I have a WPF application that I try to code using MVVM.The goal is to make something like a notification center, that lists different types of data.
To do this, I want to fill a ListView on the main page with different ViewModels. One ViewModel for each type of data.
The problem is:
When I put a (not a list) ViewModel in my ListView, it works fine. But if I put a list in my ListView, the program crashes on startup. I need the ListView to take a list (ObservableCollection perhaps) of mixed ViewModels.
I receive the error “Items collection must be empty before using ItemsSource.” at a seemingly random location in my code. Completely removing the code where the exception appears just causes it to show somewhere else.
I have the following:
C#:
public class MainViewModel : ObservableObject
{
private List<IPageViewModel> _items;
public MainViewModel()
{
_items = new List<IPageViewModel>
{
new StatusViewModel(),
new SettingsViewModel(),
new OverviewViewModel()
};
}
public List<IPageViewModel> Items => _items ?? (_items = newList<IPageViewModel>());
}
XAML:
<Window x:Class="InfoCenter.Views.Main.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:test="clr-namespace:InfoCenter.Views.Test"
xmlns:main="clr-namespace:InfoCenter.Views.Main"
xmlns:views="clr-namespace:InfoCenter.Views"
xmlns:settings="clr-namespace:InfoCenter.Views.Settings"
xmlns:status="clr-namespace:InfoCenter.Views.Status"
xmlns:overview="clr-namespace:InfoCenter.Views.Overview"
mc:Ignorable="d"
Title="MainView" Height="450" Width="500"
MaxWidth="1920"
WindowStyle="None" Loaded="MainViewLoaded"
SizeChanged="MainViewSizeChanged"
PreviewKeyDown="OnPreviewKeyDown"
GotFocus="OnGotFocus"
Closing="OnClosing"
ResizeMode="NoResize"
d:DataContext="{d:DesignInstance main:MainViewModel}">
<Window.Resources>
<DataTemplate DataType="{x:Type overview:OverviewViewModel}">
<overview:OverviewView />
</DataTemplate>
<DataTemplate DataType="{x:Type status:StatusViewModel}">
<status:StatusView />
</DataTemplate>
<DataTemplate DataType="{x:Type settings:SettingsViewModel}">
<settings:SettingsView />
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="24" />
<RowDefinition Height="*" />
<RowDefinition Height="30" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="24" />
</Grid.ColumnDefinitions>
<Button Command="{Binding ButtonClickCommand}" CommandParameter="Minimize" Grid.Row="0" Grid.Column="1">
<Image Source="/Resources/arrow-down-1.png"></Image>
</Button>
<ListView ItemsSource="{Binding Items}" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" ScrollViewer.HorizontalScrollBarVisibility="Hidden" PreviewMouseWheel="OnPreviewMouseWheel" ScrollViewer.VerticalScrollBarVisibility="Hidden">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="30" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" Content="{Binding Path=Items.Header}" />
<ContentControl Grid.Row="1" Grid.Column="0" Content="{Binding}" />
</Grid>
</ListView>
<StatusBar FlowDirection="RightToLeft" Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2">
<Image Width="24" Height="24" Source="{Binding ConnectionIcon}" />
</StatusBar>
</Grid>
</Window>
I really hope that you can help. I have been trying to fix it the whole day!
You have put one thing in the ListView contents here: A Grid control. Don't do that. There are two ways to populate a ListView in XAML: Bind ItemsSource or put items inside the content of the ListView element. You can't do both, and you did both, so it threw an exception.
Here's the ItemsSource version.
<ListView
ItemsSource="{Binding Items}"
Grid.Row="1"
Grid.Column="0"
Grid.ColumnSpan="2"
ScrollViewer.HorizontalScrollBarVisibility="Hidden"
PreviewMouseWheel="OnPreviewMouseWheel"
ScrollViewer.VerticalScrollBarVisibility="Hidden"
/>
I'm not certain what that Grid is for; you may have to find somewhere else to put it.
But my guess is that want it to be used to display the items. We can do that by making it into an ItemTemplate. I'm a little confused by it, though: What is Items.Header? Items is a List, which has no Header property. Does IPageViewModel have a Header property? For the moment I'll assume that's the case; let me know if I'm mistaken.
