Question

I’m a complete beginner in WPF so this is probably very simple.

The following application is to launch arbitrary processes from data in a grid.

The part I am currently unsure about is how to effect the change to a Row instance that is passed into an auto-wired event handler, specifically Browse(Row row) in the model below:

XAML:

<Window x:Class="LauncherApp.Views.ShellView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:cm="clr-namespace:Caliburn.Micro;assembly=Caliburn.Micro"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBlock x:Name="Title" />
        <DataGrid AutoGenerateColumns="False" Name="dataGrid1" ItemsSource="{Binding Source}">
            <DataGrid.Columns>
                <DataGridTemplateColumn>
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Button Content="Run" cm:Message.Attach="Run($dataContext)" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTemplateColumn Header="Folder">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <WrapPanel>
                                <TextBox Text="{Binding Folder}" x:Name="Folder" />
                                <Button Content="Browse" cm:Message.Attach="Browse($dataContext)" />
                            </WrapPanel>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Binding="{Binding Command}" Header="Command"/>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>

Model:

namespace LauncherApp.ViewModels
{
    using Caliburn.Micro;
    using System.Collections.ObjectModel;
    using System.Windows;
    using System.Diagnostics;

    public class ShellViewModel : PropertyChangedBase
    {
        private string title;
        public string Title
        {
            get { return title; }
            set
            {
                if (title != value)
                {
                    title = value;
                    RaisePropertyChangedEventImmediately("Title");
                }
            }
        }

        public ShellViewModel()
        {
            Title = "Hello Caliburn.Micro";
            Source = new ObservableCollection<Row>(
                new[]
                {
                    new Row {},
                    new Row {},
                }
            );
        }

        public void Run(Row row)
        {
            Process process = new Process();
            process.StartInfo.FileName = row.Folder + row.Executable;
            process.StartInfo.Arguments = row.Arguments;
            process.Start();
        }

        public void Browse(Row row)
        {
            var dialog = new System.Windows.Forms.FolderBrowserDialog();
            System.Windows.Forms.DialogResult result = dialog.ShowDialog();
            string path = dialog.SelectedPath;

            row.Folder = path; // <-- THIS CHANGE DOES NOT MAKE IT BACK TO THE UI

        }

        public ObservableCollection<Row> Source { get; set; }
    }

    public class Row
    {
        public string Folder { get; set; }
        public string Executable { get; set; }
        public string Arguments { get; set; }
    }
}

UPDATE: Here’s the changes I made to make it work (thanks to EisenbergEffect)

Row class inherits PropertyChangeBase

public class Row : PropertyChangedBase // <-- add
{
    public string Folder { get; set; }
    public string Executable { get; set; }
    public string Arguments { get; set; }
}

Change notification after update

    public void Browse(Row row)
    {
        var dialog = new System.Windows.Forms.FolderBrowserDialog();
        System.Windows.Forms.DialogResult result = dialog.ShowDialog();
        string path = dialog.SelectedPath;
        row.Folder = path;
        row.RaisePropertyChangedEventImmediately("Folder"); // <-- add
    }

Answer 1

You need to implement INotifyPropertyChanged on Row (or inherit from Caliburn.Micro’s PropertyChangeBase) and make sure to raise the appropriate event in the property setter.