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That's a "feature" of virtual devices that they try to look as "physical" as possible... It may be impossible to differentiate between a virtual and real keyboard.
Some hints to the values you saw:
\\?\HID it is a "Human Interface Device"
VID_045E the Vendor Identifier is 045e (a hexadecimal value)
PID_079C the Product Identifier is 079c (the vendor sets the identifier of their products)
Strange that both keyborads have the same ids... (copy paste error?)
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No copy error. The properties for the physcal and virtual keyboards are identical except for the number of keys total property. The physical one has 154 keys while the virtual has 6 keys.
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Hello,
I need to play multiple instances of a same media file on a system and delete the file whenever last instance is deleted/closed.
There is no UI involved in it and media is played/stopped on some triggers.
I have been able to play the file using MediaElement and I am able to listen to same song in parallel and stop them individually.
The issue occured while deletion of the media file.
MediaElement doesn't release the filestream on MediaElement.Close() and the file is not deleted. It gets deleted only after application is closed.
I feel it to be a timing issue between MediaElement.Close() and File.Delete() as it happens intermittently.
I wanted to delete the file in order to create memory by deleting unused file(s).
It can be reporduced by creating atleast 2 MediaElement whose Source(Uri) refer to same media file.
After playing both the MediaElement, we close the media and delete the file(s). Sometimes it deletes the file, sometime doesn't.
Appreciate any thoughts on this issue of file being locked by the MediaElement and unable to delete instantly.
Thanks in advance!
Praveen Raghuvanshi
Software Developer
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Yes; it sounds like a "timing" issue (since it happens "sometimes"). Some things (like I/O) can happen asynchronously.
I would "queue" the name of the file and delete it on a separate thread; in a limited "retry" loop that sleeps a few milliseconds between tries. Run a timer / counter to see the best and worst case to satisfy your curiosity.
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Thanks!!!
Praveen Raghuvanshi
Software Developer
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Hello,
I am currently trying to implement a combobox to act similarly to the google search. It is working almost successfully, but I am having one last issue that I haven't been able to make any progress on all morning.
When the combobox gains focus, the first letter I type will get highlighted and if the user continues typing, it gets overwritten by the next letter typed. This is obviously frustrating and makes the functionality useless.
I have tried various settings to stop this from happening but so far nothing is successful. Has anyone experienced this problem in the past and can offer advice?
I found a post on SE with the same problem: https://stackoverflow.com/questions/17250650/wpf-combobox-auto-highlighting-on-first-letter-input[^] however the only proposed solution doesn't fix it and actually introduces more problems that I've noticed.
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hi,
i am trying to display Alternative images in listbox
<ListBox AlternationCount="2" x:Name="lstTiles1" Margin="0" >
<ListBox.ItemTemplate>
<DataTemplate>
<canvas>
<Image Source="Images\Tiles\Folder-n-design(right).png" Name="imgLoadRight" Margin="0,10,0,0" Visibility="Collapsed" />
<Image Source="Images\Tiles\Folder-n-design(center).png" Name="imgLoadCenter" Margin="0,100,0,0" Visibility="Collapsed" />
<Image Source="Images\Tiles\Folder-n-design.png" Name="imgLoadLeft" Margin="0,100,0,0" Visibility="Collapsed" />
<TextBlock VerticalAlignment="Top" Text="{Binding Name}" FontSize="16" FontWeight="Bold" Margin="90,20,0,0" Foreground="Black" />
</canvas>
<DataTemplate.Triggers>
<Trigger Property="ItemsControl.AlternationIndex" Value="0">
<Setter TargetName="imgLoadRight" Property="Visibility" Value="Visible" />
</Trigger>
<Trigger Property="ItemsControl.AlternationIndex" Value="1">
<Setter TargetName="imgLoadCenter" Property="Visibility" Value="Visible" />
</Trigger>
</DataTemplate.Triggers>
</DataTemplate>
<listbox.itemtemplate>
help me to display the Alternative Images...
nazeerpc
modified 28-May-14 8:03am.
