do what it needs to do to start
// processing the page.
Thread.Sleep(100);
// If EITHER we can't continue OR
// the web browser has not been idle for 10 consecutive seconds yet,
// then wait some more.
// ...
// ... Some stuff here to make sure the page is fully loaded and ready.
// ... Removed to reduce complexity, but you get the idea.
// ...
}
private string GetCookies()
{
if (InternalBrowser.InvokeRequired)
{
return (string)InternalBrowser.Invoke(new Func<string>(() => GetCookies()));
}
else
{
return InternalBrowser.Document.Cookie;
}
}
bool documentCompleted = false;
string getInnerText(string url)
{
documentCompleted = false;
web.Navigate(url);
while (!documentCompleted)
Application.DoEvents();
return web.Document.Body.InnerText;
}
private void web_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
documentCompleted = true;
}
I need in wpf app check messages on server. I have own method which load messages on server-LoadRp().
I would like to create some kind of listener which would check, every 3 seconds whether on the server are not new messages.
I call method for loading messages on dispatcher timer tick event, it is suitable? Any another solution. It’s possible call timer in another thread in wpf?
Code is here:
public MessangerWindow(PokecCommands pokecCmd)
{
InitializeComponent();
PokecCmd = pokecCmd;
_friendsData = PokecCmd.LoadFriends();
friendsListBox.DataContext = _friendsData;
_dispatcherTimer = new DispatcherTimer();
_dispatcherTimer.Tick+=new EventHandler(DispatcherTimer_Tick);
_dispatcherTimer.Interval = new TimeSpan(0,0,3);
_dispatcherTimer.Start();
}
private void DispatcherTimer_Tick(object sender, EventArgs eventArgs)
{
try
{
//try load new message from sever
RP message = PokecCmd.LoadRp();
//arived message
if (message != null)
{
//exist window
if (_chatWindows.ContainsKey(message.Nick))
{
_chatWindows[message.Nick].Show();
}
{
//create new Window
var chatWindow = new ChatWindow(PokecCmd, message);
_chatWindows.Add(message.Nick, chatWindow);
chatWindow.Show();
}
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
}
}
What is suitable to use:
Dispatcher with no background threads
Dispatcher with background threads
Multiple Threads
If you are ok with locking up your UI for the time it takes to check on the server, using a DispatcherTimer the way you are doing it will work fine.
If checking for new messages could take more than a few milliseconds and you want your UI to be responsive while it checks, you should use multiple threads. In that case, once the new data had arrived you would use Dispatcher.Invoke to display it.
Your code in the thread that checks for messages might look like this:
//try load new message from sever
RP message = PokecCmd.LoadRp();
//arived message
if( message != null )
Dispatcher.Invoke(DispatcherPriority.Send, new Action(() =>
{
//exist window
if (_chatWindows.ContainsKey(message.Nick))
{
_chatWindows[message.Nick].Show();
}
{
//create new Window
var chatWindow = new ChatWindow(PokecCmd, message);
_chatWindows.Add(message.Nick, chatWindow);
chatWindow.Show();
}
}
);
I've made a rather complex Silverlight 4 out-of-browser application. One of my main view models adds an event handler to the Application.Current.MainWindow.Closing event.
This works fine when the application is initially run. It is able to cancel the close operation.
However, sometimes after performing operations like showing and closing a ChildWindow, the MainWindow's Closing event is no longer calling my handler.
In the debugger, I added a watch to the MainWindow's underlying closing event delegate. It's not null before showing the ChildWindow. Then sometimes after the ChildWindow is closed the delegate is null. This is explains why my handler is not called any more. But why is this delegate getting nulled? And why is it only happening occasionally?
My application is not unbinding my event handler at any point.
This is the delegate I'm watching:
System.Windows.Application.Current.MainWindow.m_closingEvent
Other stuff: I'm using Caliburn Micro
I had the exact same problem. We have a large silverlight application running OOB.
For some reason the m_ClosingEvent was nulled after running for a while. I have not been able to find the cause of this issue but I think it may have something to do with us changing the root visual or all the child windows we show.
I´m using a class ApplicationWrapper.
public class ApplicationWrapper : IApplicationWrapper
{
public void Initialize()
{
HookCloseEvent(true);
}
private void HookCloseEvent(bool hook)
{
if (hook && IsRunningOutOfBrowser)
{
Application.Current.MainWindow.Closing += OnClosing;
}
else
{
if (IsRunningOutOfBrowser)
{
Application.Current.MainWindow.Closing -= OnClosing;
}
}
}
private void OnClosing(object sender, ClosingEventArgs e)
{
InvokeClosing(e);
}
... etc..
}
And the InvokeClosing method was never called. But when I changed it to
public class ApplicationWrapper : IApplicationWrapper
{
private Window _mainWindow;
public void Initialize()
{
if(IsRunningOutOfBrowser)
{
_mainWindow = Application.Current.MainWindow;
}
HookCloseEvent(true);
}
private void HookCloseEvent(bool hook)
{
if (hook && IsRunningOutOfBrowser)
{
_mainWindow.Closing += OnClosing;
}
else
{
if (IsRunningOutOfBrowser)
{
_mainWindow.Closing -= OnClosing;
}
}
}
private void OnClosing(object sender, ClosingEventArgs e)
{
InvokeClosing(e);
}
... etc...
