Need a custom formatter for excel cell value which may have different kinds of decimal value as string but we want numeric

Hi Team,

Need a custom formatter for excel cell value which may have different kinds of decimal value as string but we want numeric.

So that user can change the numeric values. At preset the below cells are text but we want as numeric.

We are generate the excel sheet using the C# program. For example We have a datatable with below values as string and we are generating the excel cell by cell..All we want is how to put the string values as numeric as it is in the datatable?