I am trying to create a menu bar for my application. I have created a collection in xaml that I will contain menu items that my menu will bind to.
In xaml I have created an array that I use as my static resource for binding.
<coll:ArrayList x:Key="MenuOptionsList">
<model:DashboardMenuBarItem
Icon="the location of an image in my images folder"
DisplayName="The test that will appear under my button"
CommandName="someCommandInMyViewModel"/>
</coll:ArrayList>
I am using a listbox with a data template to show these items as follows.
<ListBox x:Name="lstNavigateTo" MinWidth="400" DockPanel.Dock="Top"
ItemsSource="{Binding Source={StaticResource MenuOptionsList}}"
ScrollViewer.HorizontalScrollBarVisibility="Disabled"
Style="{StaticResource horizontalListTemplate}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="5">
<Button Height="60" Width="60"
Command="{Binding Mode=OneWay, Path=CommandName}">
<Button.Content>
<Image Source="{Binding Path=Icon}" Grid.Row="0" />
</Button.Content>
</Button>
<TextBlock Text="{Binding Path=DisplayName}"
Width="100" TextAlignment="Center" Grid.Row="1" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
My problem is that I am using the MVVM design pattern and cannot get the command bindings to work on the button click. Previously I would have managed the button click like this.
Command="{Binding someCommandInMyViewModel}"
That would work fine but when I try to bind a command to a property of an item in my collection the command will not fire.
Does anyone know how I can achieve this.
The CommandName property in your collection is of type String, whereas the Command property on Button is of type ICommand. In what way are you expecting WPF to resolve an ICommand from a String? You'll need to help it: either create a converter and use it in your binding, or change your CommandName property so that it contains an actual ICommand rather than a String.
Related
Im new in wpf programming and i have an application with MVVM. I have a StackPanel and inside the StackPanel there is a ItemsControl named ListView and the Itemsource is my ObserveCollection NewProducts which conatins ProductID and Name.
So what is my code does, well it generates buttons with Names from my Collection NewProducts and i wanna give this buttons Command that triggers when i click on them.
I try this:
<StackPanel Grid.Row="1">
<ItemsControl x:Name="ListViewProducts" ItemsSource="{Binding NewProducts}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Border Margin="10" Width="auto" Height="auto">
<StackPanel>
<Border Width="100" Height="40" CornerRadius="5">
<Button Content="{Binding Name}" Tag="{Binding ProductId}" FontWeight="Bold" Command="{BindingSaleViewModel.SendCommand}"/>
</Border>
</StackPanel>
</Border>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</StackPanel>
But when i run my program and when i click on my buttons nothing happens. Its because the Command that i have in my SaleViewModel was not found in Product which is my Model class. And i wanna know if i can somehow get the path to my Command in my ViewModel.
Thanks, and please forgive me mine English, I know its bad.
Binding methods in WPF is unfortunately not that simple.
The command is actually a class, that implements the ICommand interface.
You can find an example here: How to Bind a Command in WPF.
Otherwise you can bind the click event to a method in code-behind <Button Click="Button_Click"/>
In code-behind:
private void Button_Click(object sender, RoutedEventArgs e)
{
// Add your code here...
}
Give your root element a name. eg:
<UserControl x:Class="blah"
other stuff
x:Name="root">
Then you can reference the root element in your binding, who's datacontext will (presumably?) be your SaleViewModel:
<Button Content="{Binding Name}" Tag="{Binding ProductId}" FontWeight="Bold"
Command="{Binding DataContext.SendCommand, ElementName=root}"
CommandParameter="{Binding}"/>
Also note the CommandParameter binding which will pass the button's data context (Product) through to your command, otherwise you won't know which product the command relates to.
<Grid.Resources>
<DataTemplate x:Key="trackTemplateY">
<TextBlock x:Name="txbValueY" Text="{Binding ValueX}" Margin="5" FontSize="11" FontWeight="Medium"/>
</DataTemplate>
</Grid.Resources>
<TextBlock Text="{Binding ElementName=txbValueY,Mode=OneWay,Path=Text}"
Background="Orange" Foreground="White"/>
I try this above code but i cant to bind the text, how can i bind inside resources textblock text to outside the resources, Thanks
I am guessing that you are trying to show Text present in TextBlock resource in your second non-resource TextBlock.
You don't need DataTemplate. As you will progress ahead in WPF journey, you will come to know about those.
Below code will show "Resource Text" in your second TextBlock.
