In my application there are only 2 windows — win_a & win_b, on each of these windows there is button that call another window, e.g. click on btn1 of win_a will call win_b, click on btn2 of win_b will show win_a.
Desired behaviour:
1. Only one instance of object is premitted at the same time, e.g. situation, where 2 instances of win_a running at the same time is not permitted.
When you click on button that calls windows that already exist this action will only change a focus to needed window.
If you call a window that previously had been created, but after this has been closed this action will create a new instance of this window. E.g. there are 2 running windows. you close one of them and after try to call this window back, so related button will create it.
How to write it in WPF (XAML + C#). For the moment I wrote a version that can create a lot of instances of the same window (no number of instances control implemented), but I want to see only one instance of the same window, as we can see it in a lot of applications.
Example of my code:
Window win = new Window();
win.Show();
Thanks.
first you need 2 references on each other window. on button click
you need to check one reference.
say in win_a
//win_b is a member on Windows_a class
if(_win_b.IsVisible())
{
// set focus on it
}
else
{
//show win_b
}
make the same for windows_b
I would suggest a different approach:
make a singleton class, that holds a list of tuples List>
when creating windows you can check if the window is in the collection or not.
if the collection holds a window you can set it activ win.Activate(),
else you can create it and add a reference to the collection list.add(tuple(win,"windowA"))
3.finally on the windows that you can add to the collection, on closing you need to remove the window from the singletons list, you can do this handling the Close event of the window
i don't have the code i wrote here, but i hope it helps.
Related
I have a selection of TextBoxes that a user fills in when they wish to note that they have had contact with another person. Most of the TextBoxes are imply filled in by typing into them. However, for one of them I would like the user to be able to select from a list of People that appears when they click on a button.
This is where I am having problems. So far I have just made a DataGrid appear and handled it's SelectionChanged method to fill in the TextBoxes text property. This has worked fine, however now there is not enough space on the current page to show an entire DataGrid with all the people they can select from.
I've decided to show the People in a separate, smaller Window that appears when the user clicks a Button. The issue I have is that when the user selects the Person they wish to mark the contact for in the new Window, I have no idea how I can notify the original Window that a Person has been selected, close the new smaller Window and fill in the appropriate TextBox on the original Window.
What would be the most intuitive way to fill in the TextBox on the original Window, based on the selection on the Window that opens?
I would use delegates,which call a function of the original window and parse the changed variable with it. So you know when the user clicked something and you can directly react to this "event".
Link:
https://msdn.microsoft.com/en-us/library/ms173171.aspx
If you use a framework like Galasoft's MVVM Light (http://www.galasoft.ch/), they have a messenger system just for this purpose. It allows you to "broadcast" messages that can be "received" by any other part of the application
This is when considering using Domain, Model, Presentation (Winforms/WPF version of MVC formatting) to do your app.
You can have each form as its own class, well they are their own class. Create each form class but add some public members to it if the controls are private. Have them have "get" properties only and to return the values of whatever controls or variables are in that form. Your main form will be the controlling form. All forms will be handled by the main form so when you open it, it is a class the main form can access.
Now, if I remember (been doing more MVC and not any Winforms lately) I believe if you use the ShowDialog() method it will freeze the main thread so when you close out the main form you can continue and read in public members you have in your forms class you opened. Synchronous I believe it runs as. If you use just Show() the thread will keep on trucking, asynchronous. With asynchronous you may then have to use a main form in your startup code so there is always a window there but subscribe to the close event of your forms and have a method that can grab those public members out. Be sure to instantiate the extra forms at the root of the main class so it doesn't fall out of scope when it exists the method that calls it. You may even be able to make the method that calls is a async call and have an await before the command that runs the Show method on the form.
Summary, treat each form as its own class but add public members that can read the values from the controls and/or variables you want. Read that data from the class when it closes via an event or synchronously when the thread closes out from the form closing. The form closing doesn't discard the object, just the visualization of the form.
Oh, if you are passing info from the main form to a child for you are opening, either add a constructor for that form class that takes your input as a model or values to fill in the appropriate variables or forms before showing it or create a public property you can put your values you want to send in before showing the class.
Remember, everything is a class, once you look at it as such and treat it as such, the answer will come. :-)
I should warn, I am a long winded explainer.
At work putting all this down from memory so some errors may exist. Let me know if there are.
I think the problem is to access the controls of the main window, isn`t it?
You can define an event of changing user`s choise and access MainWindow control by using the following construction:
((MainWindow)Application.Current.MainWindow).MyTextBox
Still getting used to WPF from a win forms programmer. I have multiple forms in an application that can be accessed from multiple locations, so I need to keep the forms "global" as I'm not sure of a better terminology.
For instance "Details" can be opened from a "Main Menu" but can also be opened from a grid in "Search", I'd like the details returned from the search to be displayed in the "Details" page even if it was pre-opened from the main menu.
I've come across Application.Current.Properties and have started storing a few forms in it but it just feels plain wrong to set:
Vehicle vehicleForm = new Vehicle();
Application.Current.Properties["frmVehicle"] = vehicleForm;
And then to access it:
if (Application.Current.Properties["frmVehicle"] == null)
Application.Current.Properties["frmVehicle"] = new frmVehicle();
Vehicle vehicleFrm = (Vehicle)Application.Current.Properties["frmVehicle"];
vehicleFrm.Show();
vehicleFrm.Activate();
I have just discovered Application.Current.Windows as well which has thrown me a little.
What is the most efficient/industry standard way of dealing with form like this?
I would just check whether Application.Current.Windows contains an instance of your window. If so then you give it focus, if not then you create an instance.
