Apparently, setting a UniformGrid's Background property affects the control's boundaries. See the following example:
<StackPanel>
<UniformGrid Rows="0" Columns="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Height="32" Background="Aqua" PreviewMouseUp="UIElement_OnPreviewMouseUp">
<!--Clicking on this UniformGrid fires the event-->
</UniformGrid>
<Border BorderBrush="Black" BorderThickness="1"></Border>
<UniformGrid Rows="0" Columns="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Height="32" PreviewMouseUp="UIElement_OnPreviewMouseUp">
<!--Clicking on this UniformGrid DOESN'T fire the event-->
</UniformGrid>
<Border BorderBrush="Black" BorderThickness="1"></Border>
</StackPanel>
Both UniformGrids take up space of the same size when rendered. However, clicking inside the second UniformGrid's area doesn't raise the PreviewMouseUp event. The only difference between the two controls is the Background property.
Why does the Background property affect the region where clicks (and presumably other input events) are registered?
Edit:
If I declare the Background to be Transparent, the event is raised properly. The interaction is ignored only when there's no Background declaration at all.
Related
Im having trouble controlling the exact layout of a button control with XAML.
It seems that whatever i do the button is of a minimum width.
I have a simple button with only a textblock inside the button. But the button has a lot of margin and padding that i cant seem to get rid of (i know of negative margins and padding).
The things i want to know is:
1. Why in the world was it designed this way.
2. what are the groundrules for controlling the exact layout of a button?
My code is as follows:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="80"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0"></StackPanel>
<Pivot Grid.Row="1">
<Pivot.Title>
<StackPanel Orientation="Horizontal" Margin="-15,-3,0,0" Background="red" Width="480">
<Button Background="Blue" x:Name="btnStudies" Click="btnMenuItem_Click" Width="20">
<TextBlock Text="Title" Foreground="White"></TextBlock>
</Button>
<Button Background="Green">
<TextBlock Text="Title" Foreground="White"></TextBlock>
</Button>
<Button Background="Blue" Click="btnMenuItem_Click">
<TextBlock Text="Title" Foreground="White"></TextBlock>
</Button>
<Button Background="Blue" Click="btnMenuItem_Click">
<TextBlock Text="Title" Foreground="White"></TextBlock>
</Button>
<Button Background="Blue" Click="btnMenuItem_Click">
<TextBlock Text="Title" Foreground="White"></TextBlock>
</Button>
</StackPanel>
</Pivot.Title>
</Pivot>
</Grid>
I want five buttons in a row but these are already too wide for the screen (windows phone). Changing the width doesnt seem to have any effect (why is it there).
The textBlock control within the button the button is as wide as the text on it, but i dont seem to have any control on the width of the button. In HTML you only have padding or margin when you define it but in xaml it just seems to be there and for me its unclear how to undo that.
*****EDIT*****
After reading Rachel's reply i decided to start from the ground up.
Using the code below i still have no control over how wide the button is because it uses a certain amount of padding that i cant seem to remove. The button has a width of about 110 when i define a width lower than that it doesnt change. Margins and paddings of 0 have no effect at all (dont want to use negative values just yet because that doesnt seem very intuitive). So the code below is very simple but still the button takes up an amount of space that i dont have any control over. I cant imagine a reason why it was designed this way.
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="400" />
</Grid.ColumnDefinitions>
<StackPanel Width="300" Background="Red" HorizontalAlignment="Left">
<Button Background="Blue" HorizontalAlignment="Left" Width="100" Margin="0" Padding="0">
<TextBlock Text="Title" Width="Auto" HorizontalAlignment="Left" />
</Button>
</StackPanel>
</Grid>
The type and size of the parent panel containing the control affects the size/layout of the child controls.
In your case, you have a Grid as your parent panel, and a Grid defaults to taking up all available space. In addition, children placed inside the grid default to taking up all available space as well unless you specify otherwise.
So your <Pivot> is being assigned a width equal to Grid.Width, and Pivot.Title sounds like it's being assigned a width equal to Pivot.Width, and StackPanel is being assigned a width equal to Pivot.Title.Width... you get the picture.
To specify that a control should not take up all available space, specify a HorizontalAlignment or VerticalAlignment property to tell it what side of the parent panel to dock the item on.
