Browse questions answered by Jon Skeet

Get two linq queries into one listbox

I need to get the values of two LINQ queries in to one listbox. Currently I have it going in to two separate listboxe's side by side so it works but is not optimal. The data is...

It sounds like you just want: var items = dataTable.Select(p => string.Format("{0} : {1}", p.NAME, p.TOTALS)); listBox1.Items.AddRange(items.ToArray()); more 9/20/2013 8:24:11 PM

C# XDocument / linq to object

How can i import xml elements to object? My code below doesn't work, it fails at the SetValue and i can't figure out why. But even then, i suspect that linq has a much cleaner...

You're asking for properties - but your type only has fields. Either make them properties, like this: public string name { get; set; } ... or use Type.GetField instead. In terms of making it prettier, I'd personally add a static... more 9/20/2013 3:27:12 PM

Convert string to Time

I have a time that is 16:23:01. I tried using DateTime.ParseExact, but it's not working. Here is my code: string Time = "16:23:01"; DateTime date = DateTime.ParseExact(Time,...

"16:23:01" doesn't match the pattern of "hh:mm:ss tt" - it doesn't have an am/pm designator, and 16 clearly isn't in a 12-hour clock. You're specifying that format in the parsing part, so you need to match the format of the existing data.... more 9/20/2013 2:42:36 PM

limit or audit the use of an interface

I have 3 assemblies: A defines an interface B references A and uses that interface C also references A how can I make sure C does not use that interface? splitting...

You could make the interface internal, and use InternalsVisibleToAttribute to allow B access to the internal members of A (by adding the attribute to A). It's very coarse-grained though - you can't do it for individual members; it's all or... more 9/20/2013 1:47:58 PM

How to test singletons in one test class?

I want to test the behavior of a singleton class with following methods: public class SomeSingleton { private final static int DEFAULT_VALUE1 = ...; private final static...

Fundamentally singletons are hard to test, precisely because of this sort of thing. You could add a clearStateForTesting method: static void clearStateForTesting() { instance = null; } ... but I'd suggest that you avoid the... more 9/20/2013 1:21:20 PM

Can't access members of a class after unboxing

I am learning advanced C#.In the following Code i am trying to do Event handling i get Error while accessing members of class sender after unboxing //Compiler is not...

This is the problem: object obj=new object(); obj=sender as Sender; The second line doesn't change the compile-time type of obj. It's still just object. (And your first line that creates a new object is completely pointless.) The... more 9/20/2013 1:07:49 PM

NullPointerException in PrintWriter[] array Java

I have a problem which i am trying to figure out for days now. Simple Code Overview(PseudoCode): 1 - When a user connects create a PrintWriter for him. 2 - Store the...

As far as I can tell, this is the problem (in Server): new Thread(new ServerHandler(klientSocket)).start(); Here you're creating a new ServerHandler. That's completely separate from the instance of ServerHandler which you're creating in... more 9/20/2013 12:40:25 PM

Assign Object array with Integer elements to Integer array

I searched the internet but didn't found any appropriate solution. In my application I've got an array of integers. I need to access (assign to) the array via reflection. The...

No, you can't cast a value which is actually a reference to an instance of Object[] to an Integer[] variable - and that's a good thing. Imagine if that were valid... consider: Object[] values = { new Integer(5), new Integer(10)... more 9/20/2013 12:18:49 PM

XPath / linq to xml: xmlns=""testNS"" results in no result

a xml file/string can be validated but yields no results if queried by XPath or linq to xml. The difference is: xmlns=""testNS"" xsi:... in the example strings. Without this...

If you're going to query elements that have namespaces using XPath or LINQ to XML, you have to specify that namespace. For example: XNamespace ns = "testNS"; var root = XElement.Parse(xmlString); return root.Descendants(ns +... more 9/20/2013 12:14:21 PM

Determining if a UTC time is within DST

In C#, given a UTC time, how can I determine whether this falls within DST in Houston, Texas, US? var utcDateTime = new DateTime(2013,1,1,0,0,0,DateTimeKind.Utc); //bool...

Get the appropriate TimeZoneInfo for Texas, then use IsDaylightSavingTime. using System; class Test { static void Main() { // Don't be fooled by the "standard" part - this is Central Time var zone =... more 9/20/2013 12:00:17 PM