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I am making a casino game. i want to make a Casino wheel which rotates ad stops at a point. Currently i am using a PNG file which is a image of a similar wheel and i am rotating it in context to an another image which contains a white ball only.
But this makes the project heavy due to images plus when the wheel is rotating, the view is blurred.
A concept that is in my mind is that i could make a jquery spining wheel and embeed it in silverlight user control. but it is last option .can any one help me in making a spinning wheel in 3d in silverlight with smooth transitions and should show the number in message box where it stops.
Thanks.
Vishal Kumar Singh
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I have control element and when i am doing drag and drop then that control have not image effects while doing operation. so please tell me a running examples for my requirement.
Hint is here demo of requirement image while drag and drop in wpf.
Thanks in advance.
Kalu Singh
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I want to know the best practice for reusing the resources in WPF. I am using lot of resources in my application. For example Resource A,B,C and D. Resource A is used in Control A, Resource B is used in Control B, Resource A,C,D is used in Control C.
I found below three ways but i want to know which one is the best practice.
1. Adding all the resource in a Resource Dictionary file and use the resource dictionary in all the Controls.
2. Create separate resource dictionary file for each resource and Merge only the required resource dictionary in controls.
3. Duplicating the required resource in each control.
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I see only 2 options and an idiotic suggestion.
I would go for something in between, group the resources by functionality and create a number of "libraries"
Never underestimate the power of human stupidity
RAH
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Thanks Mycroft Holmes  ,
Mycroft Holmes wrote: I would go for something in between, group the resources by functionality
Take if the Resource A and B are grouped by functionality to a Single Resource File. What if i used this resource in Control A which requires only Resource A. Is it ok to have Resource B also in the same file event thought it is not required for control A?. My concern is also about the memory and Performance.
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Sorry, I have not considered memory usage as an issue since the 90s but I would not hesitatein using 2 resource libraries for a single control.
Never underestimate the power of human stupidity
RAH
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Hi!
I have a WpfApplication with a TreeView and a Button.
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<Grid>
<TreeView Name="tvTree">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding List}" DataType="{x:Type local:BaseNode}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Header}" />
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<Button Width="20" Height="20" Content="Click" Click="Button_Click" />
</Grid>
</Window>
The TreeView's ItemsSource property will be populated from a list based on the BaseNode class. That class look like this:
public class BaseNode
{
System.Collections.ObjectModel.ObservableCollection<BaseNode> list = new System.Collections.ObjectModel.ObservableCollection<BaseNode>();
string header;
public BaseNode(string header)
{
this.header = header;
}
public string Header
{
get { return header; }
set { header = value; }
}
public System.Collections.ObjectModel.ObservableCollection<BaseNode> List
{
get { return list; }
set { list = value; }
}
}
The MainWindow.cs have this code:
public partial class MainWindow : Window
{
BaseNode a = new BaseNode("Base");
BaseNode b = new BaseNode("Sub1");
BaseNode c = new BaseNode("Sub2");
BaseNode ba = new BaseNode("Sub1Sub1");
BaseNode baa = new BaseNode("Sub1Sub1Sub1");
public MainWindow()
{
InitializeComponent();
a.List.Add(b);
a.List.Add(c);
b.List.Add(ba);
ba.List.Add(baa);
tvTree.ItemsSource = a.List;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
b.Header = "NewHeader";
}
}
Question 1:
When I click the button I would like to change the Header property of one of the BaseNodes. But the code for the Button.Click event won't do the trick. Just setting the BaseNode.Header property seem not to be enough. Instead I need to alter the Button.Click callback to:
private void Button_Click(object sender, RoutedEventArgs e)
{
b.Header = "NewHeader";
tvTree.ItemsSource = null;
tvTree.ItemsSource = a.List;
}
This does the job but seem to be very overkill for such a small thing.
Is there a better way to make the TreeView show the new value of the BaseNode.Header property?