For example
<Pivot Grid.Row="1" HorizontalAlignment="Left">
or
<StackPanel OWidth="480" HorizontalAlignment="Left" ...>
If you're new to WPF's layout system, I would recommend reading through the codeproject article WPF Layouts: A Quick Visual Start to quickly learn what the main layout panels are for WPF.
I'm trying to get a window similar to a chat window, where a list of text items is drawn. The window should be resizable and each text item should wrap if it does not fit on one line.
What I have so far:
MessageItem - A user control, multiline TextBlock in a Border
<Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
<Border BorderBrush="Silver" BorderThickness="1" Height="Auto" HorizontalAlignment="Left" Margin="0,10,0,10" Name="messageContainer" VerticalAlignment="Top" Width="Auto">
<TextBlock Height="Auto" HorizontalAlignment="Stretch" Margin="0" Name="messageContent" VerticalAlignment="Stretch" Width="Auto" Text="This is some longer text. Wow that wasn't as long as I thought." TextWrapping="Wrap" Padding="10" />
</Border>
</Grid>
MessageBox - A user control with a ListView that holds MessageItems
<Grid Name="messageGrid" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
<ScrollViewer VerticalScrollBarVisibility="Auto">
<!--<StackPanel Height="Auto" HorizontalAlignment="Stretch" Margin="0" Name="messagePanel" VerticalAlignment="Stretch" Width="Auto">
</StackPanel> -->
<ListView HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch">
<local:MessageItem></local:MessageItem>
</ListView>
</ScrollViewer>
</Grid>
The Problem:
If I use the commented out StackPanel for holding MessageItems, It will shrink the MessageItem (and cause the text to wrap) correctly. If I use the ListView, it does not shrink.
I've more or less figured out why from research, but I haven't been able to figure out how to get around it. As far as I can tell I need to override MeasureOverride and/or ArrangeOverride, but I'm far too new to WPF to know WTF I'm doing. (rimshot)
I'm not sure why you're putting the ListView inside a ScrollViewer since the ListView has its own ScrollView internally.
In order to get your MessageItems to wrap you need to turn off any horizontal scrollbars, otherwise the container (ListView or ScrollViewer) will give the MessageItem as much space as it requires and show a scrollbar.
Try
<ScrollViewer ... ScrollViewer.HorizontalScrollBarVisibility="Disabled"/>
and
<ListView ... ScrollViewer.HorizontalScrollBarVisibility="Disabled"/>
although I'm not sure you even need the ScrollViewer.
You would probably be better off using a ListBox and an ItemTemplate instead of the ListView and user control
Here is what I tried to to:
Added a stackpanel to my window (Orientation: Horizontal)
Added a set of buttons to it
Set the first button's ZIndex to be higher than the second one
Increased the width of the first button
What I expected:
I expected the first button to be on top of the second button (atlest overlay)
StackPanel's width should not change unless the width of the first button is no more sufficient
What is happening actually:
First button's width increases and the second button moves towards the right accordingly. They stay on the same plane
StackPanel's width increases with increase in the first button's width
Here is my question:
I know that stackpanel has not considered ZIndex while arranging the items within itself, BUT WHY?? Shouldn't it consider the ZIndex of its children while arranging them???
The Stackpanel 'stacks' its children based on their widths, i.e. if you increase the width of an item (or increase its margin), the stackpanel will simply expand to accomodate this. If you want to force items within a stackpanel to overlap, you will have to change their location after the layout has been computed. You can perform this using a RenderTransform. See the example below:
<StackPanel Orientation="Horizontal" VerticalAlignment="Top">
<Button Content="One" Canvas.ZIndex="10">
<Button.RenderTransform>
<TranslateTransform X="10"/>
</Button.RenderTransform>
</Button>
<Button Content="One"/>
<Button Content="One"/>
<Button Content="One"/>
</StackPanel>
And yes, the ZIndex is respected. This is an attached proepry of Canvas, however, it seems to be used by the rendering engine directly rather than by Canvas, hence it works in the above code.
I tried to find some relevant info about how to set the z index of wpf layout elements and panels. Using a Canvas comes with a different set of positioning issues which I simply hadn't the time to investigate. Here is a simple solution using the Panel.ZIndex property in xaml.
<Grid>
<Border Width="100" Height="100" Margin="0,0,50,50" Panel.ZIndex="1" Background="Navy" Opacity="0.3"
VerticalAlignment="Top" HorizontalAlignment="Left">
</Border>
<Border Width="100" Height="100" Margin="50,50,0,0" Background="Fuchsia" Opacity="0.3">
</Border>
The resulting two square border elements will overlap. One can use stackpanels instead of borders and use this logic to overlap anything easily.