<ListView
ItemsSource="{Binding Items}"
Grid.Row="1"
Grid.Column="0"
Grid.ColumnSpan="2"
ScrollViewer.HorizontalScrollBarVisibility="Hidden"
PreviewMouseWheel="OnPreviewMouseWheel"
ScrollViewer.VerticalScrollBarVisibility="Hidden"
>
<ListView.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="30" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label
Grid.Row="0"
Grid.Column="0"
Content="{Binding Header}"
/>
<ContentControl
Grid.Row="1"
Grid.Column="0"
Content="{Binding}"
/>
</Grid>
<DataTemplate>
</ListView.ItemTemplate>
</ListView>
Based on the error I would recommend to change your XAML as was mentioned earlier in "Items collection must be empty before using ItemsSource."
Try this XAML:
<ListView ItemsSource="{Binding Items}" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" ScrollViewer.HorizontalScrollBarVisibility="Hidden" PreviewMouseWheel="OnPreviewMouseWheel" ScrollViewer.VerticalScrollBarVisibility="Hidden">
<ListView.View>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="30" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" Content="{Binding Path=Items.Header}" />
<ContentControl Grid.Row="1" Grid.Column="0" Content="{Binding}" />
</Grid>
</ListView.View>
</ListView>
Hope it will be helpful!
Related
I am currently in the process of making a 'Preferences' window in my C# WPF program.
The aim of this window is to have a ListView on the left, and a list of tweakable controls on the right.
Each item in the ListView directly corresponds to a Grid that contains all of the controls under the selected item's content.
Once the item in the ListView is changed, the current grid's visibility must be collapsed, and the grid that corresponds to the item selected's visibility must be changed to visible.
I thought that DataBinding might work for this, however I have no idea how to use it. Could someone please inform me how to implement this feature?
I have only one grid at the moment. The whole window looks like this:
<Window x:Class="DarkOrbit_Skill_Price_Calculator.DarkOrbit_Skill_Price_Calculator___Preferences"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:DarkOrbit_Skill_Price_Calculator"
mc:Ignorable="d"
Title="DarkOrbit Skill Price Calculator - Preferences" Height="360" Width="640" WindowStartupLocation="CenterScreen" WindowStyle="ToolWindow">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ListView Name="ListView_PreferenceOption" Width="150" Margin="5" SelectionChanged="SelectionChanged_ListView_PreferenceOption">
<ListViewItem IsSelected="True">
<StackPanel Orientation="Horizontal">
<Image Source="Images\Installing Updates.png" Height="35"/>
<TextBlock Text="Update" FontSize="14" FontFamily="Segoe UI" VerticalAlignment="Center" Margin="5"/>
</StackPanel>
</ListViewItem>
</ListView>
<Grid Margin="5" Name="Grid_Update" Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal">
<Label Content="Update Version Architecture" VerticalAlignment="Center"/>
<ComboBox IsReadOnly="True" Width="100" Margin="5">
<ComboBoxItem Content="64-Bit"/>
<ComboBoxItem Content="32-Bit" IsSelected="True"/>
</ComboBox>
</StackPanel>
</Grid>
</Grid>
</Window>
I have absolutely no clue as to how to swap the grid depending on the index selected.
You can bind the visibility of each grid to the selected state of its corresponding list item by referencing the ListViewItem element. Something like this:
<Grid>
<Grid.Resources>
<BooleanToVisibilityConverter x:Key="Converter" />
</Grid.Resources>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ListView Width="150" Margin="5">
<ListViewItem IsSelected="True" x:Name="One">
<TextBlock Text="Update" FontSize="14" FontFamily="Segoe UI"
VerticalAlignment="Center" Margin="5"/>
</ListViewItem>
<ListViewItem IsSelected="False" x:Name="Two">
<TextBlock Text="Foo" FontSize="14" FontFamily="Segoe UI"
VerticalAlignment="Center" Margin="5"/>
</ListViewItem>
</ListView>
<Grid Margin="5" Grid.Column="1"
Visibility="{Binding IsSelected, ElementName=One, Converter={StaticResource Converter}}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal">
<Label Content="Update Version Architecture" VerticalAlignment="Center"/>
<ComboBox IsReadOnly="True" Width="100" Margin="5">
<ComboBoxItem Content="64-Bit"/>
<ComboBoxItem Content="32-Bit" IsSelected="True"/>
</ComboBox>
</StackPanel>
</Grid>
<Grid Margin="5" Grid.Column="1"
Visibility="{Binding IsSelected, ElementName=Two, Converter={StaticResource Converter}}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal">
<Label Content="Update Something Else" VerticalAlignment="Center"/>
<ComboBox IsReadOnly="True" Width="100" Margin="5">
<ComboBoxItem Content="64-Bit"/>
<ComboBoxItem Content="32-Bit" IsSelected="True"/>
</ComboBox>
</StackPanel>
</Grid>
</Grid>
For those who are having the same predicament and want to use C# code to make this work, I eventually thought of the following code:
StackPanel[] allGrids = { Grid_1, Grid_2, Grid_3, Grid_4, ... }; //Replace StackPanel with the
//type of control you are using, e.g. Grid or WrapPanel.
