DirectCast Function |
No
DirectCast( expression, typename )
The data item to be converted
The data type, object type, structure, or interface to which expression is to be converted
expression cast as a typename interface or object
Converts an expression to its runtime data type, if possible; otherwise , returns an error.
expression must be a reference type, typically a variable of type Object..
typename can be any data type (such as Boolean, Byte, Decimal, Long, Short, String, etc.), structure type, object type, or interface.
If the function fails, an InvalidCastException exception occurs.
In contrast to the CType function, DirectCast converts a reference type (i.e., an object) to its runtime type. For instance,
Option Strict On Imports System Public Module modMain Public Sub Main Dim oVal As Object = "a"c Dim chVal As Char = DirectCast(oVal, Char) Console.WriteLine(chVal) End Sub End Module
DirectCast can also be used to convert an object of a derived type to its base type. For example:
Option Strict On Imports System Public Class Person ' Implementation of Person End Class Public Class Worker Inherits Person ' Implementation of Worker End Class Public Module modMain Public Sub Main ' Conversion of a derived to a base type Dim oWorker As New Worker() Dim oPerson As Person = oWorker Dim oPerson As Person = DirectCast(oWorker, Person) End Sub End Module
Like most of the conversion functions, DirectCast is not actually a function in the Microsoft.VisualBasic namespace. Instead, it is similar to a Visual C++ macro; the compiler translates the function call into inline code.
The DirectCast function is new to VB .NET.
CType Function