Object reference not set to an instance of an object error

hello, i also get the "System.NullReferenceException: Object reference not set to an instance of an object" in my code

i declare two classes:

Code:

Public Class Boardsquare
        Public Occupied As Boolean
        Public Selected As Boolean
        Public Content As New Piece
        Sub New()
            Occupied = Nothing
            Selected = Nothing
            Content = Nothing
        End Sub
        Public Sub Clear()
            Occupied = False
            Selected = False
            Content.Clear()
        End Sub
    End Class

    Public Class Piece
        Public PcTeam As String
        Public PcName As String
        Public PcCode As String
        Public PcKills As Integer
        Public PcXCoor As Integer
        Public PcYCoor As Integer
        Sub New()
            PcCode = " "
            PcName = " "
            PcTeam = " "
            PcKills = 0
        End Sub
        Public Sub Clear()
            PcTeam = " "
            PcName = " "
            PcCode = " "
            PcKills = 0
            PcXCoor = -2
            PcYCoor = -2
        End Sub
    End Class

and declare a TWO DIMENSIONAL variable of type "Boardsquare"

Code:

 Public board(,) As Boardsquare = New Boardsquare(8, 8) {}

but when i call the function to assign values to board:

Code:

        While ctx < 8
            While cty < 8

                board(ctx, cty).Content.PcCode = " "

                board(ctx, cty).Content.PcName = " "

                board(ctx, cty).Content.PcTeam = " "

                board(ctx, cty).Content.PcKills = 0

                cty = cty + 1
            End While
            ctx = ctx + 1
        End While

i get this error: "System.NullReferenceException: Object reference not set to an instance of an object."

i use two dimensional arrays since im building an 8x8 game board.

please help

Re: Object reference not set to an instance of an object error

Creating array will not instantiate each object held by each index of the array. After creation of array , you have to instatiate each object separatly in each index like:

Public board(,) As Boardsquare = New Boardsquare(8, 8) {}

board(0,0) = new Boardsquare()

board(0,1) = new Boardsquare()

.... so on. Of course you can use a loop.

Re: Object reference not set to an instance of an object error

Hi Friend,

Please add the following code in your while loop(While cty < 8).

board(ctx, cty) = New Boardsquare()
board(ctx, cty).Content = New Piece()

Now it will work fine..

Thanks.

Re: Object reference not set to an instance of an object error

thanks adeelehsan and sudhalaksh. great help