c# - using dt.AsEnumerable().Sum for columns having string/null value -

i using following way total of column datatable

string total = dt.asenumerable().sum(x => x.field<decimal>("col1")).tostring();

this works fine when values of col1 number.

my question is- lets consider if 1 value of col1 string or null or else other number, above code throw error obviously.

is there way check whether value number , use '0' instead if value not number.

i tried -

string total = dt.asenumerable().sum(x =>  x.field<decimal>("col1") int ? x.field<decimal>("col1") : 0).tostring();

but not sure if correct way.

please help

if it's not decimal string invalidcastexception in field<t> method. have know type is.

i assume col1 can null, field<t> supports nullable types:

decimal total = dt.asenumerable()  .sum(r => r.field<decimal?>("col1") ?? 0);

or without replacing null 0:

decimal? total = dt.asenumerable()  .sum(r => r.field<decimal?>("col1")); // use total.hasvalue , total.value

presuming string, use decimal.tryparse:

decimal d = 0; decimal total = dt.asenumerable()  .where(r => decimal.tryparse(r.field<string>("col1"), out d))  .sum(r => d);

if don't know type use object.tostring:

decimal total = dt.asenumerable()  .where(r => !r.isnull("col1") && decimal.tryparse(r["col1"].tostring(), out d))  .sum(r => d);

apart that, why store converted number again in string variable?

And