I have a WrapPanel defined as follows in XAML...
<Page x:Class="SelectImages"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="320" d:DesignWidth="480"
Title="Select Images">
<Grid>
<WrapPanel Name="MyImagePanel" Width="Auto" Height="Auto" Margin="10,50,10,10" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" Orientation="Horizontal">
</WrapPanel>
</Grid>
</Page>
When I try to use the WrapPanel as below in my Code Behind I get a runtime error "Object reference not set to instance of object".
Private Sub AddImageToPanel(Image As FileSystemInfo)
MyImagePanel.Children.Add(NewPicture(Image))
End Sub
Can anyone tell me what I've done wrong?
I was navigating to this page using ...
Dim SelectImagesPage As New SelectImages(FolderPath, SelectedProductID)
Me.NavigationService.Navigate(SelectImagesPage)
Seems the constructor doesn't automatically initialise the components. Added InitializeComponent() to the constructor on my page and now it all works.
Related
I have a view template in a user control as below
<UserControl
x:Class="Configuration.Views.viewProfileTemplate"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid Background="Azure" Width="233">
<StackPanel Height="300" HorizontalAlignment="Left" Name="stackPanel1" VerticalAlignment="Top" Width="230">
<TextBox Text="{Binding Path=SomeProfileText}" Margin="10" />
<ListBox ItemsSource="{Binding Path=Profiles}" Height="70" Margin="10"/>
<CheckBox Content="CheckBox" Height="16" Name="checkBox1" Width="175" />
</StackPanel>
</Grid>
</UserControl>
The user control is defined as below in the main.xaml window
<Window x:Class="Configuration.TreeUI"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:views="clr-namespace:Configuration.Views"
xmlns:local="clr-namespace:Configuration"
Title="TreeUI" Height="300" Width="450" WindowStyle="ToolWindow">
I atempt to use the template with
<DataTemplate DataType="{x:Type local:ProfileViewModel}">
<Views:viewProfileTemplate/>
</DataTemplate>
But the compiler reports :
Error 1 The type 'Views:viewProfileTemplate' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built.
I again am missing som important point, but what ?
Going to owe someone a big drink .....
There are two potential causes for this:
1) If the data template is in a different assembly than viewProfileTemplate, you need to make the xaml reflect this:
xmlns:views="clr-namespace:Configuration.Views;assembly=ViewAssembly"
Note that this will also require a reference to be added to the project properly to function.
2) If this is a design time error, make sure to build the solution first. The WPF designer in VS often will report errors about missing types until you've built once, then it "works" properly.
I would like to add a specific instance of a class to the resources of a page then use that class as a converter, so in my page constructor I put:
this.Resources.Add("converterASD", new ASDConverter());
then bind to it like this:
<ListBox ItemsSource="{Binding Converter={StaticResource converterASD}}"/>
but I keep getting this exception:
Provide value on 'System.Windows.Markup.StaticResourceHolder' threw an
exception.
I'm a bit new to WPF, any advice would be appreciated.
We could use more information from the exception.
Two suggestions:
Make sure that you add the resource before the call to InitializeComponent().
Try switching it to a dynamic resource.
You can declare the Converter you would like to use in the resource section of the page like the following example. (I recommend you declare the converter in XAML instead of the code-behind)
Example:
<UserControl x:Class="Views.ConverterExample"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d" d:DesignHeight="300"
d:DesignWidth="300">
<UserControl.Resources>
<BooleanToVisibilityConverter x:Key="BoolToVisibilityConverter" />
</UserControl.Resources>
<Grid>
<CheckBox x:Name="VisibilityController" IsThreeState="False" />
<ListBox
Visibility="{Binding ElementName=VisibilityController, Path=IsChecked,Converter={StaticResource BoolToVisibilityConverter}}"
Height="100" Width="100" BorderBrush="Red" BorderThickness="1" />
</Grid>
</UserControl>
So the problem is this. I need UserControl which will have set Canvas.Top and Canvas.Left but these properties are binded from the ViewModel. For simplicity let's have this code for the user control with no code behind:
<UserControl x:Class="BadBinding.MyUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Canvas.Left="{Binding ElementName=slider, Path=Value}"
>
<Grid Width="100" Background="Red">
<Slider x:Name="slider" Minimum="100" Maximum="250" />
</Grid>
</UserControl>
And this code for the main window:
<Window x:Class="BadBinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525"
xmlns:local="clr-namespace:BadBinding"
>
<Canvas>
<local:MyUserControl />
</Canvas>
</Window>
I don't know why is binding not working. When you set Canvas.Left directly to some value everything is fine as well as writing content of the user control directly to the main window.
