Public Property PointCoordinates() As Vector3
Get
    Dim x As Single = 0, y As Single = 0, z As Single = 0
    Single.TryParse(xcor.Text, x)
    Single.TryParse(ycor.Text, y)
    Single.TryParse(zcor.Text, z)

    Return New Vector3(x, y, z)
End Get
Set(value As Vector3)
    xcor.Text = value.X.ToString()
    ycor.Text = value.Y.ToString()
    zcor.Text = value.Z.ToString()
End Set

Dim vectorlist as New List(Of Vector3)   'instantiate a new generic list of type Vector3
Dim vectorvariable as New Vector3(x,y,z) 'instantiate your new Vector3 structure
vectorlist.Add(vectorvariable)           'add the newly created Vector3 structure to your list

ForEach vectoritem in vectorlist
  MessageBox.Show(String.Format("X: {0}, Y: {1}, Z: {2}",vectoritem.X, vectoritem.Y, vectoritem.Z))
Next

For i As Integer = 0 to vectorlist.Count-1
  MessageBox.Show(String.Format("X: {0}, Y: {1}, Z: {2}",vectorlist(i).X, vectorlist(i).Y, vectorlist(i).Z))
Next

Public Coordinates As New List( Of Vector3 );

Coordinates.Add( PointCoordinates )

Imports System.Collections.Generic