Dim frmc As New frmContainer()
frmc.iUID = "1"
frmc.Show()
Me.Close()

Public Class frmContainer
    Private G_iUID As String
    Public Property iUID() As String
        Get
            Return G_iUID
        End Get
        Set(ByVal value As String)
            G_iUID = value
        End Set
    End Property
 
    Public Sub New()
        Me.InitializeComponent()
 
        Me.TextBox1.Text = G_iUID
    End Sub
End Class