Below is my xaml code :
<Window x:Class="ScoresBank.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow">
<DockPanel LastChildFill="True">
<WrapPanel DockPanel.Dock="Top">
<ToolBar Height="25"></ToolBar>
</WrapPanel>
<WrapPanel DockPanel.Dock="Bottom">
<StatusBar Name="stbBottom" Height="25"
BorderThickness="2"
BorderBrush="Black">Example</StatusBar>
</WrapPanel>
<StackPanel DockPanel.Dock="Left">
<DockPanel LastChildFill="True">
<WrapPanel DockPanel.Dock="Top">
<Button Name="btnBrowseTags">TAGS</Button>
<Button Name="btnBrowseTitles">TITLES</Button>
</WrapPanel>
<ComboBox DockPanel.Dock="Top" Name="cbxCategory">
Example
</ComboBox>
<WrapPanel DockPanel.Dock="Bottom">
<TextBox Name="txtKeyword"></TextBox>
<Button Name="btnFind">Find</Button>
</WrapPanel>
<ListBox Name="lbxBrowse">
</ListBox>
</DockPanel>
</StackPanel>
<StackPanel DockPanel.Dock="Right">
<Button>Example</Button>
</StackPanel>
<Canvas>
</Canvas>
</DockPanel>
And this is my current layout view :
So, what I mean with filling the container are :
Making lbxBrowse to fill the mid-space of the DockPanel inside the left StackPanel.
Making txtKeyword to fill the WrapPanel.
Making stbBottom to fill the WrapPanel.
What I've tried :
It seems i've put them in a DockPanel with LastChildFill="True". But it seems doesn't work.
I don't know about this, since it's not possible to put it into a DockPanel first.
I don't know anything about this.
I don't use fixed size, since I need them to keep neat even when resized in multiple screen resolution. The fixed size on ToolBar and StatusBar seems required, otherwise, the text will be unseen.
P.S. If possible, I prefer the solution to be XAML code, rather than the C# code. Otherwise, C# code is fine too.
Thank you.
You should use a Grid. It is more easier to configure. Here is an example (I don't know exactly how you want to setup your layout).
<Window x:Class="SampleWpf.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="400" Width="600">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Button Margin="5" Content="TAGS"
Grid.Column="0" Grid.Row="0" />
<Button Margin="5" Content="TITLES"
Grid.Column="1" Grid.Row="0" />
<Button Margin="5" Content="EXAMPLES"
Grid.Column="2" Grid.Row="0"
HorizontalAlignment="Right"/>
<ComboBox Margin="5"
Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="1" />
<ListBox Margin="5"
Grid.Column="2" Grid.Row="1" Grid.RowSpan="2" />
<Button Margin="5" Content="EXAMPLE"
Grid.Column="2" Grid.Row="3" HorizontalAlignment="Left" />
</Grid>
</Window>
And the result:
With a grid you can set the height and the width of the columns and rows to a specific value (in points, pixels, cm, etc.), to column content (Auto) or proportional to the grid (with *).
Instead of using a StackPanel and DockPanel you can use Grid and set Grid.ColumnDefinitions and Grid.RowDefinitions. You can specify directly each row Height and each column Width. It's easier to use and it automaticly fit to content and container.
Related
I have created a UserControl that is suppose to display some text and then present a listbox for the user to select some item.
It is supposed to strech to the height to the grid cell it is placed in. And if there are more items than can fit on screen then to display a vertical scrollbar. After much trial and error I have finally managed to get it working as expected. But only when the row height is a pixel value. If I use any partial (by partial I mean the star symbol), the grid cell's height is not contained. Since I need the app the match screen size I need the partials to work.
Putting 100 items in the listbox suddenly makes the height of the entire grid is around 11000 (which I think is everything with no contraint). Meaning there is no scrollbar. See [Screenshot] https://i.stack.imgur.com/faES9.png.
I have a similar issue with my TextBox only horizontally. It will only activate when clicking on a specific pixel since it is empty the width is only 1 pixel. I hope someone can help me point out where I am going wrong, cause since I'm having more than one issue I suspect the problem is on my end.
This is my XAML code.