foreach (StackPanel grid in allGrids)
{
grid.Visibility = Visibility.Collapsed; //collapse all grids
}
allGrids[(your listview/other control).SelectedIndex].Visibility = Visibility.Visible;
//make the grid you need visible
I made a popup control that can accept any view of type FrameworkElement. In addition, you can provide a view model, which will be bound to the DataContext of the child view being provided. Everything works, but it takes a couple of seconds to render the data. The view model has an ObservableCollection that contains about 300 items. So in all honesty, 300 items shouldn't cause any issues.
There is no lag what so ever, If I extract the xaml from the popup to a regular page.
So, is there something inside a Popup control that happens when it's Child content property is being set, that would cause such a delay? Because this is blowing my mind at the moment.
Thanks in advance!
[Update]
As requested, the XAML that forms the child content of the tool window:
<UserControl
x:Class="App.Controls.ContactSelector"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:interactivity="using:Microsoft.Xaml.Interactivity"
xmlns:core="using:Microsoft.Xaml.Interactions.Core"
mc:Ignorable="d" x:Name="contactSelector"
DataContext="{Binding ContactSelectorViewModel,Source={StaticResource Locator}}">
<Grid HorizontalAlignment="Stretch" Style="{StaticResource BaseGridStyle}">
<Grid.RowDefinitions>
<RowDefinition Height="1*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ListView Grid.Row="0" ItemsSource="{Binding ContactCollection}">
<ListView.ItemTemplate>
<DataTemplate>
<Grid Margin="12">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="1*" />
</Grid.ColumnDefinitions>
<!--<Image Margin="0,0,10,0" Grid.Row="0" Grid.Column="0"
Source="{Binding Thumbnail}" MaxHeight="35"
Visibility="{Binding Thumbnail, Converter={StaticResource ObjectNullToVisibilityConverter}}" />-->
<!--<Image Margin="0,5,5,5" Grid.Row="0" Grid.Column="0" MaxHeight="35"
Source="ms-appx:///Assets/Images/Contact.png"
Visibility="{Binding Thumbnail, Converter={StaticResource InverseObjectNullToVisibilityConverter}}" />-->
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding FullName}"
VerticalAlignment="Center"
Style="{StaticResource TextBlockMedium}" />
<!--<Grid Grid.Row="1" Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ItemsControl Grid.Row="0" ItemsSource="{Binding MobileNumbers}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid Margin="10,5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Margin="0"
Text="{Binding Number}"
HorizontalAlignment="Stretch"
Style="{StaticResource TextBlockMedium}">
<interactivity:Interaction.Behaviors>
<core:EventTriggerBehavior EventName="Tapped">
<core:InvokeCommandAction
Command="{Binding DataContext.SelectContact, ElementName=contactSelector}"
CommandParameter="{Binding}" />
</core:EventTriggerBehavior>
</interactivity:Interaction.Behaviors>
</TextBlock>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>-->
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
<!--<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Border>
<TextBlock Text="{Binding Key}"
VerticalAlignment="Center" HorizontalAlignment="Center"
Style="{StaticResource TextBlockMedium}"
Padding="5" Margin="5" FontWeight="SemiBold" />
</Border>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListView.GroupStyle>-->
</ListView>
</Grid>
</UserControl>
So I have commented out the entire section of the ItemsControl, but this did not solve the problem. When the Popup opens, it still takes quite a while to show the containing items.
It isn't slow when it's scrolling, it's slow in rendering the initial items.
