Sets or returns the width of the column as a number of '0' characters in the font of the 'Normal' style. This must be a value between 0 - 255.

 public double WidthInChars{ get; set; }
Public Property WidthInChars() As Double

While a cell can show more than 255 characters, a column may not exceed 255 characters in width.

          double colWidth = colProps.WidthInChars;
          colProps.WidthInChars = 20;

          Dim colWidth As Double = colProps.WidthInChars
          colProps.WidthInChars = 20