<UserControl x:Class="PackingStation.UserControls.SearchItemListing"
x:Name="SearchItemListingRoot"
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"
xmlns:local="clr-namespace:PackingStation.UserControls"
mc:Ignorable="d"
d:DesignHeight="1000" d:DesignWidth="1000">
<Grid DataContext="{Binding ElementName=SearchItemListingRoot}"
x:Name="TheGrid"
VerticalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="1*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height=".1*" />
<RowDefinition Height=".1*" />
<!-- If this value isnt a pixel value it will not vertically strech to available space -->
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<StackPanel HorizontalAlignment="Center"
Margin="0,0,0,0"
x:Name="TheHeadLineField"
Grid.Row="0"
Grid.Column="1">
<Label Style="{StaticResource LabelStyleHeadline32}"
Content="{Binding Title}"
HorizontalAlignment="Left"/>
<Label Style="{StaticResource LabelStyleText}"
HorizontalAlignment="Left"
Content="{Binding SubTitle}"
FontSize="20"/>
</StackPanel>
<!-- Search Field -->
<Border Style="{StaticResource Border6}"
x:Name="TheSearchField"
Grid.Row="1"
Grid.Column="1"
Background="{StaticResource ColorSummaryPanelBackground}"
BorderBrush="{StaticResource ColorSummaryPanelBorder}"
BorderThickness="1"
Margin="0,40,0,0">
<StackPanel Orientation="Horizontal"
Height="78"
HorizontalAlignment="Stretch">
<Image Stretch="Uniform"
Height="24"
Source="pack://application:,,,/WpfUI;component/Icons/Search.png"
Margin="36,0,0,0"
VerticalAlignment="Center"/>
<!-- Search Textbox -->
<!-- Similar issue with this textbox, only horizontally. With no content you have to hit a specific pixel to activate it -->
<TextBox Style="{StaticResource TextBoxSearchInlay}"
Name="TbxSearchTerm"
TextChanged="TextBoxBase_OnTextChanged"
HorizontalContentAlignment="Stretch"
HorizontalAlignment="Stretch"
Margin="20,0,0,0"/>
</StackPanel>
</Border>
<!-- Search results listings -->
<ListBox ItemsSource="{Binding Items}"
x:Name="TheListBox"
Grid.Row="2"
Grid.Column="1"
SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
ScrollViewer.VerticalScrollBarVisibility="Auto"
HorizontalContentAlignment="Stretch"
VerticalContentAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel HorizontalAlignment="Stretch" Margin="0,-10,0,-10">
<Label Style="{StaticResource LabelSearchItem}"
Content="{Binding Name}"
HorizontalContentAlignment="Stretch"
HorizontalAlignment="Stretch"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</UserControl>
I could repro your problem when I put your UserControl in a StackPanel. When it's in a Grid the ListBox shows its vertical scrollbar. So, try your UserControl in a Grid.
I think this answer will give a good explanation about Grid and StackPanel stretching behavior.
I am working on a Phone Dialer UWP application for Windows Mobile devices. In searching for dialer examples, I came across the PhoneCall sample that is bundled with Windows Universal Samples at https://github.com/Microsoft/Windows-universal-samples. The PhoneCall sample contains an example implementation of Dialer and a DialerPanel, complete with a text box to display or edit the number being typed, as well as the Call button. So far so good.
However, the sample dialer panel is hosted as a PivotItem in a tabbed interface implemented by MainPage.xaml, and it occupies the entire space available to it.
What I am looking for is something like a DialerPanel in the sample, but one that could shrink to fit in my Grid cell. I will have the available space split into two Grid cells, with the upper half occupying a custom control or an image, while the lower half will host the Dial Pad.
In my attempt to accomplish what I need, I modified the sample DialerPanel.xaml as follows:
I created a new outer Grid with two rows, each taking up 50% of the available space.
In the upper row, I added a rectangle with a fill of "Light Yellow"
In the lower row, I added the original Dialer Panel layout contained in a Grid (basically, I moved the ORIGINAL Grid into a Grid cell at Row 1, Column 0.
