What is the C# equivalent of ChrW(e.KeyCode)?

Question

In VB.NET 2008, I used the following statement:

MyKeyChr = ChrW(e.KeyCode)

Now I want to convert the above statement into C#.

Any Ideas?

Zampino

Answer 1

Looks like the C# equivalent would be

var MyKeyChr = char.ConvertFromUtf32((int) e.KeyCode)

However, e.KeyCode does not contain a Unicode codepoint, so this conversion is meaningless.

Panache

It returns different value for code 140. In Vb Chrw(140) returns Πbut in C# it returns empty. What should be used to get same value? РAgeold

Answer 2

The quick-and-dirty equivalent of ChrW in C# is simply casting the value to char:

char MyKeyChr = (char)e.KeyCode;

The longer and more expressive version is to use one of the conversion classes instead, like System.Text.ASCIIEncoding.

Or you could even use the actual VB.NET function in C# by importing the Microsoft.VisualBasic namespace. This is really only necessary if you're relying on some of the special checks performed by the ChrW method under the hood, ones you probably shouldn't be counting on anyway. That code would look something like this:

char MyKeyChr = Microsoft.VisualBasic.Strings.ChrW(e.KeyCode);

However, that's not guaranteed to produce exactly what you want in this case (and neither was the original code). Not all the values in the Keys enumeration are ASCII values, so not all of them can be directly converted to a character. In particular, casting Keys.NumPad1 et. al. to char would not produce the correct value.

Blades

it's not the direct equivalent. The VB.Net version handles certain boundary cases that a direct cast won't (outside the range of char for example). Boundary cases to be sure but a cast is not a direct equivalent – Feola

@Jared: A fair point, I always forget about some of that extra behavior. Answer fixed. – Blades

Answer 3

The most literal way to translate the code is to use the VB.Net runtime function from C#

MyKeyChr = Microsoft.VisualBasic.Strings.ChrW(e.KeyCode);

If you'd like to avoid a dependency on the VB.Net runtime though you can use this trimmed down version

MyKeyChr = Convert.ToChar((int) (e.KeyCode & 0xffff));

Feola

The way you phrase that makes it sound like the VB.NET runtime is an entirely separate runtime environment from the C# runtime. Microsoft.VisualBasic is just a class in the BCL. Using it from a C# program doesn't really add an extra dependency; the compiler will fully quality all imported references anyway. – Blades

@Cody talking about Microsoft.VisualBasic.dll often involves walking a fine line of terms. From VB.Net's perspective it is a runtime DLL (in the docs and users minds). The language has heavy runtime dependencies on behavior in that DLL. Parts of it are simply inseparable from the underlying language semantics. But yes it can be confusing when considering terms like "the .Net runtime". Note though that C#'s 4.0 assembly for dynamic support is also referred to as the C# runtime DLL in many docs. – Feola

@Cody and yes it is just another DLL but it has a set of dependencies that many people simply don't expect from what is usually known as a language runtime. For example it depends on System.Windows.Forms and System.Management. – Feola

Answer 4

The C# equivalent of ChrW(&H[YourCharCode]) is Strings.ChrW(0x[YourCharCode])

You can use https://converter.telerik.com/ do convert between VB & C#.

Fiorenze

Answer 5

This worked for me to convert VB:

e.KeyChar = Microsoft.VisualBasic.ChrW(13)

To C#:

e.KeyChar == Convert.ToChar(13)

Callosity