I'm using the DevExpress library to load a bunch of shapes from a SQL server WKT datatable. As far as I am aware they get loaded directly from XAML, so the only thing that I can influence is the ConnectionString path in .CS.
<dxm:VectorLayer x:Name="WKT_Layer">
<dxm:SqlGeometryDataAdapter x:Name="WKT_Adapter"
SqlText = "SELECT [WKT], [SID],[FILL],[STROKE] FROM [TLORIS]"
SpatialDataMember = "WKT"
ConnectionString="{Binding WKTConnection}"/>
</dxm:VectorLayer>
Is there a way to force parts of XAML to load asynchronously, because the program can take up to 8 seconds to start while it loads all 10,000+ shapes? I'm also fine with using a loading spinner, for example WPF loading spinner, but I don't even know how to initialise it, as the UI is essentially frozen while the shapes are loading. I know how to solve this if I could approach it programmatically from .CS, but XAML is for me, for the most part, magic.
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I'm working on an old project that supports Windows Forms.
This project contains some ResourceManager for the support of a few localizations. The idea is that you call ResourceManager["SomeResource"] instead of Resource.SomeResource and it returns you a localized string.
And these localized strings are used in the code of the initialization of the form. For example, you have Form1, and in Form1.Design.cs there is some code like this:
Label label1 = new Label();
label1.Text = ResourceManager["SomeResource"];
So the label will be created with an already localized string in the Text.
And we need to add the functionality of changing the UI language without reloading the Form.
We can just set the every Text property of every controls again. But it's a lot of code, the form contains a lot of controls.
We can call the Form.InitializeComponents(), this method will recreate all controls with new localized strings, but in some cases, it works slowly because it reloads some big data again.
Is there some other way to refresh all UI controls and get the new localized strings? Do Windows Forms support some mechanism like Binding in the WPF to create the "connection" between the Text properties and localized resources?
I think that you can achieve this by use of Invalidate() either on the form itself or on a container control that your other controls may be encompassed by.
I'm working on an app, that displayes huge (10000+ elements) graphs in a wpf canvas.
I'd like a feature like in Visual Studio, when you can split the view of an editor (so I can view two distant part of the same graph at the same time).
I have some constraints:
data binding (creating the bindings) of graph elements makes the loading of big graphs very slow, so I'm not using MVVM, the "VM" knows about the view and updates it directly when needed
the children of the canvas are frameworkelements, since I use the Tag property
because of the number of graph elements, I don't want to keep two different view for each element for the two part of the split view
So it should be like displaying multiple parts of the same canvas in different places. You can't set two parents for the FrameworkElements in WPF, so the easiest way is out of question :(
What are my options? Should I reconsider my constraints or there is some workaround for this?
Let me know if you need any more details (it's a big application, so I can't give you every information).
Edit: duplicating with visual brush is not an option since I need proper input event notifications, so both view must be editable.
Options:
Bind the same data to two controls.
Use a visual brush and duplicate input on the real control.
Create a custom graphing control that can output two parts of the graph at once.
If binding to two controls is too slow, then I think you need to rethink your application. The very fact that you have so much data displayed at once that you need a dual view to see separate parts is disturbing. That should raise a red flag. The red flag would notify you that, "What I need, and what I have is different." And you should go back to the drawing board and find out what you really need.
Otherwise, it might be best to create a custom control. The graph is rendering in its entirety even though you only need small portions displayed. If you had your own custom control you could speed up the entire app by rendering only visible portions at a time, and splitting within the control.
I am trying to add images to a listbox with a "continuous scroll" so the user does not have to press any buttons etc to load the next set of images. The images are stored in Isolated Storage. I will be starting with 500 images. Loading 500 images to a listbox obviously does not work and just eats up all resources in a few seconds. Based on my research I need to use data virtualization so the images are retreived when they are required (on-screen) and disposed of when not-required (of-screen), as opposed to loading them all at once. I have searched the web for examples but have only been able to find code which retreives and displays text etc to populate the listbox as oposed to images stored in IS. I "belive" I need to use an Image within a Data Template, within a listbox and then bind to an IList using a custom class. I can bind the list box to a basic IList and that works ok (only 50 images) but when it comes to creating a custom class etc its over my head. Does anyone have an example of what I need that they would be happy to share? I havent been programming a year yet and have found most of my App requirements to be achievable with a litte research but I cant find any good pages or video that explains this exact requirement and its driving me crazy as I have spent days on it.