Below is the image of my XAML outline (with certain blocks collapsed for clarity):
Here's the XAML:
<UserControl
x:Class="PhoneCall.Controls.DialerPanel"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:PhoneCall.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="1*"/>
<RowDefinition Height="1*"/>
</Grid.RowDefinitions>
<Rectangle Fill="LightYellow" Grid.Row="0"/>
<Grid Grid.Row="1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<StackPanel Grid.Row="0">
<local:LinePicker Margin="0,20,0,0"/>
<Grid Style="{StaticResource DigitViewGridStyle}">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ScrollViewer x:Name="dialerNumberControlScrollviewer"
Grid.Column="0"
Style="{StaticResource DigitViewScrollerStyle}">
<TextBlock Style="{StaticResource DigitViewTextStyle}"
SizeChanged="OnDialerNumberControlSizeChanged"
Text="{Binding DialerPhoneNumber.NumberToDial, Mode=OneWay}">
</TextBlock>
</ScrollViewer>
<Button Grid.Column="1"
Command="{Binding ProcessBackspace}"
IsEnabled="{Binding DialerPhoneNumber.DialPadEnabled, Mode=OneWay}"
Holding="OnBackspaceHolding">
<FontIcon FontFamily="Segoe MDL2 Assets" Glyph="" FontSize="30"/>
</Button>
</Grid>
</StackPanel>
<StackPanel Grid.RowSpan="2" VerticalAlignment="Bottom">
<StackPanel Style="{StaticResource DialpadPanelStyle}">
<local:Dialpad x:Name="Dialpad"/>
<Button IsEnabled="{Binding DialerPhoneNumber.DialPadEnabled, Mode=OneWay}"
Style="{StaticResource AccentLongButtonStyle}"
Command="{Binding ProcessDialDialerNumberHeap}" >
<Button.ContentTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<FontIcon FontFamily="Segoe MDL2 Assets" Glyph="" RenderTransformOrigin="0.5,0.5">
<FontIcon.RenderTransform>
<CompositeTransform ScaleX=".75" ScaleY=".75"/>
</FontIcon.RenderTransform>
</FontIcon>
<TextBlock Text="Call"
Grid.Row="1"
Style="{StaticResource CaptionTextBlockStyle}"
Margin="0,4,0,0"
LineHeight="14"
HorizontalAlignment="Center" />
</Grid>
</DataTemplate>
</Button.ContentTemplate>
</Button>
</StackPanel>
</StackPanel>
</Grid>
</Grid>
</UserControl>
When I build the app with the changes above and run the sample, this is how it appears on the phone with my rectangle covering the Dial Pad:
I tried a couple of things including reduced fixed width and height for the Dialer Panel, but I could not make it work.
A couple of questions:
1. What am I doing wrong here and how can I fix it?
2. Is there a third party DialPad control (free or paid) that I can reference in my project and just use it?
Thanks for all your help!
I think the problem is in this line:
<StackPanel Grid.RowSpan="2" VerticalAlignment="Bottom">
This stack panel starts in row 0 where you the put
<StackPanel Grid.Row="0">
Can you try this?
<StackPanel Grid.Row="2" VerticalAlignment="Bottom">
This question already has an answer here:
How do I place a text over a image in a button in WinRT
(1 answer)
Closed 5 years ago.
I am learning different ways of achieving certain layouts with XAML in UWP (I know I'm late to the party but I just started with the UWP stuff!)
What I am trying to achieve is a main navigation page kind of thing from a hub control on my main page. At every HubSection, I will have button on each column of a 2-column grid, which will contain buttons. Ive'tried something similar to this post but the debugger kept failing to attach to my UWP app when I used images instead of textblocks.
Essentially, what I've got until now is something like this: (I've shared my code down below)
But what I am trying to achieve is each button having its own image background and a separate TextBlock with semi-transparent background at the bottom centre of the button... (I've only photo shopped it, this is the thing I am trying to achieve...)
So this is what I've tried so far... I've also tried the relative panel but no luck...
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="200" />
</Grid.ColumnDefinitions>
<StackPanel Orientation="Vertical" Grid.Column="0" Margin="10,10,10,0">
<Button HorizontalAlignment="Stretch">
<Grid>
<TextBlock HorizontalAlignment="Center">Column 0 Item 1</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</Grid>
<StackPanel>
<TextBlock>Column 0 Item 1</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</StackPanel>
</Grid>
My complete code looks something like this for this page.
