Creating an application similar to Notepad - how do I populate data of a user control wihout using-CodePudding

I'm a WPF beginner and it's kind of hard to wrap my head around so many new concepts so fast (I have a deadline for this project, it is homework), including the MVVM design pattern.

So I need to create an app similar to Notepad .

Each file should be opened in a new tab. I thought I might use an UserControl for that. (I've looked into it, and it seems a good choice)

The problem is that I don't know how to load the data from a file.

Here's my code: MainWindow.xaml

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1.ViewModel"
        mc:Ignorable="d"
        Title="Notepad-- - Octavian Niculescu" Height="450" Width="800">
    <Window.DataContext>
        <local:MainCommands/>
    </Window.DataContext>
    <Grid>
        <DockPanel>
            <Menu DockPanel.Dock="Top">
                <MenuItem Header="_File">
                    <MenuItem Header="_New" />
                    <MenuItem Header="_Open"
                              Command="{Binding Path=OpenFile}"/>
                    <MenuItem Header="_Save" />
                    <MenuItem Header="_Save as" />
                    <Separator />
                    <MenuItem Header="_Exit" />
                </MenuItem>
                <MenuItem Header="_Search">
                    <MenuItem Header="_Find" />
                    <MenuItem Header="_Replace" />
                    <MenuItem Header="_Replace all" />
                    <Separator />
                    <MenuItem Header="_Exit" />
                </MenuItem>
                <MenuItem Header="_Help">
                    <MenuItem Header="_About" />
                    <Separator />
                    <MenuItem Header="_Exit" />
                </MenuItem>
            </Menu>
            <Menu DockPanel.Dock="Top"/>
        </DockPanel>
    </Grid>
</Window>

FileTab.xaml

<UserControl x:Class="WpfApp1.view.FileTab"
             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" 
             xmlns:local="clr-namespace:WpfApp1.view"
             mc:Ignorable="d" 
             d:DesignHeight="420" d:DesignWidth="800">
    <Grid>
        <TextBox AcceptsReturn="True" Name="FileContent"/>
        <TextBlock HorizontalAlignment="Left" Margin="29,11,0,0" Text="FileName.txt" TextWrapping="Wrap" VerticalAlignment="Top"/>
    </Grid>
</UserControl>

MainCommands.cs (where I have the ICommands for the buttons)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Windows.Input;
using WpfApp1.ViewModel;
using WpfApp1.auxiliar;

namespace WpfApp1.ViewModel
{
    class MainCommands : INotifyPropertyChanged
    {
        private ICommand _openFile;
        public ICommand OpenFile
        {
            get
            {
                if (_openFile == null)
                {
                    _openFile = new RelayCommand(Commands.OpenFileFunc);
                }
                return _openFile;
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }
}

and Commands.cs where I have the function for opening a file

using System;
using System.Collections.Generic;
using System.Text;
using WpfApp1.view;

namespace WpfApp1.auxiliar
{
    static class Commands
    {
        public static void OpenFileFunc(object parameter)
        {
            Microsoft.Win32.OpenFileDialog openFileDlg = new Microsoft.Win32.OpenFileDialog();

            Nullable<bool> result = openFileDlg.ShowDialog();
if (result == true)
    {
        user control textblock = openFileDlg.FileName;
        user control textbox = System.IO.File.ReadAllText(openFileDlg.FileName);
    }
        }
    }
}

The dialog opens. It works fine. But now I have to bind "user control textblock" and "user control textbox" to the data, and I don't know how to do it. I don't want (and I'm also not allowed) to use code behind.

Here's my folder structure, if it matters.

My question is how do I populate those two fields from the FileTab user control with the data from that if block from Commands.cs?

Thanks.

CodePudding user response：

You should have some view models in your viewmodel folder something like a MainWindowViewModel and a FileTabViewModel. Those view models should have properties that the respective views bind to. One way to approach this would be

FileTabVM:

namespace WpfApp1.ViewModel
{
    class FileTabViewModel : INotifyPropertyChanged
    {
        ...

        public string FileContent { ... }
        public string FileName { ... }

       ...
    }
}

MainWindowVM:

namespace WpfApp1.ViewModel
{
    class MainWindowViewModel : INotifyPropertyChanged
    {
        ...

        public ObservableCollection<FileTabViewModel> FileTabs { ... }

        ...
    }
}

Then put your open command logic in the MainWindowVM, then use that to create an instance of a FileTabVM with the data it needs.

Here's a good blog post if you need a more detailed guide.