[RESOLVED] Using LINQ to Count Items in List<T>

[mojo69]

I would like to use LINQ to count how many times there is a match in a List<T>. The count need to tell me how may times that a productid and customerid exist in the List<T>. I have this code that I pieced together from googling this subject.

                    var drow = from DataRow myRow in dt.Rows
                                  where myRow["ProductID"].ToString() == PMTDProductID 
                                  select myRow;

Can I use this code to get the number of datarows? It is not currently and am not sure what is wrong. This will be the first time that I attempt to use LINQ.

[mojo69]

Changed my code to use the Find method for the List<T>;

                    YPUR yFind = _ypur.Find(delegate(YPUR yr)
                    {
                        return yr.ProductID == PMTDProductID;
                    }
                    );

I am getting a response that it found it (!null) or it did not (null). Can I use this to get the List<T> index?

[AceInfinity]

Something like this?

int T = dt.Rows.Count(r => r["ProductID"] == PMTDProductID);

[mojo69]

                    var results = from myRow in dt.AsEnumerable()
                                  where myRow.Field<string>("ProductID") == PMTDProductID && myRow.Field<string>("CustNo") == APMFCustNo
                                  select myRow;
                    int resultcnt = results.Count();

[AceInfinity]

                    var results = from myRow in dt.AsEnumerable()
                                  where myRow.Field<string>("ProductID") == PMTDProductID && myRow.Field<string>("CustNo") == APMFCustNo
                                  select myRow;
                    int resultcnt = results.Count();

Why did you post that? Are you still having issues or this is your solution? I don't get it... You can't just post code as a reply and assume people know what you mean.

As in my example though, you do not need the where clause, and you don't even need the select either. That's a waste of time using those, unless you're going to use the data afterwards. (If you used dot notation though, you would only need to end at where.)

[mojo69]

The code I posted is what is working for me right now. I will keep looking for better ways, including your example. The data will be used afterward. I started another thread to handle that. I appreciate you looking at this and apologize for not explaining the reason behind the last post.