<Page
x:Class="VaultManager.Terminal.Views.MainPage"
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"
mc:Ignorable="d">
<Grid Background="Black">
<Hub SectionHeaderClick="Hub_SectionHeaderClick">
<Hub.Header>
<Grid Margin="0,20,0,0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="80"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock x:Name="pageTitle" Text="My Hub Sample" Style="{StaticResource SubheaderTextBlockStyle}" Grid.Column="1" IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Top"/>
</Grid>
</Hub.Header>
<HubSection Header="Overview">
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="200" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="150" />
</Grid.RowDefinitions>
<StackPanel Orientation="Vertical" Grid.Column="0" Margin="10,10,10,0">
<Button HorizontalAlignment="Stretch">
<StackPanel>
<TextBlock>Column 0 Item 1</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</StackPanel>
</Button>
<Button HorizontalAlignment="Stretch" >
<RelativePanel>
<TextBlock>Column 0 Item 2</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</RelativePanel>
</Button>
</StackPanel>
<StackPanel Orientation="Vertical" Grid.Column="1" Margin="10,10,10,10">
<Button HorizontalAlignment="Stretch">
<StackPanel>
<TextBlock>Column 1 Item 1</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</StackPanel>
</Button>
<Button HorizontalAlignment="Stretch" >
<StackPanel>
<TextBlock>Column 1 Item 2</TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</StackPanel>
</Button>
</StackPanel>
</Grid>
</DataTemplate>
</HubSection>
<HubSection Header="Videos" Name="Videos">
<!-- yada yada -->
</HubSection>
<HubSection Header="Audios" Name="Audios">
<!-- blah blah -->
</HubSection>
</Hub>
</Grid>
Good job giving us all that info. You may want to take a look here since the asker in that question seems to have had a similar issue. The answerer suggested using a Grid instead of a StackPanel. Hope that helps. After that, you should be able to adjust the transparency of the text. If you are using visual studio you can just click on the text element and adjust the background brush from the Properties tab. The button w/ the image should look like this:
<Button HorizontalAlignment="Stretch">
<Grid>
<TextBlock Text = "Column 0 Item 1">
<TextBlock.Background>
<SolidColorBrush Color="(**Colour here**)" Opacity = "(**Opacity Here {1 being opaque and 0 being transparent}**)/>
</TextBlock.Background></TextBlock>
<Image Source="/Assets/Artwork/150x150/RobCos_Worst_Nightmare_trophy.jpg" Stretch="None" />
</Grid>
</Button>
I am trying to use WPF to present a report to the user. I went ahead and used the report wizard to create the chart that I wanted. My issue is that I cannot seem to get the actual chart to fill the Grid/WindowsFormsHost that it is nested in.
It seems to want to stay at whatever width and height that I stretched it to in the RDLC designer. Is there any way to set it to fill its parent when I initialize it?
Edit:
Heres my XAML:
<Window x:Class="CloudMonitor.Client.UI.Start"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Start" Height="972" Width="1315"
xmlns:convert="clr-namespace:CloudMonitor.Client.Convert"
xmlns:rv="clr-namespace:Microsoft.Reporting.WinForms;assembly=Microsoft.ReportViewer.WinForms" >
<Window.Resources>
<convert:ConnectionStatusConverter x:Key="ConnectionStatusConverter"/>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height=".9*"/>
<RowDefinition Height=".1*"/>
</Grid.RowDefinitions>
<Grid x:Name="ReportGrid" Grid.Row="0">
<WindowsFormsHost >
<rv:ReportViewer x:Name="_reportViewer"/>
</WindowsFormsHost>
</Grid>
<Grid Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Button x:Name="InitializeHubButton" Grid.Column="0" Content="Init Hub" Width="50" Height="20" HorizontalAlignment="Center" Click="InitializeHubButton_OnClick"></Button>
<Button x:Name="SendSimpleHailButton" Grid.Column="1" Content="Simple Hail" Width="90" Height="20" HorizontalAlignment="Center" Command="{Binding SendTestHail}" ></Button>
</Grid>
<Rectangle Fill="{Binding IsConnected, Converter={StaticResource ConnectionStatusConverter}}" Grid.Column="1" HorizontalAlignment="right" Height="20" Stroke="Black" VerticalAlignment="Bottom" Width="20"/>
</Grid>
</Window>
You need to create a Usercontrol and put the Report Viewer there then set it to your Grid.
