Home » Tip Bank » .NET » VB.NET » String Manipulation

Language: C#
Expertise: Advanced

Feb 7, 2005

VB6 introduced the CallByName function which allows you to call a function or subroutine using the subroutine or function name stored as a string value. While this function still works in ASP.NET, you do have another option: you can use the Invoke method of the MethodInfo class. This class is a member of the System.Reflection namespace and it provides access to a method's metadata. Consider the following subroutine:

Public Sub CallMe(ByVal arg1 As String, ByVal _ 
arg2 As String)

'do something

End Sub

To call this subroutine using the Invoke method, you can use code similar to the following:

Dim SubName As String = "CallMe"

Dim arguments() As String = _
{"Hello ", "world."}

Dim PageType As Type = Page.GetType()
Dim MyMethod As System.Reflection.MethodInfo = _
PageType.GetMethod(SubName)
MyMethod.Invoke(Page, arguments)

The GetMethod method obtains information about the function and the Invoke method calls it using the argument list. This is an excellent tool to help you streamline your code—especially if you have several different functions, but you won't know which one to call until runtime.

For example, suppose you have a new, edit, and delete routine for updating database records. Instead of using an Parthasarathy Mandayam