writing excel cell values to generic list using c#

double.TryParse() will  return false if what's in the Excel cell cannot be parsed as a floating point number but, in this event,  the variable  'd' will be zero i.e. an exception will not be thrown.

Are you saying that a value of zero is not acceptable as the last parameter of the SKETCH constructor?  If so, is there some default value that could be used instead?

Hai its not taking any value and its showing false value i need to write data from excel cells to generic list using c#

I have made the attempt to do that but iam not able to read the values plz help me in this

Thanks for u help  i will try it

Given that particular error meesage, I'm fairly sure that this expression is the problem:

Convert.ToDouble(SketchWorkSheet.Cells[i,9])

The most likely explanation is that Cells[i,9] is either empty or contains nothing but spaces which would cause Convert.ToDouble to fail.

If that's the case and you'd be happy to pass zero in that situation, you could use:

double d;

double.TryParse(SketchWorkSheet.Cells[i,9], out d);

and then pass 'd' as the final parameter to the SKETCH constructor.