datatemplate in silverlight c#.net - c#

i am creating a datatemplate for items in listbox and loading it using
(DataTemplate)XamlReader.Load(template), where template is
string template = String.Concat(#
"<DataTemplate xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
<Border BorderBrush='#334873' BorderThickness='1,1,1,1' Width='450'>
<TextBox Height='72' HorizontalAlignment='Left' Margin='10,10,0,0' TextChanged="OnTextChanged" VerticalAlignment="Top" Width="460" />"
...................
"</Border></DataTemplate>");
i m getting error because of "OnTextChanged" event registerd.
I want to register a event in the template code.
How to do it?

To give you an answer: as you are using a Template it's rather difficult to map an event this way because the template doesn't know where it's put into. So OnTextChanged doesn't mean a thing in this context.
You should consider bindings instead. As you allready use a DataTemplate the usual story would be to Bindd the TextBox-Text property to some model-property
<TextBox Height='72' HorizontalAlignment='Left' Margin='10,10,0,0' Text="{Binding MyTextProperty}" VerticalAlignment="Top" Width="460" />"
Of course the DataContext here should have a property MyTextProperty but without your code (where you use the template) I can give no further details.

Related

WPF Issues with binding to styled button

I have created a RadioButton style which I use across my application. The display part of which uses the content presenter to display whatever content I added to the button:
<ContentPresenter>
<ContentPresenter.ContentTemplate>
<DataTemplate>
<Grid>
<TextBlock Text="{TemplateBinding Content}" />
</Grid>
</DataTemplate>
</ContentPresenter.ContentTemplate>
</ContentPresenter>
I'm then attempting to bind a decimal with a string formatter to the styled button like so:
<RadioButton Content="{Binding Stake, StringFormat={}{0:C}}" Style="{DynamicResource NeutralSelectorButtonStyle}" />
Stake is a decimal within a ViewModel which is set as the DataContext. When I run this up the content coming through is blank.
I made a change using a label in the DataTemplate rather than a TextBlock, this displayed the decimal but had not formatted it.
Can anyone explain why this is happening and possibly provide a solution.
If you require any more information just ask :)
Thanks in advance.
You are almost there just instead of setting the string format inside binding you should use ContentStringFormat property when in ContentControls.
Take a look at this Label (it works with any content control):
<Label Content="{Binding Path=MaxLevelofInvestment}" ContentStringFormat="Amount is {0}"/>
ContentPresenter also has this property:
http://msdn.microsoft.com/en-us/library/system.windows.controls.contentpresenter.contentstringformat%28v=vs.110%29.aspx
Try it out. I hope it works for you.

Accessing a list picker inside a PanoramaHeader Template

I have a panorama control in which I have create a header template to add a list picker inside it. (Just like the peoples hub to select social accounts)
<DataTemplate x:Key="PanoramaItemHeaderTemplate">
<ContentPresenter>
<StackPanel Height="129">
<TextBlock Text="{Binding}" FontSize="72" Margin="0,7,0,0" />
<toolkit:ListPicker x:Name="listPick" Margin="0,-21,0,0" BorderThickness="0">
<toolkit:ListPickerItem Content="twitter"></toolkit:ListPickerItem>
</toolkit:ListPicker>
</StackPanel>
</ContentPresenter>
</DataTemplate>
The panorama control is inside the MainPage.xaml file and I want to have access to the listpicker from the code behind to be able to populate it, and handle it selection events.
I don't know how to do this. I tried adding the x:name property to the list picker I don't have access to it in the MainPage code behind.
Any idea on how to approach this is very welcomed, thanks!
From what you have now, the quickest way to do what you want is to traverse the visual tree
See here for the implementation:
How to access a specific item in a Listbox with DataTemplate?
You cannot access the ListPicker by x:Name because it is not unambiguous: there is a ListPicker generated for each PanoramaItem in your Panorama. So the first question is, is it really the think you want to do? If so you need to populate it using a binding (ItemSource)
You can access an element inside another resource, consider this example:
<Grid Name="myGrid">
<StackPanel x:Name="stack1">
<TextBlock x:Name="abc"/>
</StackPanel>
</Grid>
We can only access the Grid myGrid in code by default. To get reference to the StackPanel we can do this:
StackPanel myStack=myGrid.FindName("stack1") as Stackpanel;
After that we can get reference to the TextBlock:
TextBlock myTextBlock=myStack.FindName("abc") as TextBlock;
You can modify myTextBlock after that as you may like. You can apply the same technique in your case and it will work.
Hope that helps :).

