class vb.net

Question

i had create a class as follow Public Class keyword Public _name As String Public _count As Integer Public _docPoint As Integer() Public _SQLPoint As Integer End Class as global variable i wish to create an array of key1 inherits from keyword which still not sure about it's length thus i write this. Dim key1 As keyword() key1(0) = New keyword key1(0)._name =  However when i run this program in vb.net the following error message display Object reference not set to an instance of an object at line 170 which is line 170: key1(0) = New keyword May anyone help me on this problem your help is kindly appreciate.....:)

junmarcs17 · Answer

i suggest that you make use of dynamic arrays and then resize your array every time another element is added. ex. Dim Key1() as New Keyword() Dim noOfElements as Long = 0 When an element is added .... Redim Preserve Key1(noOfElements +=1) then assign values to a new array element... the preserve keyword tells the compiler to retained the old values/elements in the array while resizing.

MythicalMe · Answer

Yes. Create an array of type integer and pass that instead. Your solution worked because you overloaded the keyword.new method. That gave the compiler a reference to your class.

shinyiwong · Answer

hi thanks for ur reply...i had try another way and this is the success code Public Class keyword Public _name As String Public _count As Integer Public _docPoint As Integer() Public _SQLPoint As Integer //default contructor public sub new() end sub public sub new (ByVal name As string ByVal count As Integer ByVal doc As Array ByVal sql as Integer) _name = name _count = count _docPoint = doc _SQLPoint = sql end sub End Class Dim key1(5) As keyword // at least must create length of 1 and re-allocate again later during run time Dim index As Integer For index = 0 To 4 key(index) = New keyword Next key(0) = New keyword(  21{11}3).............................line a but i m now facing another problem...line a error comma ')' or valid expression continuation expected i thk i should not pass array in {1 1} format...am i right? nyone can help? thanks...

MythicalMe · Answer

Not sure what exactly is happening but I suspect that the compiler is confused. Try narrowing the scope of keyword. for example: Dim key1 as Me.keyword() key1(0) = New Me.keyword