为什么这个WPF按钮会拉伸到整个窗口？

Question

The button below always expands to be as wide as the TextBlock. I've tried StackPanel, DockPanel, Width="Auto", etc.

How can I make the button expand to the size of its own text (as in HTML) and not to the size of text in its environement?

    <DockPanel HorizontalAlignment="Left">
        <Button x:Name="ButtonFavorite"
                DockPanel.Dock="Top"  
                Content="Customers" 
                Margin="10" 
                Width="Auto"
                Click="ButtonFavorite_Click">
        </Button>

        <TextBlock DockPanel.Dock="Top" Text="this is a long text which makes the button stretch across the window, if this text is just a couple words, the button will be smaller, and this drives me up the wall"  Margin="10" TextWrapping="Wrap" />

    </DockPanel>

ANSWER:

Thanks Greg, that did it. Here is the full XAML that works now, you can right-click the button to change its Content so see that the button expands and contracts appropriately.

<Window x:Class="Test3784234.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <DockPanel HorizontalAlignment="Left">
        <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" >
            <Button x:Name="ButtonFavorite"
                    Padding="5"
                    Cursor="Hand" 
                    DockPanel.Dock="Top"  
                    Content="Customers" 
                    Margin="10" 
                    Click="ButtonFavorite_Click">
                <Button.ContextMenu>
                    <ContextMenu>
                        <MenuItem x:Name="menuItemReports" Header="Reports" Click="MenuItem_Click" />
                        <MenuItem x:Name="menuItemContracts" Header="Contracts" Click="MenuItem_Click"/>
                        <MenuItem x:Name="menuItemCustomers" Header="Customers" Click="MenuItem_Click" />
                        <MenuItem x:Name="menuItemDocumentation" Header="Documentation Creation Instructions" Click="MenuItem_Click" />
                        <MenuItem x:Name="menuItemEmail" Header="E-Mail" Click="MenuItem_Click" />
                    </ContextMenu>
                </Button.ContextMenu>
            </Button>

        </StackPanel>

        <TextBlock x:Name="TheMessage" DockPanel.Dock="Top" Text="Right-click the 'favorites' button to change its function." Margin="10" TextWrapping="Wrap"/>

    </DockPanel>
</Window>

Answer 1

All you need to do is set the HorizontalAlignment property on your button. It defaults to stretch therefore filling the available space.

<Button x:Name="ButtonFavorite"
        HorizontalAlignment="Left"
        Content="Customers" 
        Margin="10" 
        Width="Auto"
        Click="ButtonFavorite_Click">

Answer 2

Regarding your annoyance at the sizing of buttons, this is something that seems to be targeted at the designer in the designer/developer workflow, while you're clearly working on the developer portion. For the sake of development, I always apply a few styles in my App.xaml to ensure somewhat better button sizing. For example, in the application tag in your app.xaml file:

<Application.Resources>
  <Style TargetType="Button">
    <Setter Property="MinWidth" Value="60" />
    <Setter Property="MinHeight" Value="23" />
    <Setter Property="Margin" Value="3" />
  </Style>
</Application.Resources>

Regarding your actual question:

The problem is that your DockPanel is stretching to the width of the text and the button will naturally expand to fill the available area. If you want the quick and dirty solution you can do something like:

<DockPanel HorizontalAlignment="Left">
    <Button x:Name="ButtonFavorite"
            DockPanel.Dock="Top"  
            Content="Customers" 
            Margin="10" 
            Width="Auto"
            MaxWidth="100"
            Click="ButtonFavorite_Click">
    </Button>
</DockPanel>

Note the MaxWidth. If you want a more composable result, isolate your button in another panel. (I'm using a stackpanel because I believe someone else already used a grid in their example):

<DockPanel HorizontalAlignment="Left">
    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
        <Button x:Name="ButtonFavorite"
            Content="Customers" 
            Margin="10" 
            Width="Auto"
            Click="ButtonFavorite_Click" />
    </StackPanel>
    <TextBlock DockPanel.Dock="Top" Text="this is a long text which makes the button stretch across the window, if this text is just a couple words, the button will be smaller, and this drives me up the wall"  Margin="10" TextWrapping="Wrap" />
</DockPanel>

I like the StackPanel in this case because I find myself using it to create the horizontal "bar" of buttons along the bottom of a Form- err- Window in the right corner.

Answer 3

You could try isolating the button from the main panel by putting it in another panel.

<DockPanel HorizontalAlignment="Left">
    <Grid DockPanel.Dock="Top">
        <Button x:Name="ButtonFavorite"
                Content="Customers" 
                Margin="10" 
                Width="Auto"
                Click="ButtonFavorite_Click">
        </Button>
    </Grid>

    <TextBlock DockPanel.Dock="Top" Text="this is a long text which makes the button stretch across the window, if this text is just a couple words, the button will be smaller, and this drives me up the wall"  Margin="10" TextWrapping="Wrap" />

</DockPanel>

Answer 4

As another method to do this: You could change the button's template so it's essentially wrapped in a centered StackPanel. Something like this:

<Button Content="Back">
    <Button.Template>
        <ControlTemplate>
            <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
                <Button Content="{TemplateBinding Content}"></Button>
            </StackPanel>
        </ControlTemplate>
    </Button.Template>
</Button>

Or you could add a style to app.xaml (or any other place where you're storing your global styles) like this:

<Style TargetType="{x:Type Button}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate>
                <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
                    <Button Style="{x:Null}" Content="{Binding Path=Content, RelativeSource={RelativeSource AncestorType={x:Type Button}} }" FontWeight="Bold" Padding="5"></Button>
                </StackPanel>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Note that it's important to include the Style="{x:Null}" attribute on the button within the template if adding to the global styles, otherwise you'll get an infinite loop when it comes to rendering the button.

Answer 5

您可以将它们放在一个两列网格中，按钮只跨越一列，文本跨越两列吗？

Answer 6

Here's an example using a Grid layout versus a DockPanel. The idea is to have 2 columns and 2 rows. Put the Button it a single cell and make that row/column pair auto-sizing. Then put the TextBox into the second row and have it span both of the columns. This will essentially make the top-right cell just filler space and will achieve the behavior you're looking for.

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition />
    </Grid.RowDefinitions>

    <Button 
        x:Name="ButtonFavorite"
        Grid.Column="0"
        Grid.Row="0"
        Content="Customers" 
        Margin="10" 
        Width="Auto"
        Click="ButtonFavorite_Click">
    </Button>

    <TextBlock 
        Grid.Column="0"
        Grid.ColumnSpan="2"
        Grid.Row="1"
        Margin="10" 
        TextWrapping="Wrap"
        Text="this is a long text which makes the button stretch across the window, if this text is just a couple words, the button will be smaller, and this drives me up the wall" />
</Grid>