Unhandled Exception: System.InvalidCastException: Conversion from string "a" to type 'Double' is not valid. ---> System.FormatException: Unknown char: a
at System.Double.Parse (System.String s, NumberStyles style, IFormatProvider provider) [0x00000]
at System.Double.Parse (System.String s, IFormatProvider provider) [0x00000]
at Microsoft.VisualBasic.CompilerServices.DoubleType.Parse (System.String Value, System.Globalization.NumberFormatInfo NumberFormat) [0x00000]
at Microsoft.VisualBasic.CompilerServices.DoubleType.FromString (System.String Value, System.Globalization.NumberFormatInfo NumberFormat) [0x00000]
--- End of inner exception stack trace ---
at Microsoft.VisualBasic.CompilerServices.DoubleType.FromString (System.String Value, System.Globalization.NumberFormatInfo NumberFormat) [0x00000]
at Microsoft.VisualBasic.CompilerServices.DoubleType.FromString (System.String Value) [0x00000]
at Microsoft.VisualBasic.CompilerServices.Conversions.ToDouble (System.String Value) [0x00000]
at Test.Main () [0x00000]