How can I access a page's content inside a frame?

Question

I have a frame inside mainwindow, inside it there\'s a page with panels and various contents. The mainwindow decides wich page to load, and then must interact with their content

Answer 1

OK. So first, I think you might be going about this the wrong way to start. Check out this project. http://www.wpfsharp.com/2011/04/05/navigation-and-pages-using-model-view-viewmodel-mvvm/

Try this example:

MainWindow.xaml

<Window x:Class="Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525"
        Loaded="Window_Loaded"
        >
    <Grid>
        <Frame Name="MainFrame" Source="/Login.xaml"></Frame>
    </Grid>
</Window>

MainWindow.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;

namespace Test
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            var a = MainFrame.Content as Page;
            var grid = a.Content as Grid;
            var textBlock = grid.Children[0];
            // bla bla, you logged in
            MainFrame.Source = new Uri("/Home.xaml", UriKind.Relative);
            var b = MainFrame.Content as Page; // Still Login.xaml
            MainFrame.ContentRendered +=MainFrame_ContentRendered;
        }

        private void MainFrame_ContentRendered(object sender, EventArgs e)
        {
            var b = MainFrame.Content as Page; // Is now Home.xaml
        }
    }
}

Login.xaml

<Page x:Class="Test.Login"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      mc:Ignorable="d" 
      d:DesignHeight="300" d:DesignWidth="300"
    Title="Login">

    <Grid>
        <TextBlock>This is a sample login page.</TextBlock>
    </Grid>
</Page>