Why does Clipboard.SetData put extra junk in the clipboard data? And how can I get it to stop?

Raymond Chen November 30, 2018 Nov 30, 2018 11/30/18

One of the ways of putting data on the clipboard is with the System.Windows.Forms.Clipboard object. There are methods for putting text on the clipboard in one of a few the standard text formats. And if you use the Clipboard.Set­Data method, you can place data on the clipboard with a custom format name. But when you use Clipboard.Set­...

Taking advantage of the ordering guarantees of the LINQ GroupBy method

Raymond Chen November 29, 2018 Nov 29, 2018 11/29/18

A customer wanted to group a set of data by one field, and within each group, sort the data by another field, and then sort the groups by that second field. For example, given the following data set: We group by name: And then we sort each person's time, shortest first. And then we sort the people by their best time. Charles's best time...

What happens if I mutate a string in a p/invoke?

Raymond Chen November 28, 2018 Nov 28, 2018 11/28/18

When it comes time to p/invoke to a Win32 function that writes to a string buffer, everybody uses a StringBuilder class to receive the string. But could we just use a string? I mean, we can still allocate a buffer for the string and then ask Win32 to fill the buffer. I mean, sure C# strings are immutable, but that just means that you can't ...

Nifty trick: Combining constructor with collection initializer

Raymond Chen November 27, 2018 Nov 27, 2018 11/27/18

C# provides a number of ways of initializing collections. If a collection has a single-parameter Add method, you can add items into the collection as part of initialization: Note that if you do not provide an argument list after the type, one will be provided for you, namely (). If a collection has a multi-parameter Add method, you can add ...

What’s up with Code Analysis rule CA2202: Do not dispose objects multiple times?

Raymond Chen November 26, 2018 Nov 26, 2018 11/26/18

You thought you'd be able to make it through the entire year without suffering through a CLR Week. And you almost made it. But here it is. Ha ha. There's no theme for this week; it's just a collection of random CLR-related articles. We begin with one of the more frustrating Code Analysis rules. Rule CA2202: Do not dispose objects multiple ...

The default number of threads in an I/O completion port is the number of processors, but is that logical or physical processors?

Raymond Chen November 23, 2018 Nov 23, 2018 11/23/18

The Create­Io­Completion­Port function lets you specify how many concurrent threads can be processing work from the completion port. But if you pass a value of 0 for Number­Of­Concurrent­Threads, "the system allows as many concurrently running threads as there are processors in the system." Are these physical ...

How can I make a dialog box right-to-left at runtime?

Raymond Chen November 22, 2018 Nov 22, 2018 11/22/18

A customer had a program that decided at runtime what language to use for its user interface. The customer was having trouble getting the program's dialog boxes to show up with right-to-left layout when necessary. We are setting the WS_EX_LAYOUT­RTL extended style in the dialog box's WM_INIT­DIALOG message handler, but what we're ...

Trying to allocate the same virtual address in multiple processes

Raymond Chen November 21, 2018 Nov 21, 2018 11/21/18

A customer wanted to know if it is possible to allocate shared memory at the same virtual address in multiple processes. The short answer is that you can try to map a shared memory block at a specific address by using the Map­View­Of­File­Ex function, but there is no guarantee that the desired address will be available. You ...