Question 2:
Image I have populated the same TreeView with a bunch of BaseNode objects forming a tree with many branches of BaseNodes as well as branches in branches. I lack a way to, manually by code, open or close a branch in the TreeView.
I have found out that this is supported for the TreeViewItem control which have the IsExpanded property. My BaseNode class don't have such a property and including one I highly doubt it will "solve the problem".
With the TreeView.SelectedItemChanged event I can select any BaseNode in the TreeView and find out the actual BaseNode instance I selected. From this point I would like to be able to open or close the nested BaseNodes.
How to open or close a nested node in the TreeView which is not a TreeViewItem?
Best regards
/Mc_Topaz
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In regards to Question #1, your BaseNode needs to PROPERLY implement INotifyPropertyChanged on the Header and List properties.
In regards to Question #2, yes, the IsExpanded property is in the TreeViewItem. HierarchialDataTemplate doesn't support binding to that out of the box. However, you can easily derive a class HierachialDataTemplateEx which exposes an IsExpanded property and override the ValidateTemplatedParent method and bind it to TreeViewItem.
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Thanks SledgeHammer01!
I solved Question 1.
But I don't understand how to solve Question 2 by your explanation. I derived the HierarchicalDataTemplate class to this:
public class HierachialDataTemplateEx : HierarchicalDataTemplate
{
bool isExpanded = false;
public bool IsExpanded
{
get { return isExpanded; }
set { isExpanded = value; }
}
protected override void ValidateTemplatedParent(FrameworkElement templatedParent)
{
}
}
But I'm stuck after that. Can you continue my code and point me in the correct direction?
Also I got some further question for this solution:
1) Does this mean I need to stop using my BaseNode class and use TreeViewItem instead?
2) Using an derived version of HierarchicalDataTemplate class, does this mean my XAML code for the TreeView must be altered?
/Mc_Topaz
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The way you have it set up above, you'll only be able to control the IsExpanded "once" (at creation of the node). I.e. create a node expanded. If that is not sufficient and you need to be able to expand and collapse at will, you'll need to go a slightly different route. It is more complicated, so I won't go into that unless you need it .
Yes, you will need to slightly modify your XAML (assuming your namespace is local):
<local:HierarchialDataTemplateEx IsExpanded="True" ... >
</local:HierarchialDataTemplateEx>
In your ValidateTemplateParent() method, you just do something like:
base.ValidateTemplatedParent(templatedParent);
// set the properties on the TreeViewItem
if ((object)templatedParent != null)
{
TreeViewItem tvi = templatedParent.TemplatedParent as TreeViewItem;
if ((object)tvi != null)
tvi.IsExpanded = IsExpanded;
That should be sufficient for most use cases (creating a node in its expanded state). As I mentioned above, you need to do additional stuff if you need to control expansion state dynamically or get the node expansion state at runtime for saving expansion state, etc.
However, this basic way will let you for example create the top level expanded and the rest of the levels collapsed.
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Thanks again and for your effort!
I need to re-evaluate this. Maybe I don't need this full control of the TreeView.
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I am building a WPF application in which I need to do some OCR. I understand that it is possible to use the Microsoft Office Document Imaging 12.0 Type Library in Office 2007. However, I want my application to run also without office 2007 installed. Is there a separate download of Microsoft Office Document Imaging 12.0 Type Library that I can use for this purpose. I assume that all I need to do is to reference the appropriate dll in my application - correct?
NOTE: in local system my WPF Application working Fine.
Local system having Office 2007. but i want to run with out office..
any solution.... plz.
Nazeerpc
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A quick google search[^] reveals that:
From Wikipedia[^]:
Microsoft Office Document Imaging (MODI) is a discontinued Microsoft Office application that supports editing documents scanned by Microsoft Office Document Scanning. It is first introduced in Microsoft Office XP and is included in Office 2003...
The description clearly indicates what you should be doing now...
