How to use multi condition in where of list c#

Question

Please check my code. I want to filter the list by date, but this code doesn't working.

List<QueryRow> queryResult = App.StorageRepository.Query("appointments_appointment");
queryResult.Where(item => 
    {
        var startDate = Convert.ToDateTime(item.Document.GetProperty("startDate"));
        if (startDate == date)
            return true;
        else
            return false;
    });

Please see [How to Ask](http://stackoverflow.com/help/how-to-ask). You need to tell us what you're trying to do and what is actually happening. — stelioslogothetis, May 10 '17 at 18:40
Are you hoping that the compiler will guess that `date` is supposed to refer to some property of `item`? Compilers don't pick up on coy hints like that. This is why Passive-Aggressive Programming isn't really a thing. — 15ee8f99-57ff-4f92-890c-b56153, May 10 '17 at 18:41
You should be using `.Any()` if you want to return a boolean, `Where()` will return QueryRow objects. — prospector, May 10 '17 at 18:46
Additionally you may want to compare only the [`Date`](https://msdn.microsoft.com/en-us/library/system.datetime.date(v=vs.110).aspx) property as said [here](http://stackoverflow.com/a/6592180/5095502): `startDate.Date == date.Date`. At the moment you are comparing the entire date AND time of the two "dates". — Quantic, May 10 '17 at 18:46
What is `date`? Also, no need to explicitly return `true` or `false`; just do `return (startDate == date)` directly, it's already a Boolean value. — EJoshuaS - Stand with Ukraine, May 10 '17 at 19:08

Timon Post · Accepted Answer · 2017-05-10T19:01:13.803

I don't now exactly what your code does but I suggest you try to see if there are any dates in a collection that match with a given date (see example 2).

Or if you are trying to get the elements that match a given date use example 1

      // example date
       DateTime date = new DateTime(2005,4,10);
      // data collection
      List<QueryRow> queryResult = App.StorageRepository.Query("appointments_appointment");

(Example 1 Where())

Use where to check where the date of QueryRow is equal to the given date. If it does return that QueryRow.

       IEnumerable<QueryRow> results = queryResult.Where(item => Convert.ToDateTime(item.Document.GetProperty("startDate")) == date)

       // loop the result items that matched the search result
       foreach (QueryRow result in results)
       {
           // do something with the row
       }

(Example 2 Any())

Check if the given date exists in collection. By using any it will check if there are any matching items with the date that is equal to the given date. If thre is on it will return true else false.

  bool dateExists = queryResult.Any(item => Convert.ToDateTime(item.Document.GetProperty("startDate")) == date);

No you can't debug lamda expressions inside Linq method. But you can check the result what it is giving back. And if you are not sure if the DateTime is the same witch you are trying to compare, than look at the input and see how that is formatted and check what formatted date `Document.GetProperty("startDate")` returns. — Timon Post, May 10 '17 at 19:04
@TimonPost *"No you can't debug lamda expressions inside Linq method"* -- i may be misunderstanding you, but I put breakpoints in lambdas all the time. — 15ee8f99-57ff-4f92-890c-b56153, May 10 '17 at 19:55

How to use multi condition in where of list c#

1 Answers1