The problem is in the ItemsControl which displays the MobileNumbers collection. You should not have an ItemsControl as an ItemTemplate for another ItemsControl (in your case, the ListView). You can do that only when you display small amount of items.
Because of this your MobileNumbers items are not virtualized and this is where the performance problem comes from, as all the items need to be displayed to render the item template.
You can try creating a flat list of objects, and then use ItemTemplateSelector to display different item templates for different types. For example you could have the following ObservableCollection as the ItemsSource:
Header
Contact info
Mobile number1
Mobile number2
Header
Contact info
Mobile number
etc.
I have a scenario where i have one control, which is using another control thru ListBox.ItemTemplate. I need to share Height and width between these 2 controls. How can we achieve that?
Main Conrol Xaml looks like as followings:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Grid.Row="0"
Text="{Binding Path=Caption,
Mode=OneWay}" />
<TextBlock Grid.Row="1"
Text="{Binding Path=Caption2,
Mode=OneWay}" />
</Grid>
<ListBox Grid.Row="0"
Grid.Column="1"
ItemsSource="{Binding Path=ViewModels}">
<ListBox.ItemTemplate>
<DataTemplate>
<Views:View2 />
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"></StackPanel>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
View2 xaml looks like as following:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0"
Grid.Column="0"
Text="{Binding Path=Value,
Mode=OneWay}"/>
<TextBlock Text="{Binding Path=Value2,
Mode=OneWay}"
Grid.Row="1"
Grid.Column="0"
/>
</Grid>
You can synchronize row height and column width using Grid.IsSharedSizeScope and the SharedSizeGroup attribute on ColumnDefinition and RowDefinition.
I'm not sure which elements you need to synchronize in your Xaml, but an example might be as follows:
Ia a parent element you use Grid.IsSharedSizeScope="True"
<Grid IsSharedSizeScope="true">
..
</Grid>
This synchronizes any columns (or rows) that have the same SharedSizeGroup within that scope (you can have multiple nested scopes).
So if your view.xaml looks like this
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition SharedSizeGroup="column1"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding Path=Value, Mode=OneWay}"/>
<TextBlock Text="{Binding Path=Value2, Mode=OneWay}" Grid.Row="1" Grid.Column="0"/>
</Grid>
Then all the textblocks will have the same width.
Hi I see there have been many questions about ListBox and filling the entire space for the DataTemplate but I still cannot get anything to work. What I have is a ListBox and the DataTemplate has a UserControl. How do I get my UserControl to stretch the data to fill the space?
MainWindow XAML snippet:
<ListBox x:Name="ConfiguredItemsList">
<ListBox.ItemTemplate>
<DataTemplate>
<local:ConfiguredItem DataContext="{Binding}" HorizontalContentAlignment="Stretch" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
UserControl XAML snippet:
<UserControl.Resources>
<local:ImagePathConverter x:Key="ImagePathConverter"/>
</UserControl.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="75" />
</Grid.ColumnDefinitions>
<Grid Grid.Column="0">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" x:Name="NameLabel" Text="Name:" />
<TextBlock Grid.Row="0" Grid.Column="1" x:Name="tbName" Text="{Binding Path=Name}" />
<TextBlock Grid.Row="1" Grid.Column="0" x:Name="DescriptionLabel" Text="Description: " />
<TextBlock Grid.Row="1" Grid.Column="1" x:Name="Description" Text="{Binding Path=Description}" />
<TextBlock Grid.Row="2" Grid.Column="0" x:Name="TimeLabel" Text="Time:" />
<TextBlock Grid.Row="2" Grid.Column="1" x:Name="Time" Text="{Binding Path=ChangeTime, StringFormat={}{0:h:mm tt}}" />
</Grid>
<Border Grid.Column="1" BorderThickness="1" BorderBrush="Black">
<Image Source="{Binding Path=WallpaperInfo, Converter={StaticResource ImagePathConverter}}" />
</Border>
</Grid>
Have you tried to set HorizontalContentAlignment to stretch on list box level?
<ListBox x:Name="ConfiguredItemsList" HorizontalContentAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<local:ConfiguredItem DataContext="{Binding}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Note: I have set HorizontalContentAlignment property of ListBox instead of Item.
In my WPF application (XAML posted below), I have a List View and below that I have some labels and text boxes. Everything below the ListView should anchor to the bottom of the window. Everything above the ListView needs to anchor to the top of the window. The ListView itself needs to expand vertically to fill in the space between. When I resize my window vertically, the only thing that should be changing size is the list view.