Here is the same code adapted to the button problem:
<Grid>
<StackPanel Panel.ZIndex="10" Margin="20,20,0,0" HorizontalAlignment="Left">
<Button Content="One" Width="50" Height="40">
</Button>
</StackPanel>
<StackPanel Orientation="Horizontal" Margin="50,0,0,0" >
<Button Content="Two" Width="50" Height="40"/>
<Button Content="Three" Width="50" Height="40"/>
<Button Content="Four" Width="50" Height="40"/>
</StackPanel>
</Grid>
A window has a Grid with two columns. The left column contains a control with a constant width but with a height that adapts. The right column contains a TextBox that takes up all remaining space in the Grid (and thereby in the Window).
The Grid is given a minimal width and height and is wrapped within a ScrollViewer. If the user resizes the window to be smaller than the minimal width/height of the Grid, scrollbars are displayed.
This is exactly how I want it to be. However, a problem occurs when the user starts typing text. If the text is to long to fit in one line in the TextBox, I want the text to wrap. Therefore I set TextWrapping="Wrap" on the TextBox. But since the TextBox has an automatic width and is wrapped in a ScrollViewer (its actually the whole Grid that is wrapped), the TextBox just keeps expanding to the right.
I do want the TextBox to expand if the window is expanded, but I don't want the TextBox to expand by the text. Rather the text should wrap inside the available TextBox. If the text don't fit within the TextBox height, a scrollbar should be displayed within the TextBox.
Is there a way to accomplish this?
Below is some code that shows my problem:
<Window x:Class="AdaptingTextBoxes.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="300" Width="400" Background="DarkCyan">
<Grid Margin="10" Name="LayoutRoot">
<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<Grid MinWidth="300" MinHeight="200">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Button Grid.Column="0" Margin="0,0,10,0" Content="Button" Width="100" />
<TextBox Grid.Column="1" AcceptsReturn="True" TextWrapping="Wrap" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" />
</Grid>
</ScrollViewer>
</Grid>
</Window>
You could use an invisible border (its hacky but it works - its how I tend to sort out dynamic textbox sizes in Xaml):
<Border BorderThickness="0" x:Name="border" Grid.Column="1" Margin="0.5" />
<TextBox Grid.Column="1" AcceptsReturn="True" TextWrapping="Wrap" Width="{Binding ActualWidth, ElementName=border}" Height="{Binding ActualHeight, ElementName=border}" />
Have you tried setting the MaxWidth property on just the TextBox?
Edit after OP's comment
I would try getting rid of the ScrollViewer. The sizing used in the Grid's layout should take care of re-sizing and the scroll bar settings on the TextBox should take care of the rest.
The answer is based on Leom's answer.
The solution works great when you enlarge the window, but the resizing is not smooth when you make the window smaller. As the textbox participates in the grid's layout, it has to perform layout process multiple times. You can fix that by putting the texbox in the canvas, so the change of the size of the textbox no longer triggers the grid's re-layout.
The updated code:
<Border BorderThickness="0" x:Name="border" Grid.Column="1" Margin="0.5" />
<Canvas Grid.Column="1">
<TextBox AcceptsReturn="True" TextWrapping="Wrap" Width="{Binding ActualWidth, ElementName=border}" Height="{Binding ActualHeight, ElementName=border}" />
</Canvas>
I have a ListBox displaying some items, and in certain modes I "stamp" a kind of watermark across the top of it. I've done this with a Border containing a TextBlock with an Opacity of 0.5. All this works nicely.
However, I still want the user to be able to click on the items in the ListBox but if I click on the "stamp" it obviously eats the click events and they're not seen by the ListBox.
What do I have to do to prevent this? (i.e. allow the ListBox to see the Click event)
Thanks,
Craig
You can do this with the IsHitTestVisible property:
<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ListBox>
<ListBoxItem>a</ListBoxItem>
<ListBoxItem>b</ListBoxItem>
<ListBoxItem>c</ListBoxItem>
</ListBox>
<Border Opacity="0.2" Background="Cyan" BorderBrush="Black" BorderThickness="5" IsHitTestVisible="False" >
<TextBlock Text="EXAMPLE" FontSize="20" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</Grid>