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I read and trying to get the article
Hierarchical Data Templates in Silverlight
By Jeremy Likness to work
I down loaded the project and it works, but when I put the appropriate files in my project it fails.
I have a question on the following snippet that in my project states is invalid XAML. The part that seems to be in question is
Image Source="{Binding IsUser,Converter={StaticResource TreeIcon}}"/>
Code Snippet from article:
<UserControl.Resources>
<Converters:UserGroupConverter x:Key="TreeIcon"/>
<Data:HierarchicalDataTemplate x:Key="UserGroupTemplate" ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal" Height="640" Width="640" Grid.Row="0">
<Image Source="{Binding IsUser,Converter={StaticResource TreeIcon}}"/>
<TextBlock Text="{Binding Name}"/>
</StackPanel>
</Data:HierarchicalDataTemplate>
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So have you included the TreeIcon converter in your project. This converter probably serves up the image for the tree node and that file will also need to be in place. Also your converter will need to be registered in your app.xaml to become a static resource.
Never underestimate the power of human stupidity
RAH
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Thankyou for the response. I have never used a HierarchicalDataTemplate...There is alot going on there. Between it and the usercontrol!
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The data template is very simple, to test it remove the image control and just work with the data. It is the image/converter that is confusing you.
Never underestimate the power of human stupidity
RAH
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Hi,
There is a WPf application written in VS express 2010. The database backend is sql server 2008 backend.
This application with the database is installed onto one machine in a small organization. The machine is on the network.
Everyday, a member of the staff uses this application for data entry, etc. All ok so far...
The staff member would also want to be able to work from home on this application. I have been told by the IT support person that there is no remote access available from outside of the company.
Question:
How is it possible for this or other users to be able to work on this system from home. The main thing is the user(s) to be able to access the database using this application. But with no remote access available I do not know what the solution is.
Any suggestions please?
Thanks
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If your IT person has denied remote access then the firewall is in place (and rightly so). You will need to open up the firewall so that an outside app can get at the database, this is a BAD idea. One way around it is to create a VPN that allows managed access from outside the firewall.
There are also design strategies that can be used like using a WCF rather than a direct connection to the database. The WCF can then service clients outside the firewall.
Never underestimate the power of human stupidity
RAH
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Hi,
If it is ok, can you please leborate what VPN is and how to set it up, etc?
Thanks
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arkiboys wrote: can you please leborate what VPN is and how to set it up
Not a chance - go talk to your IT guy, this is not an area I have any experience in and do not want to give you lousy advice. It is a major area of knowledge that I have almost no information on.
Never underestimate the power of human stupidity
RAH
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How can we set an expiry date of dll, if no function of that dll will be called in main application. This question is related to a DLL which is compiled from WPF theme .xaml file.
In C#, we will call that .XAML theme from DLL like -
ResourceDictionary skin = new ResourceDictionary();
skin.Source = new Uri(@"/Xceed.Wpf.Themes.LiveExplorer.v2.0;component\Xaml/ImplicitStyles.xaml", UriKind.Relative);
Application app = Application.Current;
app.Resources.MergedDictionaries.Clear();
app.Resources.MergedDictionaries.Add(skin);
And in XAML, we would call that .XAML theme from DLL like -
<ResourceDictionary Source = "/Xceed.Wpf.Themes.LiveExplorer.v2.0;component\Xaml/ImplicitStyles.xaml" />
Where 'Xceed.Wpf.Themes.LiveExplorer.v2.0' is DLL name, and, 'ImplicitStyles.xaml' is name of XAML theme file. In both ways, I can't see any function being called. But still, application throws an error after 45 days (of first run). Anyone interested can download the dll from Xceed web site, and check the same.
So, my question is - how can we create this kind of dll.
Please don't provide me links for Trial application/dll maker. Those can check only if some function gets called.
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Off the top of my head, you would just need a static class in the assembly. Static classes get automatically instantiated when the assembly is loaded.
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Can that static class stop this c# call-
skin.Source = new Uri(@"/Xceed.Wpf.Themes.LiveExplorer.v2.0;component\Xaml/ImplicitStyles.xaml", UriKind.Relative);
or this xaml call -
<ResourceDictionary Source = "/Xceed.Wpf.Themes.LiveExplorer.v2.0;component\Xaml/ImplicitStyles.xaml" />
Forget about expiry date. Can we set in DLL that if above codes are called from Main/User application - then it should throw an error?
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Yes. Static classes are instantiated whenever the DLL is loaded. It is possible to load a DLL as a resource only and never have any code executed, but I don't think thats whats going on here since xaml often references code behind.
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Your last line of answerSledgeHammer01 wrote: but I don't think thats whats going on here since xaml often references code behind
did the trick. As a newbie i couldn't think of that. I referenced a class in Xaml theme and it worked as I wanted...
Many thanks!! 
