Difference between auto and * in WPF

Auto indicates that you can automatically adapt to the width of the displayed content. For example, you can automatically adapt to the width of the text.

* The width is allocated proportionally.

<ColumnDefinition Width="3*" /><ColumnDefinition Width="7*" />

Same, the rows can be defined in this way

<RowDefinition Height="3*" /><RowDefinition Height="7*" />

These numbers can be decimal.
If the number is default, the default value is 1.
In this example, column 2 is 1.5 times the width of column 1.

<ColumnDefinition Width="1.5*" /><ColumnDefinition />

Auto and * can be used together. In this example, the width of the last two rows is obtained proportionally after the first two rows are allocated.

<Grid.ColumnDefinitions>    <ColumnDefinition Width="Auto" />  <!-- Auto-fit to content, ‘Hi‘ -->    <ColumnDefinition Width="50.5" />  <!-- Fixed width: 50.5 device units) -->    <ColumnDefinition Width="69*" />   <!-- Take 69% of remainder -->    <ColumnDefinition Width="31*"/>    <!-- Take 31% of remainder --></Grid.ColumnDefinitions><TextBlock Text="Hi" Grid.Column="0" />

Difference between auto and * in WPF