Question

I’ve a datatable which has a single text column ‘Title’ which can have multiple values with duplicates. I can remove the duplicates using a dataview.

DataView v = new DataView(tempTable);
tempTable = v.ToTable(true, "Title");

But how can i get the number of duplicates for each distinct value without any looping?

Answer 1

If you don’t want to loop or use Linq, so there is no way to do that but you can use a computed column on the data table with one more condition if applicable with you. That is the data should be in two related tables like this.

DataRelation rel = new DataRelation("CustToOrders", data.Tables["Customers"].Columns["customerid"],    data.Tables["Orders"].Columns["customerid"]);
data.Relations.Add(rel);

Given that customerid field as a Foreign key in the Orders table so it has duplicates.
You can get the count of the duplicates this way:

data.Tables["Customers"].Columns.Add("Duplicates",
   GetType(Decimal), "Count(child.customerid)");