<Grid.Resources>
<TextBlock x:Key="TbRes1" Text="Resource Text" x:Name="txbValueY" Margin="5" FontSize="11" FontWeight="Medium"/>
</Grid.Resources>
<TextBlock Text="{Binding Source={StaticResource TbRes1},Mode=OneWay,Path=Text}"
Background="Orange" Foreground="White"/>
All sorts of problems here:
You're specifying Mode.TwoWay in your TextBlock Text binding, it should be Mode.OneWay.
You're binding to the Label's Text property. Label doesn't have a Text property, only Content. And it's not a dependency property so you can't bind to it. (That said, a fluke of the internal mechanics does cause it to appear to work under certain conditions).
A template is exactly that: a template. You can't bind to something that doesn't exist, so the binding is meaningless.
Maybe you could clarify exactly what it is you're trying to do so we can suggest an alternative way of achieving it? Specifically, show us exactly how you're instantiating that DataTemplate.
UPDATE:
You need the first textbox to be created in order for the second one to bind to it, simply declaring it inside a DataTemplate doesn't cause that to happen by itself, so the direct binding will fail. Binding UI elements together like this should generally be avoided though, why can't you simply give the second textbox the same binding as the first?
<Grid>
<Grid.Resources>
<DataTemplate x:Key="trackTemplateY">
<TextBlock x:Name="txbValueY" Text="{Binding ValueX}" Margin="5" FontSize="11" FontWeight="Medium"/>
</DataTemplate>
</Grid.Resources>
<TextBlock Text="{Binding ValueX}" Background="Orange" Foreground="White"/>
</Grid>
If for some reason this isn't possible then you can also create a binding proxy object (see this page for details):
<Grid>
<Grid.Resources>
<local:BindingProxy x:Key="proxy" Data="{Binding ValueX}" />
<DataTemplate x:Key="trackTemplateY">
<TextBlock x:Name="txbValueY" Text="{Binding ValueX}" Margin="5" FontSize="11" FontWeight="Medium"/>
</DataTemplate>
</Grid.Resources>
<TextBlock Text="{Binding Source={StaticResource ResourceKey=proxy}, Path=Data}" Background="Orange" Foreground="White"/>
</Grid>
Again, there are ways to bind to the data template declaration if you really want to, but to do that I'd have to see details of how your data template is being created at runtime.
I have a GUI containing a listbox that holds rows of missing third party updates that resembles the following
INSTALLBUTTON | POSTPONEBUTTON | Application Name ApplicationVersion Upgrade Message
INSTALLBUTTON | POSTPONEBUTTON | Application Name ApplicationVersion Upgrade Message
Each row contains two buttons (Install and Postpone) as well as several properties read in from a list (application name, version, number of used deferrals, message that is displayed in red). The datacontext for the listbox is a list.
I'm having trouble figuring out how to bind the Install and Postpone buttons to the applications/rows. This is my current WPF:
<ListBox Name="ThirdPartyListBox" ItemsSource="{Binding}" Margin="0,70,0,0">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="C:\Users\test\Desktop\Project\ACME-WPF\ACME-WPF\window-new-3.ico" Margin="5" Width="50"/>
<Button Name="ThirdPartyInstallButton" Content="Install" Click="InstallThirdPartyUpdatesButton_Click" Margin="5,5,0,0" Height="25"></Button>
<Button Name="ThirdPartyPostoneButton" Content="Postpone" Margin="5,5,0,0" Height="25"></Button>
<TextBlock FontWeight="Bold" Text="{Binding Item2.Name}" Margin="12,25,0,0"/>
<TextBlock FontWeight="Bold" Text="{Binding Item2.RequiredVersion}" Margin="3,25,0,0"/>
<TextBlock Text="{Binding Item2.CustomUIMessage}" Margin="10,25,0,0" TextWrapping="Wrap" Foreground="Red"/>
<TextBlock Text="You have used " Margin="3,25,0,0"/>
<TextBlock Text="{Binding Item3.UsedDeferrals}" Margin="3,25,0,0"/>
<TextBlock Text=" of " Margin="3,25,0,0"/>
<TextBlock Text="{Binding Item2.MaxDefferals}" Margin="3,25,0,0"/>
<TextBlock Text=" deferrals for this update." Margin="3,25,0,0"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Once the Install button is clicked I need to execute a method that will trigger an install, using a number of the properties of the associated application list item.
In the click handler of the button, call the button .DataContext, that should have your object and its properties.
Instead of using "Click" use the command structures. To get the associated item's data in the command, use the CommandParameter.