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I have a DataTemplate that is applied to a treeview item. It adds a textbox and button to the tree node. The problem is, when the user click the button or the textbox gets the focus, the tree node is not selected. How can I select the tree node when the button or textbox gets the focus? This is necessesary so that I can get to the data bound to the tree node.
Here's my XAML:
<DataTemplate DataType="{x:Type models:PartModel}">
<StackPanel Orientation="Vertical"
Margin="0,1,0,1">
<StackPanel Orientation="Horizontal">
<Image Source="/Abtech.Spares.UI;component/Media/Graphics/motherboard_enabled_96x96.png"
Height="16"
Width="16"
Margin="0,0,3,0"/>
<TextBlock Text="{Binding PartNumber}"></TextBlock>
<TextBlock Text="-"
Margin="3,0,3,0"/>
<TextBlock Text="{Binding PartDescription}"></TextBlock>
</StackPanel>
<StackPanel Orientation="Horizontal">
<Label x:Name="lblTribal"
Content="Tribal"/>
<TextBox x:Name="txtTribal"
Text="{Binding Tribal}"
Width="125"/>
<Button x:Name="cmdTribal"
Command="{Binding ElementName=ThisView, Path=DataContext.SelectTribalCommand}">
<Image Source="/Abtech.Spares.UI;component/Media/Graphics/Toolbar/search_16x16.png"
Margin="0,0,3,0"/>
</Button>
</StackPanel>
</StackPanel>
</DataTemplate>
Everything makes sense in someone's mind
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This is a well known issue in WPF. Its kind of expected in all item based controls that your data template doesn't have any focusable controls. When you do, you run into the problem that you are seeing, that focus was set to the child control completely bypassing the item.
Fortunately, the fix is easy. Add this to your resources section:
<Style TargetType="{x:Type TreeViewItem}">
<Style.Triggers>
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="IsSelected" Value="True" />
</Trigger>
</Style.Triggers>
</Style>
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Thank you! That did it!
Everything makes sense in someone's mind
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Turns out this works only to a point....
I have a hierarcy of objects like:
Product
| Category
| Part
Until the user first clicks a Part node in the tree, the controls in the Part template do not "know" about the underlying data source. Once a Part node is clicked, then I am able to determine the data object bound to it. In other words, the XAML you provided only seems to work after a part not is initially selected.
Also related to this, the WPF treeview's SelectedItem property is read-only, so it does not show up in the XAML intellisense.. I'm not sure why/how the WPF developers ever thought this would be a good design. So, since I cannot bind to the selected item, I really have no way of determining what node was selected without using the SelectedItemChanged event (I'm using MVVM).
Bottom line, I'm still stuck with:
1. Can't tell what node is selected
2. Can't tell from the button or textbox what the node's data object is.
[UPDATE]
I just changed the XAML you gave me to
<Style TargetType="{x:Type TreeViewItem}">
<Style.Triggers>
<Trigger Property="IsMouseCaptureWithin" Value="True">
<Setter Property="IsSelected" Value="True" />
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="IsSelected" Value="True" />
</Trigger>
</Style.Triggers>
</Style>
I added the "IsMouseCaptureWithin" and it seems to be working. Stay tuned.
Everything makes sense in someone's mind
modified 28-Nov-11 18:03pm.
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I'm not quite sure what you mean about having to select the part node, so you'll have to explain that further if this next part doesn't solve your issues:
There are a lot of properties that should be bindable, but are not. SelectedItem is one of them, SelectedItems on the ListView is another biggie and DialogResult is one of the biggest IMHO that should be bindable, but aren't.
You COULD use the SelectedItemChanged event in MVVM by using an Event to Command forwarder / converter, whatever the hell you want to call it. This generally looks something like:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<i:InvokeCommandAction Command="{Binding WindowLoadedCommand}" CommandParameter="{Binding ElementName=logonWindow}" />
</i:EventTrigger>
</i:Interaction.Triggers>
that assembly is part of the Blend SDK, but InvokeCommandAction doesn't let you forward the EventArgs as the command param, so you need a different forwarder I think you can copy EventToCommand out of MVVMLight... thats what I did in my MVVM framework.
BUT, all this is a bit messy and a PITA IMO because you need to add that XAML everywhere you want to trap events and you have to have the command mapper AND you need to define an ICommand to get the event and the handlers, etc.
So allow me to present alternative #2 ... this is what I did... for a lot of these properties (like the treeview SelectedItem and the listview SelectedItems), I added a second bindable version. VERY clean... looks just like the original property, but is now 2 way bindable. The TreeView.SelectedItem one is pretty simple:
public class TreeViewEx : TreeView
{
public static readonly DependencyProperty SelectedItemExProperty = DependencyProperty.Register("SelectedItemEx", typeof(object),
typeof(TreeViewEx), new FrameworkPropertyMetadata(null, new PropertyChangedCallback(OnSelectedItemExChanged)));
public TreeViewEx()
: base()
{
SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(TreeViewEx_SelectedItemChanged);
}
public object SelectedItemEx
{
get
{
return (object)GetValue(SelectedItemExProperty);
}
set
{
SetValue(SelectedItemExProperty, value);
}
}
private static void OnSelectedItemExChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TreeViewEx treeView = d as TreeViewEx;
if ((object)treeView != null)
treeView.SelectItem(e.NewValue);
}
private void TreeViewEx_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
SetValue(SelectedItemExProperty, e.NewValue);
}
}
Basically, all I do is add a SelectedItemEx DP. If the selection changes, it just updates the value of that DP to keep it in sync. If the DP changes, it updates the selected item in the treeview to go the other way.
then just switch your view to use TreeViewEx instead of TreeView and you can bind SelectedItemsEx to your VM.
