How can I access RichEditBox from one page, if it's located in another page?

Question

Hello, guys!

In my app, I have MainPage.xaml and ContentPage.xaml (note that ContentPage is not the actual ContentPage, it is just a BlankPage that I named this way). On my ContentPage.xaml I only have one element — RichEditBox. The content of the ContentPage (RichEditBox) is displayed on MainPage. I want to be able to open text files and load them to ContentPage, but the code that I have for that is in MainPage.xaml.cs, so IDE keeps showing me the error. The code:

Windows.Storage.Pickers.FileOpenPicker open = new
                   Windows.Storage.Pickers.FileOpenPicker();
                open.SuggestedStartLocation =
                   Windows.Storage.Pickers.PickerLocationId.DocumentsLibrary;
                open.FileTypeFilter.Add(".txt");
                Windows.Storage.StorageFile file = await open.PickSingleFileAsync();

                if (file != null)
                {
                    Windows.Storage.Streams.IRandomAccessStream randAccStream = await
                       file.OpenAsync(Windows.Storage.FileAccessMode.Read);

                    // Load the file into the Document property of the RichEditBox.
                    editor.Document.LoadFromStream(Windows.UI.Text.TextSetOptions.FormatRtf, randAccStream);

I thought I would be able to access the RichEditBox if I add x:FieldModifier="Public", but it didn't do anything. The IDE keeps telling me that "The name 'editor' does not exist in the current context". So, how do I access RichEditBox from MainPage.xaml.cs?

EDIT:

MainPage.xaml code:

MainPage.xaml.cs code:

using Microsoft.UI.Xaml.Controls;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel.Core;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace TestApp
{
    /// 
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// 
    /// 

    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();

        }

        private void NewTabKeyboardAccelerator_Invoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
        {
            var senderTabView = args.Element as TabView;
            senderTabView.TabItems.Add(CreateNewTab(senderTabView.TabItems.Count));
            args.Handled = true;
        }

        private void CloseSelectedTabKeyboardAccelerator_Invoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
        {
            var InvokedTabView = (args.Element as TabView);

            // Only close the selected tab if it is closeable
            if (((TabViewItem)InvokedTabView.SelectedItem).IsClosable)
            {
                InvokedTabView.TabItems.Remove(InvokedTabView.SelectedItem);
            }
            args.Handled = true;
        }

        private void NavigateToNumberedTabKeyboardAccelerator_Invoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
        {
            var InvokedTabView = (args.Element as TabView);

            int tabToSelect = 0;

            switch (sender.Key)
            {
                case Windows.System.VirtualKey.Number1:
                    tabToSelect = 0;
                    break;
                case Windows.System.VirtualKey.Number2:
                    tabToSelect = 1;
                    break;
                case Windows.System.VirtualKey.Number3:
                    tabToSelect = 2;
                    break;
                case Windows.System.VirtualKey.Number4:
                    tabToSelect = 3;
                    break;
                case Windows.System.VirtualKey.Number5:
                    tabToSelect = 4;
                    break;
                case Windows.System.VirtualKey.Number6:
                    tabToSelect = 5;
                    break;
                case Windows.System.VirtualKey.Number7:
                    tabToSelect = 6;
                    break;
                case Windows.System.VirtualKey.Number8:
                    tabToSelect = 7;
                    break;
                case Windows.System.VirtualKey.Number9:
                    // Select the last tab
                    tabToSelect = InvokedTabView.TabItems.Count - 1;
                    break;
            }

            // Only select the tab if it is in the list
            if (tabToSelect < InvokedTabView.TabItems.Count)
            {
                InvokedTabView.SelectedIndex = tabToSelect;
            }
            args.Handled = true;
        }

        private void TabView_Loaded(object sender, RoutedEventArgs e)
        {
            for (int i = 0; i < 1; i++)
            {
                (sender as TabView).TabItems.Add(CreateNewTab(i));
            }
        }

        private void TabView_AddButtonClick(TabView sender, object args)
        {
            sender.TabItems.Add(CreateNewTab(sender.TabItems.Count));
        }

        private void TabView_TabCloseRequested(TabView sender, TabViewTabCloseRequestedEventArgs args)
        {
            sender.TabItems.Remove(args.Tab);
        }

        private TabViewItem CreateNewTab(int index)
        {
            TabViewItem newItem = new TabViewItem();

            newItem.Header = $"Untitled-{index}.txt";
            newItem.IconSource = new Microsoft.UI.Xaml.Controls.SymbolIconSource() { Symbol = Symbol.Document };

            // The content of the tab is often a frame that contains a page, though it could be any UIElement.
            Frame frame = new Frame();

            frame.Navigate(typeof(ContentPage));

            newItem.Content = frame;

            return newItem;
        }

        private void MenuFlyoutItem_ClickSettings(object sender, RoutedEventArgs e)
        {
            Frame.Navigate(typeof(SettingsPage));
        }

        private void MenuFlyoutItem_ClickExit(object sender, RoutedEventArgs e)
        {
            CoreApplication.Exit();
        }

        private async void FileOpen_Click(object sender, RoutedEventArgs e)
        {
            // Open a text file. 
            Windows.Storage.Pickers.FileOpenPicker open = new
               Windows.Storage.Pickers.FileOpenPicker();
            open.SuggestedStartLocation =
               Windows.Storage.Pickers.PickerLocationId.DocumentsLibrary;
            open.FileTypeFilter.Add(".txt");
            Windows.Storage.StorageFile file = await open.PickSingleFileAsync();

            if (file != null)
            {
                Windows.Storage.Streams.IRandomAccessStream randAccStream = await
                   file.OpenAsync(Windows.Storage.FileAccessMode.Read);

                // Load the file into the Document property of the RichEditBox.
                editor.Document.LoadFromStream(Windows.UI.Text.TextSetOptions.FormatRtf, randAccStream);
            }
        }
    }
}

ContentPage.xaml code:

Accepted Answer

Hello,

Welcome to Microsoft Q&A!

Based on the code that you posted, a simple implementation is that you could define a static Current variable on ContentPage.cs which can be called from MainPage to get the ContentPage instance similar to what @Ken Tucker suggested.

ContentPage:

 public static ContentPage current { get; set; }  
  
        public ContentPage()  
        {  
            this.InitializeComponent();  
            current = this;  
        }  
  
        public void SetText(IRandomAccessStream randAccStream)  
        {  
             editor.Document.LoadFromStream(Windows.UI.Text.TextSetOptions.FormatRtf, randAccStream);  
        }

MainPage:

 ContentPage.current.SetText(Stream);

Thank you.

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Answer

You need a variable which has a reference to the displayed page with the richtextbox on it. Then you can access the richtextbox with MyPageVariable.MyRichTextBox

Answer

Based on your question, I believe you can use Xamarin.Forms ContentView. Content View allows you to create a layout that contains a single child element and is used to create reusable controls.

Refer: https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/layouts/contentview

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How can I access RichEditBox from one page, if it's located in another page?

2 additional answers