I’ve been doing a lot of development using Visual Basic in the past couple of
months and there are some interesting features in the language which may or may not
be very well known. Features that don’t have an equivalent in C#.
Default values for auto implemented properties.
Visual Basic support the option of setting a default value for a property, like you
would in a field.
Public
Property MyProp AsInteger =
42
MSDN:
Auto-Implemented Properties
Key properties in anonymous types
By defining properties in anonymous types as key properties, you can enable specific
behavior for the equality behavior of these types. When an anonymous type contains
key properties, then for both the Equals and the GetHashCode overridde is generated
based on these key properties. Additionally the key properties are readonly, where
normal properties are read/write.
Dim
one
= NewWith {.Name
= "one", Key .No
= 1}
Dim
two
= NewWith {.Name
= "two", Key .No
= 1}
' This is true
because the key property for both instances of the same class is equal
Assert.IsTrue(one.Equals(two))
MSDN: Key
Filtered exceptions
Adding a filter to a catch expression in a try/catch block allows you to direct the
exception handling based on a condition. This is especially useful when you’re
catching a general exception, which should be handled differently based on the error
code it contains.
Try
Throw
New
COMException()
Catch
ex AsCOMExceptionWhen ex.ErrorCode
= 0
Console
.WriteLine("y
= 0")
Catch
ex AsCOMExceptionWhen ex.ErrorCode
<> 0
Console
.WriteLine("y
<> 0")
End
Try
MSDN: Try...Catch...Finally
Statement
Posted via email from Paul
van Brenk's posterous