Try replace this line from Window Definition:
Title="Start" Height="972" Width="1315"
With this:
Title="Start" d:DesignHeight="972" d:DesignWidth="1315"
This is a problem I've been trying to solve for a couple of days but I'm yet to find a good solution.
I have a main WPF window which contains a StackPanel. I also have a class called "MessageManagement" which contains a List of custom WPF controls called "MessagePreview".
MessagePreview
<UserControl x:Class="FinalYearProject.MessagePreview"
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="58" d:DesignWidth="254" Background="White" BorderThickness="1" BorderBrush="#FF320000">
<Grid Name="grid1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50" MaxWidth="50" MinWidth="50" />
<ColumnDefinition Width="197*" MinWidth="20" />
</Grid.ColumnDefinitions>
<Grid Grid.Column="1" Name="grid2">
<Grid.RowDefinitions>
<RowDefinition Height="31*" />
<RowDefinition Height="34*" />
<RowDefinition Height="33*" />
</Grid.RowDefinitions>
<Label Content="-ERROR-" Height="28" HorizontalAlignment="Left" Margin="2,1,0,0" Name="senderLabel" VerticalAlignment="Top" Foreground="#FF0000B4" Grid.RowSpan="2" />
<Label Content="-ERROR-" Height="33" HorizontalAlignment="Left" Name="previewLabel" VerticalAlignment="Top" Margin="-1,17,0,0" Grid.RowSpan="3" />
<Label Content="-Error-" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="0,16,6,0" Name="timeLabel" VerticalAlignment="Top" Grid.RowSpan="2" Width="196" />
</Grid>
<Grid Name="grid3">
<Grid.RowDefinitions>
<RowDefinition Height="29*" />
<RowDefinition Height="27*" />
</Grid.RowDefinitions>
<Image Height="38" HorizontalAlignment="Center" Margin="3,0,6,20" Name="image1" Stretch="Fill" VerticalAlignment="Bottom" Width="41" Source="/FinalYearProject;component/Images/twitter-bird-light-bgs.png" Grid.RowSpan="2" />
<CheckBox Height="16" Margin="15,0,22,6" Name="checkBox" VerticalAlignment="Bottom" Grid.Row="1" IsChecked="False" />
</Grid>
</Grid>
MessageManagement
List<MessagePreview> unread = new List<MessagePreview>();
public bool messagesLocked()
{
foreach (MessagePreview m in unread)
{
if ((bool)m.checkBox.IsChecked)
return true;
}
return false;
}
MainWindow C#
MessageManagement messageManagement;
MessagesPanel1 is a blank StackPanel inside MainWindow
if (!messageManagement.messagesLocked())
{
foreach (Message m in messageManagement.getListOfMessages()
{
MessagesPanel1.Children.Add(m)
}
}
When you add the custom control to the StackPanel it creates a duplicate of the original, which means changing a value on the controls in the StackPanel does not affect the controls in my MessageManagement List.
Is there a way that I can reference my original controls so that they change together? I looked into DataBinding but I'm not sure if that's the right area.
Again, You do not make a List of UI elements in WPF. You use an ItemsControl and set its ItemTemplate Property to whatever UI you need to represent your items:
<ItemsControl ItemsSource="{Binding Messages}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<!-- Everything you placed in your usercontrol, or else an instance of your usercontrol itself -->
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
If saying "change" you mead a data, inside WPF you never and ever need to access UI elements directly, as they are subject to change. What you have to do is to read the data bound to them. With correct databinding setupped on that controls you will have always updated information.
Accessing UI elements is never easy, but except that, it's completely unreliable way to access your data, as the way control is injected into the VisualTree may be changed, so your code will fail on next update.
For example on how to architect that can have a look here:
WPF Data Binding Examples