-- modified 28-Nov-11 18:39pm.
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Ok, I think I get it.
I'm getting a comp error on this line:
treeView.SelectItem(e.NewValue);
SelectItem is not found in TreeViewEx. Looks like this should be defined in this class, but it's not there. What am I missing?
Everything makes sense in someone's mind
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Ah, yeah... I added that method to simplify node selection and to automatically expand and select hidden nodes -- something which is kinda tricky .
public bool SelectItem(object item)
{
if ((SelectedItem != null) && (SelectedItem.Equals(item)))
return true;
if (!ExpandAndSelectItem(this, item))
{
UpdateLayout();
return ExpandAndSelectItem(this, item);
}
return true;
}
and you'll need this one too (NOTE: I was too lazy to do it, but you need to change the TreeViewItemExs to standard TreeViewItems in this function):
private bool ExpandAndSelectItem(ItemsControl parentContainer, object itemToSelect)
{
TreeViewItemEx tvi = parentContainer.ItemContainerGenerator.ContainerFromItem(itemToSelect) as TreeViewItemEx;
if ((object)tvi != null)
{
tvi.IsSelected = true;
tvi.BringIntoView();
tvi.Focus();
return true;
}
for (int nIndex = 0; nIndex < parentContainer.Items.Count; nIndex++)
{
TreeViewItemEx currentContainer = parentContainer.ItemContainerGenerator.ContainerFromIndex(nIndex) as TreeViewItemEx;
if (((object)currentContainer != null) && (currentContainer.Items.Count > 0))
{
bool bIsExpanded = currentContainer.IsExpanded;
if (currentContainer.ItemContainerGenerator.Status != GeneratorStatus.ContainersGenerated)
{
EventHandler handler = null;
handler = new EventHandler(delegate
{
if (currentContainer.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
if (ExpandAndSelectItem(currentContainer, itemToSelect) == false)
currentContainer.IsExpanded = false;
currentContainer.ItemContainerGenerator.StatusChanged -= handler;
}
});
currentContainer.ItemContainerGenerator.StatusChanged += handler;
if (currentContainer.IsExpanded == false)
currentContainer.IsExpanded = true;
}
else
{
if (ExpandAndSelectItem(currentContainer, itemToSelect) == false)
currentContainer.IsExpanded = bIsExpanded;
else
return true;
}
}
}
return false;
}
I think that should be all you need . Now when you change the SelectedItemEx through binding and the node is hidden, it'll auto-expand all the necessary parent nodes and bring the requested node into view.
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OK, another problem that seems unsolvable - until some WPF Guru comes and hurls the painfully obvious answer to my face!
I have two DateTime fields in my model. They are mapped in the viewmodel as strings (look here http://joshsmithonwpf.wordpress.com/2008/11/14/using-a-viewmodel-to-provide-meaningful-validation-error-messages/[^] why).
Both DateTime fields and mapped fields are validated through IDataErrorInfo and everything works a breeze,until I want to validate the second field when the first field changes - say, I want the second date to be after the first date!I tried raising the PropertyChanged event in the setter of the first field but no luck!
Any ideas out there? Please???
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Just because it's not the field named in the property field as part of the validation, there's no reason you can't validate the other property as part of the validation based on the other property.
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Time for some code:
Property A:
public DateTime A
{
get
{
return _A;
}
set
{
_A=value;
RaisePropertyChanged("A");
}
}
Similarly:
Property B:
public DateTime B
{
get
{
return _B;
}
set
{
_B=value;
RaisePropertyChanged("B");
}
}
The A is validated by:
protected override String ValidateProperty(String propertyName)
{
switch (propertyName)
{
case "A":
break;
}
}
If I understand you correctly, you propose to call ValidateProperty(B) in the case "A"? 
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That is correct. If you have 2 properties dependant on each other, you need to validate both if one changes. To quote your example:-
public DateTime A
{
get
{
return _A;
}
set
{
_A = value;
RaisePropertyChanged("A");
RaisePropertyChanged("B");
}
}
public DateTime B
{
get
{
return _B;
}
set
{
_B = value;
RaisePropertyChanged("B");
RaisePropertyChanged("A");
}
}
Take a look at my article Validating User Input - WPF MVVM[^] that shows validating dependant properties.
When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman
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