MaxWidth of 'Auto'?

Question

I'm trying to create a grid that deals with screens of different sizes. My code currently looks like this:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>
    <TextBlock Grid.Column="0" ... />
    <TextBlock Grid.Column="1" ... />
</Grid>

This doesn't work correctly because I end up with a huge empty space at the end of the first column when I'm in fullscreen, and I want the text in each column to be adjacent. However, it DOES correctly shrink the first column when I shrink/resize the screen.

I also tried using code like this:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>
    <TextBlock Grid.Column="0" ... />
    <TextBlock Grid.Column="1" ... />
</Grid>

This code looks perfect when the app is fullscreen, but when I shrink/resize the screen the first column will NOT shrink to fit. It leaves my grid the same size, which pushes my text off of the smaller screen.

How can I cap the width at whatever size 'Auto' would be, and still have it resize like it is '*'?

Answer 1

How can I cap the width at whatever size 'Auto' would be, and still have it resize like it is '*'?

According to Define page layouts with XAML, Auto means the column will size to fit its content, * means after the Auto columns are calculated, the column gets part of the remaining width.

Width of ColumnDefinition cannot be set to Auto as well as *. But as your issue is when set Auto to both ColumnDefinition, it pushes your text off of the smaller screen, so here we may use AdaptiveTrigger. We can set Width to * by default this can ensure resize don't cut off the text. When the window resize to a larger size that will not lead the text cut off, the AdaptiveTrigger can help change the Width property from * to Auto. For example:

<Grid
   Background="Azure"
   BorderBrush="Pink"
   BorderThickness="2">
   <Grid.ColumnDefinitions>
       <ColumnDefinition x:Name="col1" Width="*" />
       <ColumnDefinition Width="Auto" />
   </Grid.ColumnDefinitions>
   <TextBlock        
       Grid.Column="0"        
       Foreground="Blue"
       Text="layouttest1layouttest1layouttest1layou"
       TextWrapping="Wrap"  />
   <TextBlock     
       Grid.Column="1"           
       Foreground="Red"
       Text="layouttest2layouttest2layouttest2layouttest2layout"
       TextWrapping="Wrap" />
   <VisualStateManager.VisualStateGroups>
       <VisualStateGroup>
           <VisualState>
               <VisualState.StateTriggers>
                   <AdaptiveTrigger MinWindowWidth="600" />
               </VisualState.StateTriggers>
               <VisualState.Setters>
                   <Setter Target="col1.Width" Value="Auto" />
               </VisualState.Setters>
           </VisualState>
       </VisualStateGroup>
   </VisualStateManager.VisualStateGroups>
</Grid>

The value of MinWindowWidth depend on the total Width of TextBlock. More details please reference the official sample.

Updated code as follows, if Width of TextBlock is dynamic.

XAML code

<Grid
    Background="Azure"
    BorderBrush="Pink"
    BorderThickness="2">
    <Grid.ColumnDefinitions>
        <ColumnDefinition x:Name="col1" Width="*" />
        <ColumnDefinition Width="Auto" />
    </Grid.ColumnDefinitions>
    <TextBlock        
        Grid.Column="0"  
        x:Name="txt1"
        Foreground="Blue"
        Text="layouttest1layouttest1layouttest1layou"
        TextWrapping="Wrap"  />
    <TextBlock     
        Grid.Column="1"           
        Foreground="Red"
        x:Name="txt2"
        Text="layouttest2layouttest2layouttest2layouttest2layout"
        TextWrapping="Wrap" />     
    <VisualStateManager.VisualStateGroups>
        <VisualStateGroup>
            <VisualState>
                <VisualState.StateTriggers>
                    <AdaptiveTrigger x:Name="adptivetrigger"   />
                </VisualState.StateTriggers>
                <VisualState.Setters>
                    <Setter Target="col1.Width" Value="Auto" />
                </VisualState.Setters>
            </VisualState>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
</Grid>

Code behind

 private void Page_Loaded(object sender, RoutedEventArgs e)
 {
     var testwidth = txt1.ActualWidth + txt2.ActualWidth;
     adptivetrigger.MinWindowWidth = testwidth;          
 }

Answer 2

Can you try this one

<Grid>
<Grid.ColumnDefinitions>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" ... HorizontalAlignment="Stretch"/>
<TextBlock Grid.Column="1" ... HorizontalAlignment="Stretch"/>

Here, I just added HorizontalAlignment="Stretch" property that will align textblock stretch within the column