}
The m_ClosingEvent isn´t nulled.
So, try to just store the "initial" MainWindow in a field and check if that solves your problem.
Instead of hooking to the event, why not register a service instead? Create a class that implements IApplicationService and IApplicationLifetimeAware. The latter gives you an "onexiting" and "onexited" pair of events. You place the service in the application by pointing to it in a section called in your App.xaml. I've used this for many projects and never had an issue with the exiting methods not being called.
Ok, after pulling out my hair and many false starts I finally found the answer - it seems to be a known bug with the Closing event, OOB and ChildWindows open/closes...
The trick is to store a static reference to the Main Window:
public MainPage()
{
InitializeComponent();
Loaded += MainPage_Loaded;
}
private void MainPage_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
//you have to store this to work around the bug
//http://forums.silverlight.net/forums/p/185664/424174.aspx
_mainWindow = App.GetApp.MainWindow;
App.GetApp.MainWindow.Closing += (s, e1) =>
{
if (UIUtilities.ShowMessage("Would you like to exit AMT Mobile?", "Exit Application", MessageBoxButton.OKCancel) != MessageBoxResult.OK)
{
e1.Cancel = true;
}
};
}
Well I'm using a Window as my custom message box with a couple of controls which are displayed/populated with text depending on which constructor is called.
I have a defined event, which is subscribed to via the original class, this fires once the button has been clicked.
However I can't see how to use this effectively, preferably I'd like to return a bool whether Yes or No was clicked, however obviously my code will carry on executing, hence the method which is subscibed to the button click. Below is some example code to make the issue clearer.
Message Box Window
public partial class CustomMessageBox : Window
{
public delegate void MessageBoxHandler(object sender, EventArgs e);
public event MessageBoxHandler MessageBoxEvent;
public CustomMessageBox()
{
InitializeComponent();
}
public CustomMessageBox(string message)
{
InitializeComponent();
this.txtdescription.Text = message;
}
public CustomMessageBox(string message, string title, string firstBtnText)
{
InitializeComponent();
this.lbltitle.Content = title;
this.txtdescription.Text = message;
this.btnstart.Content = firstBtnText;
}
}
public static class MessageBoxButtonClick
{
public static bool Yes { get; set; }
public static bool No { get; set; }
public static bool Cancel { get; set; }
}
Window Which Instantiates the MessageBox Window
private void StartProcess_Click(object sender, System.Windows.RoutedEventArgs e)
{
foreach (var result in results)
{
if(result.ToBeProcessed)
_validResults.Add(new ToBeProcessed(result.Uri, result.Links));
}
_msgbox = new CustomMessageBox("Each Uri's backlinks will now be collected from Yahoo and filtered, finally each link will be visited and parsed. The operation is undertaken in this manner to avoid temporary IP Blocks from Yahoo's servers.", "Just a FYI", "OK");
_msgbox.MessageBoxEvent += (MessageBoxHandler);
if (_msgBoxProceed)
{
_msgbox.Close();
Yahoo yahoo = new Yahoo();
yahoo.Status.Sending += (StatusChange);
//What I'd like to happen here is the code simply stop, like it does when calling a messagebox is winforms
//e.g.
// if(ProceedClicked == true)
// do stuff
// yahoo.ScrapeYahoo(_validResults[Cycle].Uri, _validResults[Cycle].LinkNumber);
//Cycle++;
}
else
{
_msgbox.Close();
}
}
private void MessageBoxHandler(object sender, EventArgs e)
{
if (MessageBoxButtonClick.Yes)
{
ProceedClicked = true;
}
else
{
ProceedClicked = false;
}
}
Hopefully that makes it clear enough, I can't put any execution code ie call a certain method due to using it multiple times throughout my application.
Very hard to understand what the problem exactly is. Also the code you wrote here, doesn't seemt to have any calls, that would actually show the CustomMessageBoxWindow.
But I'll take a stab at this...
First of all, am I right in guessing that in your main Window you want your code to wait at if(_msgBoxProceed) until the user actually presses a button in your CustomMessageBoxWindow (currently it just shows the message box and continues executing the next statements)?
If so then I'm guessing you are showing your message box window with the Show() method. Use ShowDialog() instead. That will cause code execution to stop, until the message box gets closed.
If you don't want to use a modal dialog then there are two options. Either use thread syncrhonization objects (eg AutoResetEvent) or set up a new event for when the message box closes and continue your code execution in the closed event handler (in StartProcess_Click the last line would be a call to _msgBox.Show() and everything from if(_msgBoxProceed) would be in the closed event handler).
Firstly, I know I should be using proper Threading techniques (Threadpool, BeginInvoke, etc.) to accomplish this, but thats a bit over my head currently and will call for some time to read over material and understand it (if you have any URL references for my scenario, please feel free to post it).
