Call a method in a parent from a child user control - VB.NET/WPF

Is it possible to call a method from a loaded user control?

MainWindow.xaml.vb loads user control Login.Xaml.vb.  Login.Xaml.vb has a button on it.  When that button is clicked, I want the method MainWindow.LoadUC(UserControl) to run.

This is my MainWindow.Xaml code:

Imports System.IO
Imports Microsoft.PointOfService
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.Sql
Imports System.Net.NetworkInformation

Class MainWindow
    Public Sub MainWindow()

        InitializeComponent()
    End Sub

    Public Sub Window_Loaded()
        LoadLogin()
    End Sub

    Public Sub Load_Login()

    End Sub

    Public Sub btnAdmin_Click()

    End Sub

    Public Sub btnLogOut_Click()

    End Sub

    Public Sub LoadUC(ByVal userControl As UserControl)
        mainPanel.Children.Clear()
        mainPanel.Children.Add(userControl)
    End Sub

    Private Sub LoadLogin()
        Dim LoginScreen As New Login
        'Content = LoginScreen

        mainPanel.Children.Add(LoginScreen)

    End Sub

End Class

Select allOpen in new window

And the Login User Control code is:

Public Class Login
    Public uc As UserControl


    Public Sub numberclick()
        MsgBox("Number Click")
    End Sub

    Public Sub Login()

    End Sub
    Public Sub enterclick() Handles btnZero_Copy9.Click
        MsgBox("Number Click")
    End Sub
    Public Sub clearclick()
        MsgBox("Number Click")
        uc = New UC_Text
        
        'Not sure how to send "uc" back to MainWindow.
        'This is what I want to do, but doesn't work:
        MainWindow.LoadUC(uc)

    End Sub
End Class

Select allOpen in new window

Maybe there's a better way to go about it.  Basically, I need to load various user controls, and put them in the MainWindow's area, replacing the User Control that was there before.

Thanks for your help!!!