VB.NET ToString Overrides ExampleUse an Overrides Function for ToString. Allow a Class to print information when ToString is called.
ToString is often useful in VB.NET programs. It allows us to provide a custom ToString function on a VB.NET class. By using an Overrides ToString function, we specify how an instance renders itself as a String.
Example. This program introduces the Perl class. This class, by default, inherits from the Object class. On the Object class (not shown) there exists an Overridable Function ToString.
Class The Perl class here provides the implementation that overrides ToString.
Object When Perl is used as an Object, its custom ToString implementation is still used.
New When we construct the Perl instance, its fields are set to 2 and 3. It is passed to the Console.WriteLine subroutine as an Object.
Console In Console.WriteLine, the ToString function is called on that Object. The Overrides Function ToString implementation is used.
Discussion. In the VB.NET language, we see Overridable functions and Overrides functions. These are semantically equivalent to virtual and override methods in the C# language. They have the same meaning.
Opinion The term "overridable" may be a clearer description of a virtual function. The term virtual is less obvious.
VB.NET program that overrides ToString
Module Module1 Class Perl Dim _a As Integer Dim _b As Integer Public Sub New(ByVal a As Integer, ByVal b As Integer) _a = a _b = b End Sub Public Overrides Function ToString() As String Return String.Format("[{0}, {1}]", _a, _b) End Function End Class Sub Main() Dim p As Perl = New Perl(2, 3) Console.WriteLine(p) End Sub End Module
[2, 3]
Summary. We looked at how you can provide the ToString function in your VB.NET program. This function returns a String. You can use any logic you wish to construct the String. It should use the Overrides modifier.
And This will cause it to be used as the implementation for less derived type references such as Object.
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