In the interim I am using the backgroundWorker to pull a very large resultset and populate a DatagridView with it. I successfully create a SortableBindingList<TEntities> in my DoWork event and pass that out in the result. And in the RunWorkerCompleted event, I cast and bind that SortableBindingList<TEntities> to my Grid. My 2 main areas of concern are as follows:
1) Access to private variables.
I want to pass one of two parameters List<long> into my DoWork event, but run a different query depending on which list was passed to it. I can get around this by declaring a class-level private boolean variable that acts a flag of sorts. This seems silly to ask, but in my DoWork, am I allowed to access that private variable and route the query accordingly? (I've tested this and it does work, without any errors popping up)
private bool SearchEngaged = false;
private void bgw_DoWork(object sender, DoWorkEventArgs e) {
BackgroundWorker worker = sender as BackgroundWorker;
e.Result = GetTasks((List<long>)e.Argument, worker, e);
}
SortableBindingList<Task> GetTasks(List<long> argsList, BackgroundWorker worker, DoWorkEventArgs e) {
SortableBindingList<Task> sbl = null;
if (worker.CancellationPending) {
e.Cancel = true;
}
else {
if (SearchEngaged) {
sbl = DU.GetTasksByKeys(argsList);
}
else {
sbl = DU.GetTasksByDivision(argsList);
}
}
return sbl;
}
2) UI Thread freezes on beginning of RunWorkerCompleted.
Ok, I know that my UI is responsive during the DoWork event, 'cos it takes +/- 2seconds to run and return my SortableBindingList<Task> if I don't bind the List to the Grid, but merely populate it. However my UI freezes when I bind that to the Grid, which I am doing in the RunWorkerCompleted event. Keep in mind that my Grid has 4 image columns which I handle in CellFormatting. This process takes an additional 8 seconds to accomplish, during which, my UI is completely non-interactive. Im aware of the cross-thread implications of doing so, but is there any way I can accomplish the Grid population and formatting either in the background or without causing my UI to freeze? RunWorkeCompleted looks like so:
private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) {
if (e.Cancelled) {
lblStatus.Text = "Operation was cancelled";
}
else if (e.Error != null) {
lblStatus.Text = string.Format("Error: {0}", e.Error.Message);
}
else {
SortableBindingList<Task> sblResult = (SortableBindingList<Task>)e.Result;
dgv.DataSource = sblResult;
dgv.Enabled = true;
TimeSpan Duration = DateTime.Now.TimeOfDay - DurationStart;
lblStatus.Text = string.Format("Displaying {0} {1}", sblResult.Count, "Tasks");
lblDuration.Visible = true;
lblDuration.Text = string.Format("(data retrieved in {0} seconds)", Math.Round(Duration.TotalSeconds, 2));
cmdAsyncCancel.Visible = false;
tmrProgressUpdate.Stop();
tmrProgressUpdate.Enabled = false;
pbStatus.Visible = false;
}
}
Sorry for the lengthy query, but I will truly appreciate your responses! thank you!
Your code appears to be doing exactly the right thing.
As for the 8 seconds that it takes for the UI thread to update the screen, there's not much you can do about that. See my answer to this question.
To optimise the UI part, you could try calling SuspendLayout and ResumeLayout on the grid or its containing panel.
You could also look at trying to reduce the amount of processing that is done during the data binding. For example:
Calculations done in the grid could be moved into the data model (thereby doing them in the worker thread).
If the grid auto-calculates its columns based on the data model, then try hard-coding them instead.
EDIT: Page the data in the Business Layer and make the grid only show a small number of rows at a time.
I think the easiest solution for your problem is setting the datasource of your grid in DoWork instead of RunWorkerCompleted using Dispatcher.BeginInvoke which you have mentioned yourself. Something like this:
private bool SearchEngaged = false;
private void bgw_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
SortableBindingList<Task> sblResult = GetTasks((List<long>)e.Argument, worker, e);
BeginInvoke((Action<object>)(o => dataGridView1.DataSource = o), sblResult);
}
private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled) {
lblStatus.Text = "Operation was cancelled";
}
else if (e.Error != null) {
lblStatus.Text = string.Format("Error: {0}", e.Error.Message);
}
else
{
dgv.Enabled = true;
TimeSpan Duration = DateTime.Now.TimeOfDay - DurationStart;
lblStatus.Text = string.Format("Displaying {0} {1}", sblResult.Count, "Tasks");
lblDuration.Visible = true;
lblDuration.Text = string.Format("(data retrieved in {0} seconds)", Math.Round(Duration.TotalSeconds, 2));
cmdAsyncCancel.Visible = false;
tmrProgressUpdate.Stop();
tmrProgressUpdate.Enabled = false;
pbStatus.Visible = false;
}
}
As far as the private variable issue is concerned, I don't think it will be of any problem in your case. In case you are changing it using some UI event, just mark the private field as volatile. The documentation of the volatile keyword can be found here:
http://msdn.microsoft.com/en-us/library/x13ttww7.aspx