有没有办法从ObservableCollection过滤非零数据？

Question

is there a way to filter and group data from an ObservableCollection that has values greater than zero?

I have an excel file that load into an ObservableCollection but within the file could be some values with zero, and with this criteria, I need to run a query into SQL to get some data, but with these zero codes when I run the query doesn't return anything.

Example

I need to build a query for each of this combinations but there are more than 90k records in my ObservableCollection I'm looking for a clever solution to group all the records with the same pattern (In this case row 3 and 4 for example) does not need to have the same values only the same pattern in order to run one single large query with all of these codes.

Currently, I'm doing it in this way:

foreach (var item in _sourceStructure)
        {
            query = prepareQuery(item);
            RunQuery(query);
            if (errorMessage.Length > 1)
            {
                Console.WriteLine(errorMessage);
            }
            query = "";
        }

And in my preparQuery method, I have something like this

query = @"SELECT Column1, Column2, Column3, Column4 FROM SomeTable WHERE "

if (!string.IsNullOrEmpty(item.Column1.ToString()) && item.Column1.ToString() != "0")
                {
                    query = query + "Column1= " + "'" + item.Column1.ToString() + "'" + " and ";
                }
                if (!string.IsNullOrEmpty(item.Column2.ToString()) && item.Column2.ToString() != "0")
                {
                    query = query + "Column2= " + "'" + item.Column2.ToString() + "'" + " and ";
                }

This works "fine" but takes a lot of time to complete. If you find a better solution I can try it, I'm just looking for some advice.

Answer 1

Stop calling ToString so many times. You should do it once and store the value. And consider using string.Format or StringBuilder. Adding is very resource intensive.