I'm not sure if I understand how are you opening the window correctly. But if all you want to do is to have one instance of the window through the whole run time of the application, you can use the Singleton pattern. Basically, the window class has a static property that holds the only instance.
If you don't need to keep any state in the window, you can just create new instance of it every time you want to show it.
Edit for those who say to use tab control
I would love to use a tab control; yet i have no idea how to go about linking the tab control up from the main form. I would assume that I would have to do something like this:
Create Form with a blank TabControl on it, no pages created.
Create a CustomuserControl (Add -> user Control), with my controls on it.
When a new chat comes in, create a tab control Item, Tab Control Page, add the Custom Control to the Tab Control Page. Add the tab control handle to the hash table, so that when new messages come in, they can be referenced in the proper control.
But, i am so not sure how to do this. For example, I know that I can create custom events inside of the User Control, so that, for example, if each control has a 'bold' button, i can each page that has that control on it, to actually USE the button.
Yet i also need to register message callbacks, so that I can use a MessageGrabber to send data to it, and tha'ts not assigned inside of the UserControl, that's assigned programatically when a new window comes in; but since I have no controls to reference, i can't assign.
KISS Philosophy
Wouldn't it be easier to just create the form, like i do now, and then just dock that form within a window or something? So that, in essence, it's still creating the form, but it's also a separate window?
Original Question
Okay, so i'm stumped (which isn't that big of a surprise when it comes to complex C# logic lol)! What i'm trying to do is the following:
Goal: Setup tabbed chatting for new chat application.
Completed: Open new window whenever a chat message is received, or a user requests a new chat from the roster. This is working perfectly, and opens only a window when the user doesn't already have the chat open. Nice and happy there.
Problem: I dont want windows. Well, i do want A window, but, i do not want tons of separate windows. For example, our Customer Service team may have about 10 active IM windows going at one time, i do not want them to have to have 10 windows tiled there lol. I'd rather they have a single Private IM window, and all 10 tabs docked within the window.
Logic: This is my logic here, which may be flawed, i do apologize:
OnMessage: Open new chat window if one doesn't already exist; if one exists, open it as a tab within the current chat window.
SendMessage: ^^ ditto ^^
Code Examples:
if (!Util.ChatForms.ContainsKey(msg.From.Bare))
{
RosterNode rn = rosterControl1.GetRosterItem(msg.From);
string nick = msg.From.Bare;
if (rn != null)
nick = rn.Text;
frmChat f = new frmChat(msg.From, xmpp, nick);
f.Show();
f.IncomingMessage(msg);
return;
}
Note on above: The Util. function just keeps tracks of what windows are opened inside of a hashtable, that way, when messages come in, they route to the proper window. That is added with the:
Util.ChatForms.Add(m_Jid.Bare.ToLower(), this);
Command in the frmChat() form.
Library in Use: agsxmpp from: http://www.ag-software.de/agsxmpp-sdk/download/
Problem:
How can i convert this code to open inside of tabs, instead of windows? Can someone please give me some ideas, and help with that. I just can't seem to wrap my head around that concept.
Use TabControl
I am using the Business Silverlight application. I have incorporated some MVVM into this and were off an running with it. We are using some telerik controls, mostly the ribbon control and the docking. We register all the telerik ribbon controls in the about.xaml.cs file, the method is DisplayUI - its here where we register the docking control then we register the ribbon after this. What happens is that when you click the ABOUT link it shows our first tab with buttons(perfect). when you click the HOME link next to the ABOUT link, we go back to the home page..but when you click the ABOUT link again it registers the controls again so we end up with two tabs that are the same.
Is there a way to check to see if this about.xaml.cs file has already been initialized? Im guessing that is has a handle on the first call in memory as I am able to see the first tabs rendering..
Thanks
here is the about code
public About()
{
InitializeComponent();
DisplayUI();
this.Title = ApplicationStrings.AboutPageTitle;
}
that display UI does all the work in registering the dockpanel and the ribbons. We'd like to not have the DisplayUI() called if this has already been rendered once.
If you do it by event handler can you unsubscribe from the event at the end of the method? Without seeing some code it's hard to work out what to change.
It's not the nicest way of doing it, but if this code needs to run once and only once then you could have a static boolean variable on the class set to false and when you call DisplayUI you check the value of this. If it's false you set it to true and run the method, and if it's true you just return.
I am writing a small class for driving integration testing of a win form application. The test driver class has access to the main Form and looks up the control that needs to be used by name, and uses it to drive the test. To find the control I am traversing the Control.Controls tree. However, I get stuck when I want to get to controls in a dialog window (a custom form shown as a dialog). How can I get hold of it?
You can get a reference to the currently active form by using the static Form.ActiveForm property.
Edit: If no Form has the focus, Form.ActiveForm will return null.
One way to get around this is to use the Application.OpenForms collection and retrieve the last item, witch will be the active Form when it is displayed using ShowDialog:
// using Linq:
var lastOpenedForm = Application.OpenForms.Cast<Form>().Last()
// or (without Linq):
var lastOpenedForm = Application.OpenForms[Application.OpenForms.Count - 1]
I'm not sure if you can access controls on a pre-built dialog box; they seem all packaged together. You may have more luck building a dialog box of your own that does what you want it to do. Then you can access the .Controls inside of it.
Correct me if i'm wrong, though, it sounds as if you are possibly attempting to access the controls on the dialog form when it's not quite possible to.
What I mean is, ShowDialog will "hold up" the thread that the form was created on and will not return control to the application (or, your test class) until ShowDialog has finished processing, in which case your user code would continue on its path.
Try accessing or manipulating the controls from a separate thread (in this case, refactor the test driver class to spawn a separate thread for each new form that must be displayed and tested).