Failing that I will have to pay Telerik for their support and use their DataBoundListBox or pay a third party to write it for me, but I thought I would try here before parting with hundreds of dollars!
Thanks for your time(s) in advance!
Here is a proper implementation of data virtualization: http://blogs.msdn.com/b/ptorr/archive/2010/08/16/virtualizing-data-in-windows-phone-7-silverlight-applications.aspx
This is how you bind images to the image control: Image UriSource and Data Binding
To get data Data Virtualization on the Windows Phone 7 you can use the VirtualizingStackPanel class. In the MSDN you can find all the properties you may want to set. To use the control you put your list inside this control:
<VirtualizingStackPanel>
<YOUR LIST>
</VirtualizingStackPanel>
Since you would like to have a tutorial I can point you to Jevgeni Tšaikin blog post on ItemsControl virtualization. If you want more check out the post from Shawn Oster on Improving ListBox Performance.
I have a design question : In a pivot view (three "pages"), I have a lot of bindings. Well, about 12 items in each pivot view (TextBox, Map...).
I realized that these binding were slowing a lot the load of my view. But the binding on the first "page" of my pivot is the only one that needs to be loaded. I can put a progress indicator and load in a thread or something my other data (in fact, the binded data will be set only after an HTTPWebRequest).
How can I tell that to my application ? Like "onLoadPageX: bind items"
Thanks a lot, I don't know if i'm clear
You should be able to add a RoutedEventHandler for the Loaded event of each PivotItem. This event is fired when a particular PivotItem page is loaded; there is also a corresponding Unloaded event for when the page unloads, in case you need to free any resources.
Your question is quite vague but there are lots of options around showing a loading state, defering binding and having lots of controls in a pivot:
If you need to do anything that may take time then do it off the UI thread.
If you're doing something which takes time then you should show an indication to the user that something is happening. This could be a message or animation, depending on the likley time period and the rest of the application.
If your content is highly dependent upon data loaded from the web, be sure to have appropriate timeouts on failing to load the data. Also have useful messages if there is no data connection available.
If your UI is highly dependent on details loaded externally you could look at adding the controls to the UI once you know what you need to display.
If the UI will always have the same controls but different content in them, you could consider data-binding to objects which have placeholder content which is updated when the relevant information is downloaded from the web service.
If you have lots of items in your pivot you should consider defereing the loading of individual items so that you don't load them before they are needed. Only load the data on the items next to the one displayed. This way they appear preloaded to the user but ease the impact on the system.
I'm in the process of teaching myself WPF, and I have run into a small issue that I can't find the answer to.
My test app allows image files to be dropped into a StackPanel. Once an image is dropped, a new user control is added to the stack, and displays some meta-data about the file. All is working correctly, and I can iterate through the child controls to retrieve the values.
What I'd prefer to be able to do is allow the user to persist this data to a file, so they can suspend working on the data. The obvious way for me to do this is to store the data in a DataTable and serialise/deserialise it to xml. However, I don't know how to drive the collection of user controls from a DataTable or DataSet object - in fact, I don't even know if this is the right way to go about it in a WPF app. I am more than willing to admit my ignorance here and take better suggestions if there are any.
Summary of the app logic.
1) File is dropped (from Win explorer) onto a StackPanel
2) File triggers creation of a new user control, which is added to the StackPanel
3) Data is populated in the user control
4) Processing data involves iterating through the control collection.
What I'd like
1) File is dropped (from Win explorer) onto a StackPanel
2) File data is inserted into some persistable object (data table?)
3) updated data table drives the generation of the user control to be added to the displayed collection.
4) save / load functionality persists the data for re-use later.
Thanks in advance
You're on the right track with the second approach, what you need to look at is the ItemsControl - that's a thing which can have items added to it. It's the base for ListBox etc, and you can template it to work as you require. Then there's the DataTemplate which handles which controls are displayed and data binding to those controls when an item is added to the underlying data structure. There are quite a few examples around on the net, try Dr WPF.
In order to make everything work the underlying data structure must support change notification. As everything happens automagically, once the Xaml is setup, you can find yourself in an odd situation. You've added data to a data structure, which in turn has caused controls and data to appear in your ItemsControl. How do you link the data items and their visual controls. The answer is to use some built in static methods ItemFromContainer which links from the graphic to your underlying data item, useful to handle click events, and ContainerFromItem which does the reverse.