I keep everything in a stack panel at the root, but it doesn't size the listview like I want. Anyone know how I can accomplish this? I'm using C# .NET 4.0 and VS2010.
<Window x:Class="TaskManager.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" MinWidth="525" MinHeight="400">
<StackPanel Orientation="Vertical">
<Menu Name="mainMenu" Margin="0,0,0,5">
<MenuItem Header="File">
<MenuItem Header="Quit" />
</MenuItem>
</Menu>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,0,0,5">
<Label>View tasks for user:</Label>
<ComboBox Name="userList" MinWidth="150"></ComboBox>
</StackPanel>
<ListView Name="taskView" VerticalContentAlignment="Stretch">
<ListView.View>
<GridView>
<GridViewColumn Header="Task" Width="300"/>
<GridViewColumn Header="Hours" Width="50"/>
</GridView>
</ListView.View>
</ListView>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="353*" />
<ColumnDefinition Width="97*" />
<ColumnDefinition Width="53" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Label Grid.Row="0" Grid.Column="0">Task Description</Label>
<TextBox Grid.Row="1" Grid.Column="0"/>
<Label Grid.Row="0" Grid.Column="1">Hours</Label>
<TextBox Grid.Row="1" Grid.Column="1"/>
<Button Grid.Row="1" Grid.Column="2">Add</Button>
</Grid>
</StackPanel>
</Window>
It sounds like the DockPanel would help you to get the desired result. In the DockPanel, you can dock parts of your view to the top, bottom, left or right of the window. The last element added always covers the rest of the window. I modified your StackPanel code below.
<DockPanel>
<Menu DockPanel.Dock="Top" Name="mainMenu" Margin="0,0,0,5">
<MenuItem Header="File">
<MenuItem Header="Quit" />
</MenuItem>
</Menu>
<StackPanel DockPanel.Dock="Top" Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,0,0,5">
<Label>View tasks for user:</Label>
<ComboBox Name="userList" MinWidth="150"></ComboBox>
</StackPanel>
<Grid DockPanel.Dock="Bottom">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="353*" />
<ColumnDefinition Width="97*" />
<ColumnDefinition Width="53" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Label Grid.Row="0" Grid.Column="0">Task Description</Label>
<TextBox Grid.Row="1" Grid.Column="0"/>
<Label Grid.Row="0" Grid.Column="1">Hours</Label>
<TextBox Grid.Row="1" Grid.Column="1"/>
<Button Grid.Row="1" Grid.Column="2">Add</Button>
</Grid>
<ListView Name="taskView" VerticalContentAlignment="Stretch">
<ListView.View>
<GridView>
<GridViewColumn Header="Task" Width="300"/>
<GridViewColumn Header="Hours" Width="50"/>
</GridView>
</ListView.View>
</ListView>
</DockPanel>
This can be done using a Grid with 4 row definitions. All rows should have the height set to "Auto" except the one you want to expand, which should be set to "*"
<Window x:Class="TaskManager.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" MinWidth="525" MinHeight="400">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Menu Grid.Row="0" Name="mainMenu" Margin="0,0,0,5">
<MenuItem Header="File">
<MenuItem Header="Quit" />
</MenuItem>
</Menu>
<StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,0,0,5">
<Label>View tasks for user:</Label>
<ComboBox Name="userList" MinWidth="150"></ComboBox>
</StackPanel>
<ListView Grid.Row="2" Name="taskView" VerticalContentAlignment="Stretch">
<ListView.View>
<GridView>
<GridViewColumn Header="Task" Width="300"/>
<GridViewColumn Header="Hours" Width="50"/>
</GridView>
</ListView.View>
</ListView>
<Grid Grid.Row="3">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="353*" />
<ColumnDefinition Width="97*" />
<ColumnDefinition Width="53" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Label Grid.Row="0" Grid.Column="0">Task Description</Label>
<TextBox Grid.Row="1" Grid.Column="0"/>
<Label Grid.Row="0" Grid.Column="1">Hours</Label>
<TextBox Grid.Row="1" Grid.Column="1"/>
<Button Grid.Row="1" Grid.Column="2">Add</Button>
</Grid>
</Grid>
</Window>