CommandParameter="{Binding Path=.}" Command="{Binding ElementName=Root, Path=DataContext.InstallComponentCommand}"
This assumes that the Window/UserControl's is called "Root". Then, in your code-behind set up a "DelegateCommand" to do the work. This blog post contains a great tutorial on how to set it up: http://wpftutorial.net/DelegateCommand.html
The bound component object will show up as the object argument of the delegate.
Update
In the View Model:
public ICommand InstallComponentCommand {get; private set;}
//constructor
{
InstallComponentCommand = new DelegateCommand(p => InstallComponent(p));
}
private void InstallComponent(object data)
{
Component componentToInstall = (Component)data;
// Do whatever is necessary to install
}
As far as disabling the button goes, you could set a property like "InstallInProgress" and bind the "IsEnabled" property of the button to it.
Let me know if I can clarify anything!
I have a Page and a viewmodel is set as its datacontext. in that page I have a list. which is populating through a property in the viewmodel. List has a user control. and that user control has a button. I want that button to be bind with a command that is in viewmodel. Is there anyway to do that?
<Page DataContext=PageViewModel>
...
<ScrollViewer Grid.Row="3" Margin="20,0" Visibility="{Binding ByVenueSelected, Converter={StaticResource BooleanToVisibilityConverter}}">
<StackPanel>
<ItemsControl ItemsSource="{Binding EventsListByVenue}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<myControls:EventDetails /> <!--in this control i want to bind a command available in PageViewModel-->
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</ScrollViewer>
...
</Page>
with help of #FunksMaName, I solved this. I am sure there are more elegant and better approach, but yet this is a quick & easy solution for me:
<Button Style="{StaticResource NoHighlightButtonStyle}" Tag="{Binding link}" CommandParameter="{Binding Path=Tag,RelativeSource={RelativeSource Mode=Self}}" Visibility="{Binding link,Converter={StaticResource DataAvailabilityToVisibilityConverter}}" Command="{Binding Path=Event.LinkCommand,Source={StaticResource Locator}}" >
<TextBlock Margin="0,5" Foreground="SkyBlue" Text="{Binding link}" TextWrapping="Wrap" FontSize="16"/>
</Button>
things to note:
i think xaml searched the command parameter in context of command only, so it was giving me null parameter, while the same binding was working fine for textblock inside Button. So i tricked it to store the value in tag, and used it from there.
Tag="{Binding link}" CommandParameter="{Binding Path=Tag,RelativeSource={RelativeSource Mode=Self}}"
Hi I am trying to understand the best practise to use nested views.
I have an 'Attribute' View which is bound to collection of name value pairs in the view model. I need to reuse this at various places in my UI.
I have another 'Condition View' which has a string property and Dictionary(string,string) collection. I tried to create a text box and add the Attribute View control in the XAML
<StackPanel>
<StackPanel Orientation="Horizontal">
<Label Content="{x:Static l:StringResources.ConditionViewLabelText}" />
<TextBox Text="{Binding Type,Mode=TwoWay}" Width="100" />
</StackPanel>
<vw:AttributeView />
</StackPanel>
I want to bind the AttributeView's bound property to the Dictionary(string,string)'s collection property of the parent view model. Whats the best way to do it. I am not able to bind the vw:AttributeView to a ConditionViewModels ?
Can you please let me know the best practise to do this?
-- EDIT Please find my AttributeView (This is the child view's xaml code). The data template is bound to an observable collection on the AttributeViewModel
<StackPanel>
<ItemsControl ItemsSource="{Binding AllAttributes}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBox Width="100" Text="{Binding Name, Mode=TwoWay}" Margin="5,0,5,0" />
<TextBox Width="100" Text="{Binding Value, Mode=TwoWay}" Margin="5,0,5,0" />
<TextBlock Width="100" Text="{Binding KeyValue, Mode=OneWay}" />
<Button Width="50" Content="{x:Static l:StringResources.AttributeViewButtonDeleteText}" Command="{Binding Path=DataContext.DeleteAttribute, ElementName=AttributeControl}" CommandParameter="{Binding Name}"></Button>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<Button Name="btnSomething" Content="{x:Static l:StringResources.AttributeViewButtonAddText}" Command="{Binding AddNewAttribute}" />
</StackPanel>
</Grid>
Based on your comments that your parent / child relationship is not reflected in your view model, you have two options:
Create the relationship in your view model to reflect the relationship in your view, allowing you to navigate from the parent to the child and vice-versa should you need this.
Use a RelativeSource FindAncestor binding to navigate up the visual tree and locate a control bound to the parent view model, biding to this controls DataContext.
Option (2) will make you look clever, but option (1) is much simpler!