I started re-grouping my forms with user controls and split containers on an existing application. Before I had a class called GlobalFunctions that had a method called ResetAllForms(). When I ran GlobalFunctions.ResetAllForms() from frmMain it would set all the properties in the form to the default values I wanted for them (disabled/enabled, visible or invisible.)
Before I was accessing them like formName.Textbox1.Enabled = True but now if I try to call them from the user control name like UserControlA.Textbox1.Enabled = True it gives me an error saying "Reference to a non-shared member requires an object reference". I know that means it was mean to instantiate a copy of the user control, but I am just dragging and dropping from the toolbox, so I don't know what its name is.
Apparently it is instating the user control in the back-end. I found it by using IntelliSense to find its name from the main form.
So inside my GlobalFunctions.ResetAllForms() method, I found it as frmMain.UserControlA1.Textbox1. So then I was able to set it like this;
frmMain.UserControlA1.Textbox1.Enabled = True
Apparently when it is instantiated in the back-end it just adds a one to the user control name.
Related
I'm trying to find solution for the following problem. I have a WPF app, I used mvvm and prism (most recent version 7) to build it. Here is the draft of the form/dialog I work on:
MainView has region - region1, I inject SubViewA into region1 based on what is selected in treeview. This view represents treeitem content. SubViewA itslef has region - region2, and another view - SubViewB is injected into region2 based on combobox selection.
I use INavigationAware to manage injection to the region.
So to inject view into region I use from MainViewModel the following:
_regionManager.RequestNavigate(regionName, viewName, callBack, parameters);
In the SubViewAViewModel I implement INavigationAware, and to reuse created views I check if view per treeitem was created. To do it I add into parameters a treeitemId and then I check this id in IsNavigationTarget method like this:
bool IsNavigationTarget(NavigationContext navigationContext)
{
// get id parameter from navigationContext.Parameters
// check if subviewA for treeitemId was already shown and return true,
// i use dictionary, where i store ids of all items that were selected in the past
// otherwise return false.
}
The same method I use when I want to inject SubViewB into region 2 of SubViewA. Mostly when user changes dropdown selection new SubViewB is injected.
Now my question is - if I use INavigationAware in SubViewBViewModel and when IsNavigationTarget always returns true - all is good. When I try to reuse views and again chose what to return true or false, then when I select second item in treeview I got an exception: "Region with the given name is already registered" - prism complains that region2 was already registered.
I know that I can have service and always populate data from the service when View is shown, and because of that I don't need to reuse views. But it's more academic question - what is the proper way to solve it?
P.S. I tried to register scoped region manager, but I was not successful, my problem is I don't know where is the best place to create new scoped manager and how to inject it into viewmodel. Parent's ViewModel is not good place to do it, because I have to expose view. If I try to use attached behavior, then it seems, region content is updated before behavior is invoked.
P.S.2 I found an example from pluralsight (by Brian Lagunas), where he creates two shells, but it differs from what I want to achieve. He creates new scope manager per window in the moment when window is created. And also if window itself will have the same structure as I showed above, it will fail too.
P.S.3 I watched recent streams from Brian Lagunas where he is writing outlook from scratch, his approach is based on behavior, he associates some view with dependent views, it works fine, but again in his example dependent views don't contain regions.
Thank you.
For those who are interested in details, you have to watch the following pluralsight courses: pluralsight.pxf.io/XVxR5 & pluralsight.pxf.io/B6X99. One is about multiple shells and another is about tabbed control, which is called 'Prism Problems & Solutions: Mastering TabControl' - this course helped me.
In short, the problem is about how to inject scope region in the main viewmodel. To solve it we have override ScopedRegionNavigationContentLoader plus to control either we want to inject scoped region manager or global one we have to us marking interfaces.
I created another question which is similar to current one: please check Prism 7 throws and exception when working with nested views. It will give you more details.
I have windows form application which has several user controls - each one is displayed when the relevant option is selected from a listbox.
Some of the user controls need to have access to data stored in a different user control so User Control A needs to know a value of a textbox stored in User Control B. I have done my exposing some properties in the user control B. This all works fine when the application first loads and no values are changed.
The problem I am having is if the value of the textbox in user control B is changed it is not picked up by user control A.
Do I have to do something with NotifyPropertyChanged? Any suggestions please?
Two solutions here:
Create a series of public properties and handle passing values where the Form objects are newed up.
