push to array vb.net 2008

the message was variable j is used before it have been assigned value.If in php 开发者_开发技巧language, it's not a problem at all.

Dim j() As String
        Dim i As Integer
        If (i = 1) Then
            j(0) = "x"
        Else
            j(0) = "d"
        End If

in php language,it's not a problem at all.

php doesn't use real arrays. A real array is a contiguous block of memory. Php uses a collection type with array-like semantics. They call it an array, but it's not really. Collections seldom make the same kind of guarantees about continuity because of performance problems caused when the collection grows at runtime.

If you want php-style "arrays" in .Net, you need to do the same thing php does and use a collection. The System.Collections.Generics.List<T> type works pretty well. Then you can append to the List by using its .Add() method or using the collection initializer syntax demonstrated below (requires Visual Studio 2010):

Dim i As Integer = 1
Dim j As New List(Of String) From { If(i = 1, "x","d") }

We can forgive php it's naming lapse, though, as real arrays should be used sparingly. A collection is almost always more appropriate.