It is not available as a separate product anywhere, even not in later versions of office
See this: A C# Project in Optical Character Recognition (OCR) Using Chain Code[^]
And more results...[^]
Beauty cannot be defined by abscissas and ordinates; neither are circles and ellipses created by their geometrical formulas.
Carl von Clausewitz
Source
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Hi
Any help would be very appreciated.
i have a listbox defined in the MainPage.xaml which a bind to a collection of nested objects (boxes).
<ListBox x:Name="MyListBox"
ItemTemplate="{StaticResource NestedDataTemplate}"/>
The box:
public class Box
{
public string BoxName { get; set; }
public ObservableCollection<Box> Boxes { get; set; }
}
I fill each child collection of each box with a single box and I do that up to 15 times, so that the hierarchy contains up to 15 levels.
Box -Box --Box ---Box
...... 15 times
In the handler of the loaded event of the MainPage.xaml.cs the collection is populated like so:
ObservableCollection<Box> boxCollection = new ObservableCollection<Box>();
Box lastBox = new Box();
lastBox.BoxName = "Box Nr. 1";
lastBox.Boxes = new ObservableCollection<Box>();
for (int i = 1; i < 15; i++)
{
Box newBox = new Box();
newBox.BoxName = "Box Nr. " + (i + 1);
newBox.Boxes = new ObservableCollection<Box>();
newBox.Boxes.Add(lastBox);
lastBox = newBox;
}
boxCollection.Add(lastBox);
MyListBox.ItemsSource = boxCollection;
The listbox's items template is a hierarchical data template defined in the resource section of App.xaml.
<sdk:HierarchicalDataTemplate x:Key="NestedDataTemplate">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Border Grid.RowSpan="2" Background="LightGray" Opacity="0.5"/>
<TextBlock Text="{Binding BoxName}"/>
<ListBox Grid.Row="1" ItemsSource="{Binding Boxes}" ItemTemplate="{StaticResource NestedDataTemplate}"/>
</Grid>
</sdk:HierarchicalDataTemplate>
When I run the app, it crashes and throws the following exception which can be investigated in the Application_UnhandledException handler in the App.xaml.cs.
The exception:
Error HRESULT E_FAIL has been returned from a call to a COM component.
at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
at MS.Internal.XcpImports.FrameworkElement_MeasureOverride(FrameworkElement element, Size availableSize)
at System.Windows.FrameworkElement.MeasureOverride(Size availableSize)
at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth
Note: If I reduce the amount of hierarchy layers of the box collection, everything works fine.
Please help, I have been struggling for several days. I cannot find anything in forums or blogs.
Thank you
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It should be reasonably obvious you are running up against a limitation of the tool, possibly unpublished. Try using a treeview, it is the control designed to do this type of job.
Never underestimate the power of human stupidity
RAH
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I am implementing a Alerts Section Like This[^] in my application's Dashboard.
All or some of the text can be a hyperlink, with different commands bound to the links. The content of the messages will be automatically generated.
My first thought was have a table like this:
ImageName MessageDate Message ================================================================================================================
vehicle.jpg 2014-05/06 Vehicle Ford F150 Serial # ^L^256565^L^ has maintenance item ^L^Oil Change^L^ ready.
So it would look like:
"Vehicle Ford F150 Serial # 256565 has maintenance item Oil Change ready."
Clicking the serial # would open the vehicle screen. The Oil Change link would open the Maintenance screen.
I would then need to include in the message an action for each link. Like the link symbol, I could follow it with an enum item to denote what type of screen to open. And I would also need the PK's in there also.
Then, when the dashboard item is loaded, it would use a flow panel with both text and links in the data template so the Message column can wrap.
All this is fine, but it feels weird. Anyone done anything like this? Anyone got a better approach?
Thanks
If it's not broken, fix it until it is
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Kevin Marois wrote: an action for each link
Exactly, but it seems that you just happened to use the correct word. System.Action is the class to use, or (more typical in WPF) a Command object (take a look at the Command Pattern). When the link is clicked, you call the Invoke() method of the Action object.
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