Gets or sets a column's star-size, expressed in the format '{number}*'.

Star-sizing option performs a XAML-style dynamic sizing where column widths are proportional to the number before the star. For example, if a grid has three columns with widths "100", "", and "3", the first column will be 100 pixels wide, the second will take up 1/4th of the remaining space, and the last will take up the remaining 3/4ths of the remaining space.

Star-sizing allows you to define columns that automatically stretch to fill the width available. For example, set the width of the last column to "*" and it will automatically extend to fill the entire grid width so there's no empty space.