Invalid usage of aggregate function Sum() and Type: String

Question

I have a data table and a column contains int values. I have not specified the column with any datatype. When I perform the following.

object sum = dttest.Co         


        

Answer 1

You can use LINQ to Datatable:

 var result = dttest.AsEnumerable()
                    .Sum(x => Convert.ToInt32(x["Value"]));

Example how to Sum for specific name:

 var result = dttest.AsEnumerable()
                    .Where(r => r.Field("Name") == "FilterName")
                    .Sum(x => Convert.ToInt32(x["Value"]));