Hello,

I'm trying to make a map editor so I need to give my map data. But when I try to read/write the data I'll get an error
"Object reference not set to an instance of an object." I won't get a message box what tells me '1'.

Code:
    Private Sub ToolStripButton1_Click(sender As System.Object, e As System.EventArgs) Handles ToolStripButton1.Click
        Dim m As New Map
        m.Layer.Ground.Tile(5, 5).Data = 1
        MsgBox(m.Layer.Ground.Tile(5, 5).Data.ToString)
    End Sub
Code:
Public Class Map

    Public Layer As Layerrec

    Public Structure Layerrec

        Public Ground As Layer

    End Structure


End Class
Code:
Public Class Layer

    Public Tile(10, 10) As Tile

End Class
Code:
Public Class Tile

    Public Data As Integer


End Class
what am I doing wrong?