I think its because the UserControl is constructed befor being added to the Canvas and since Canvas.Left is an attached property it probably won't resolve correctly.
Try using a Reference binding.
<UserControl x:Class="BadBinding.MyUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Canvas.Left="{Binding Source={x:Reference Name=slider}, Path=Value}"
>
<Grid Width="100" Background="Red">
<Slider x:Name="slider" Minimum="100" Maximum="250" />
</Grid>
</UserControl>
Note: you may get a compile warning, but it will still compile.
But I think the best option would be to create a property on your usercontrol to bind the value, this will also work.
I tried a lot with Bindings but it dint worked for me too.. so if you wanna go with EventHandler then the following workaround may help you..
Remove the Bindings and add an event handler to ValueChanged event
In your MyUserControl.xaml
<UserControl x:Class="BadBinding.MyUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid Width="100" Background="Red">
<Slider x:Name="slider" Minimum="100" Maximum="250" ValueChanged="slider1_ValueChanged" />
</Grid>
</UserControl>
In your MyUserControl.xaml.cs
private void slider1_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
Canvas.SetLeft(this, slider1.Value);
}
I tried this and working for me if you find any problem then let me know..
I'm trying to build a small MVVM test application, but can't really figure how to display my user control in the MainWindow.
My Solution Explorer:
I got a resource dictionary:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:MVVM.ViewModel"
xmlns:vw="clr-namespace:MVVM.View">
<DataTemplate DataType="{x:Type vm:ViewModel}">
<vw:View />
</DataTemplate>
</ResourceDictionary>
I got my view:
<UserControl x:Class="MVVM.View.View"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<UserControl.Resources>
<DataTemplate x:Key="PersonTemplate">
<StackPanel>
<TextBlock Text="{Binding FirstName}" />
</StackPanel>
</DataTemplate>
</UserControl.Resources>
<ListBox ItemsSource="{Binding Path=Persons}"
ItemTemplate="{StaticResource PersonTemplate}" />
</UserControl>
and My MainWindow
<Window x:Class="MVVM.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:MVVM.ViewModel"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<ResourceDictionary Source="MainWindowResources.xaml" />
</Window.Resources>
<Grid>
</Grid>
</Window>
The most obvious and easiest way is to add the ContentControl element:
<Grid>
<ContentControl x:Name="mainContentControl" />
</Grid>
And after that set the Content property of this control to your view model, and the corresponding view will be loaded and applied automatically:
this.mainContentControl.Content = new ViewModel.ViewModel();
But I would prefer to use another way without datatemplates:
<Grid>
<vw:View x:Name="mainView"/>
</Grid>
this.mainView.DataContext = new ViewModel.ViewModel();
Build your VS2010 solution, then, go to your MainWindow's XAML.
On the left, there is a toolbar with button "Toolbox"
Open it, it contains all the possible WPF controls you could add to your UI
Your UserControl should appear on top of the list (in a category probably named "MVVM Controls"), just drag&drop it to your UI :)
I have a user control that I've created, however when I go to add it to the XAML in the window, Intellisense doesn't pick it up, and I can't figure out how to add it to the window.
You need to add a reference inside the window tag. Something like:
xmlns:controls="clr-namespace:YourCustomNamespace.Controls;assembly=YourAssemblyName"
(When you add xmlns:controls=" intellisense should kick in to make this bit easier)
Then you can add the control with:
<controls:CustomControlClassName ..... />
You probably need to add the namespace:
<Window x:Class="UserControlTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:UserControlTest"
Title="User Control Test" Height="300" Width="300">
<local:UserControl1 />
</Window>
Make sure there is an namespace definition (xmlns) for the namespace your control belong to.
xmlns:myControls="clr-namespace:YourCustomNamespace.Controls;assembly=YourAssemblyName"
<myControls:thecontrol/>
This is how I got it to work:
User Control WPF
<UserControl x:Class="App.ProcessView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
</Grid>
</UserControl>
User Control C#
namespace App {
/// <summary>
/// Interaction logic for ProcessView.xaml
/// </summary>
public partial class ProcessView : UserControl // My custom User Control
{
public ProcessView()
{
InitializeComponent();
}
} }
MainWindow WPF
<Window x:Name="RootWindow" x:Class="App.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:app="clr-namespace:App"
Title="Some Title" Height="350" Width="525" Closing="Window_Closing_1" Icon="bouncer.ico">
<Window.Resources>
<app:DateConverter x:Key="dateConverter"/>
</Window.Resources>
<Grid>
<ListView x:Name="listView" >
<ListView.ItemTemplate>
<DataTemplate>
<app:ProcessView />
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Window>