Passing data between pages wp7

I have a little question.
I have a data template like that :
<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Key="DangersItemTemplate">
<Grid Height="102" Width="447" Tap="Grid_Tap">
<Image Name="image" Source="{Binding Image}" HorizontalAlignment="Left" Width="90" />
<TextBlock Name="text" Text="{Binding Nom}" TextWrapping="Wrap" Margin="102,16,16,22"/>
</Grid>
</DataTemplate>
</phone:PhoneApplicationPage.Resources>
I want to use the Textlock control in the CSharp code to pass the Text property to the second xaml page, but I can't find the name of the control, it's inaccessible.
Any idea ?
Your binding the Text of the TextBlock so you must have the value in your datacontext. I'd add this value to the Querystirng and navigate to the page.
var text = ((Whatever) DataContext).Nom;
string page2Uri = string.Foramt("/PAge2.xaml?Nom={0}", text);
NavigationService.Navigate(new Uri(page2Uri, UriKind.Relative));
And then to get the data out of the querystring you can use the OnNavigatedTo method in your page, and then inspect this.NavigationContext.QueryString["nom"]
Or have a look into something like the MVVM pattern.
I just use VB.Net but I am sure you can convert.
Just use any shared variable in the application.
Here you can see it in an SourceCode example:
http://www.activevb.de/rubriken/kolumne/kol_30/res/nachtscanner.zip
Just use Public Shared MyText As String
in Application Class. This vairable you can access anywhere.
You can also use INotifyPropertyChanged for that shared property to bind.
Alternatively you can use Navigation Query. Read more here:
How can I pass query string variables with NavigationService.Navigate?

Editing child objects of a combo box using c# and Wpf

Backgorund
I am currently writing a program that allows a user to select a manufacture from a combo box. The combo box is created in wpf using the following wpf code segment:
<ComboBox Height="23" Margin="40.422,128.423,229.908,0" Name="itemProductManufacture" ToolTip="Click to open drop down menu" VerticalAlignment="Top" Text="Select A Manufacture" SelectionChanged="itemProductManufacture_SelectionChanged" DropDownOpened="itemProductManufacture_DropDownOpened">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding ManufactureId}" Width="0"/>
<Image Name="itemManufactureImage" Source="{Binding ManufactureImage}" Height="15" Width="70" Stretch="Uniform"/>
<TextBlock Text="{Binding ManufactureName}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
The data is provided form a database and each entry has a Image, a name and an Id (intentionally not shown)
Problem
I am trying to code the behaviour of the combo box so when it is open the image height is 50 and when it is closed it is 15 this is so the image is larger when it is first displayed and then smaller once selected so it doesn't take up too much space on the form.
I have tried editing the image propities using code but am unable to accsess it using its name or any other children of the combo box.
Thanks
Jonathan
As you are using data template you won't be able to access the directly by its name.
Try something like this -
Image image = this.itemProductManufacture.ItemTemplate.FindName("itemManufactureImage", this) as Image;
One thing I am not clear is whether you want to change image size for all the items or the selected one? If you need to access the image for a particulat item in combobox you may have to use the ItemContainerGenerator.ContainerFromItem, as explained in following posts -
WPF - ItemsControl - How do I get find my "CheckBox" item that is in the ItemTemplate?
http://www.sitechno.com/Blog/HowToUseAttachedPropertiesAsAnExtensionMechanismForACheckedListbox.aspx
look at this, To know the various ways of finding controls - How can I find WPF controls by name or type?
You can edit image properties from code using binding. Or you can use triggers in Datatemplate. When comboboxitems checked properties change, you can change height property of corresponding image
Try this:
<Image Height = "{Binding Path=IsDropDownOpen,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type ComboBox}},
Converter={StaticResource myBoolToHeightConverter}}" />
An example for Converter here

WPF Hyperlink Child

I have a WPF Hyperlink that I am able to click and get its NavigateUri property just fine. However, I want to be able to bundle some additional information with the Hyperlink so I can process it in my event handler. This is how it looks right now:
<TextBlock Grid.Row="0">
<Hyperlink ToolTip="{Binding Path=Contact.ToolTipPersonalEmail}"
Name="ContactHyperlink" Foreground="#FF333333"
RequestNavigate="HandleContactEmailClicked"
NavigateUri="{Binding Path=Contact.Email}"
>
<TextBlock Text="{Binding Path=Contact.Fullname}" Width="Auto"
HorizontalAlignment="Stretch"
TextTrimming="CharacterEllipsis"/>
<TextBlock Text="{Binding Path=Data1}" Name="data1" Visibility="Collapsed" />
<TextBlock Text="{Binding Path=Data2}" Name="data2" Visibility="Collapsed" />
</Hyperlink>
</TextBlock>
Basically, in my event handler, I want to be able to access the data inside the two textblocks that have visibility = "Collapsed" (data1 and data2). I liken this to "hidden" data in an HTML form.
I tried messing with the "Inlines" property of Hyperlink but that's not working, and since this is inside a DataTemplate I can't access data1 and data2 by name in my code.
Any ideas?
Thanks.
creating textblocks to hold that data is somewhat... overkill. I'd go with one of these two options:
use databinding, to place a specific
object into the hyperlink, then to
get it back, all you need to do, is
access the DataContext of the
hyperlink,and it will provide you
the class which holds data1 and
data2
attach the object which
populates data1 and data2 into the
Hyperlink's TAG attribute
In your event handler you can do something like this:
ContentPresenter presenter = (ContentPresenter)sender.TemplatedParent;
DataTemplate template = presenter.ContentTemplate;
TextBlock textBlock = (TextBlock)template.FindName("data1", presenter);
Probably not the prettiest way, but it works for me.

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