Create an event to communicate when things change and register an event handler in the target Form to accept the change. This is similar in theme to the INotifyPropertyChanged interface but that's only required/advised for formal databinding scenarios.
I prefer events for this kind of thing.
I am writing a program that overlay's a toolbar onto another applications window. I am able to iterate through the MDI child windows and even access all the controls via PInvoke. The one thing I am trying to figure out is how to get the controls actual Name property.
I am able to see the name of the field using Hawkeye but I cannot figure out how it is getting the control name.
One thought is that it may be injecting something into the target application and running something like Control.FromHandle but I am not 100% sure.
Thanks for any help.
Unfortunately, the Name property of a control is a property of the .Net object that creates the window not of the control window itself. There is no way to get this value using the window handle - PInvoke or otherwise - from outside of the process.
You would need to do some variation on what Hawkeye appears to do. Attach to the process, examine the object hierarchy and/or inject code dynamically using the CLR Debugging API.
I have a Silverlight control with a method named DoSomething() decorated with the <ScriptableMember()> attribute. I then call this method successfully from JavaScript and proved by a little message box that apprears from the SL side that says "Method Called!".
Point is all that works. The problem I am having is that prior to calling this method I build up an ObservableCollection on the Silverlight control containing 1..n FileInfo objects. This works fine too and builds up as I add files to it. Each time I add a file, a messagebox tells me the count from Silverlight (i.e. "Count = 2").
Now the problem: when I call the method DoSomething() from JS and access that ObservableCollection the count = 0! To see what is going on I placed a message in the Silverlight control's constructor to see if it gets entered upon being called from JS, and indeed it does and appears to recreate the control.
If this is the case it kind of makes sense that my ObservableCollection has a count = 0 because it is not the same control instance where I built up the FileInfo collection.
So how in the world do I preserve the collection, and why would simply calling a method exposed to JS from Silverlight, recreate the control and not allow me to access it's given state? I don't want a new control, I need to manipulate it as-is. Or am I off base and doing something else wrong to cause this beahvior?
Thoughts? Thanks!
It turns out the instance registered was the culprit. The MSDN examples show registering a new instance of the type, but in my case I needed the actual instance of the Page Control itself which solved the problem.
So at the completion of my page's initialization, I could register the current page's instance like below:
HtmlPage.RegisterScriptableObject("SLControl", Me)
This allowed me from JS to access the control in it's current state which included all objects in the ObservableCollection as required. I blogged about this topic with code examples and the article below expands on this situation:
Get A Silverlight Control's Current Instance For Communicating Via The HTML Bridge:
http://allen-conway-dotnet.blogspot.com/2012/03/get-silverlight-controls-current.html
I have a WPF project based upon Prism Feb 2009 release set up as:
Shell exposes a single ContentControl as "MainRegion"
Another view (user control) defined in the Infrastructure project called SplitView exposes two additional regions "LeftRegion" and "RightRegion" also as ContentControl.
Some of my application's modules need to display their view in the MainRegion (one user control), while others need to display their views (two user controls in a split fashion) in the LeftRegion and RightRegion.
I have tried using scoped regions, assuming that specific Controllers would hold references to the scoped regions. So basically each controller interested in SplitView functionality should instantiate a new SplitView (user control) and activate it in the MainRegion while activating its two user controls in the LeftRegion and RightRegion of the newly created scoped SplitView regions.
I am using MVVM with View Injection to display the views.
Needless to say, something has gone horrifically wrong with this approach.
At runtime I get this exception, "An exception occurred while creating a region with name 'LeftRegion'. The exception was: System.InvalidOperationException: Specified element is already the logical child of another element. Disconnect it first."
Am I correct at assuming that the LeftRegion and RightRegion are trying to register themselves with the main RegionManager every time I instantiate the SplitView?
Sorry about the confusing/verbose post. Any suggestions? Best practices to achieve this?
Thanks in advance,
Ali
The exception of "Specified element is already the logical child..." is what happens when you try to add something to two places in the tree, so I imagine there might be some logical error in your code, or you are adding something twice.
I generally create my sub regions like this:
m_scopedRegionName = Guid.NewGuid().ToString(); /* EXAMPLE ! */
m_scopedRegionManager = m_regionManager.Regions[RegionNames.WORKSPACE_REGION].Add(myViewModel.View, m_scopedRegionName, true);
m_someThingRegion = m_scopedRegionManager.Regions[RegionNames.SOME_THING_REGION];
Then I add any new stuff into the "m_someThingRegion".