On remote desktop machine (Windows 11), the DataGrid (WPF C# application .Net Framework 4.7.2) event is throwing System.Reflection.TargetInvocationException.

Sharayu Mahadeorao P 0

The DataGrid event is giving the exception"System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Added item does not appear at given index '4'. " while running the code on remote desktop machine (Windows 11) but same code is not giving any exception on local machine (Windows 11).

Below is the observation:

DataGrid_Load is getting fired when remote desktop is reconnected.

Hongrui Yu-MSFT 2,465 Reputation points Microsoft Vendor

2024-07-02T02:29:05.65+00:00

Hi,@Sharayu Mahadeorao P. Welcome to Microsoft Q&A.

I have a few areas of ambiguity:

1.The program is deployed on the remote desktop, close the remote desktop, and how you observe the DataGrid_Load being executed

2.Do you turn off the remote desktop, or close the remote connection

Please share with me the complete steps and simple code example to reproduce the issue.

Sharayu Mahadeorao P 0

Hi @Hongrui Yu-MSFT ,

Thank you for your reply.

I am just closing the connection of remote desktop from my local machine. No turning-off of remote desktop machine.

Steps to reproduce the issue:

1.Take remote desktop connection

2.Run the executable

3.Select any row and keep the window as it is

4.Close the remote desktop machine connection without logging-off

5.After 2-3 min again take remote desktop connection

Issue: In log file , DataGrid_Load event is added.

Sample code is as follows:XAML file

<Window x:Class="RdpTest.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:RdpTest"        

    mc:Ignorable="d" Closed="Window_Closed"

    Title="MainWindow" Height="450" Width="800">

<Grid>

    <Grid.RowDefinitions>

        <RowDefinition Height="*"/>

        <RowDefinition Height="*"/>

    </Grid.RowDefinitions>

    <Grid>

        <DataGrid

        HorizontalAlignment="Stretch"

        Margin="10,10,0,0"

        VerticalAlignment="Top"

        Loaded="DataGrid_Loaded"            

        SelectionChanged="DataGrid_SelectionChanged"/>

    </Grid>

    <Grid Grid.Row="1">

        <DataGrid Name="SelectedItemsGrid"

        HorizontalAlignment="Stretch"

        Margin="10,10,0,0"

        VerticalAlignment="Top"/>

    </Grid>

</Grid>

</Window>

XAML.cs File

public partial class MainWindow : Window

{

    List<Grid_Doc> items;

    Model _clsModel = new Model();

    public MainWindow()

    {

        items = new List<Grid_Doc>();

        InitializeComponent();

        AddItems();

        _clsModel.PropertyChanged += _clsModel_PropertyChanged;

        Log("MainWindow Initialized");

    }

    private void _clsModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)

    {

        switch (e.PropertyName)

        {

            case "DataGridSelectedItems":

                SelectedItemsGrid.ItemsSource = _clsModel.DaraGridSelectedItems;

                Log("_clsModel_PropertyChanged");

                break;

        }

    }

    public static void Log(string logMessage)

    {

        using (StreamWriter w = File.AppendText("log.txt"))

        {

            w.Write($"{logMessage} : ");

            w.WriteLine($"{DateTime.Now.ToLongTimeString()} {DateTime.Now.ToLongDateString()}");

        }

    }

    private void AddItems()

    {

        items.Add(new Grid_Doc("Fido", 10));

        items.Add(new Grid_Doc("Spark", 20));

        items.Add(new Grid_Doc("Fluffy", 4));

        items.Add(new Grid_Doc("Rover", 100));

        items.Add(new Grid_Doc("Mister Mars", 30));

    }

    private void DataGrid_Loaded(object sender, RoutedEventArgs e)

    {

        var grid = sender as DataGrid;

        grid.ItemsSource = items;

        Log("DataGrid_Loaded");

    }

    private void DataGrid_SelectionChanged(object sender,

        SelectionChangedEventArgs e)

    {

        var grid = sender as DataGrid;

        var selected = grid.SelectedItems;

        List<Grid_Doc> _selectedItems = new List<Grid_Doc>();

        foreach (var item in selected)

        {

            var doc = item as Grid_Doc;

            _selectedItems.Add(doc);

        }

        _clsModel.DaraGridSelectedItems = _selectedItems;

        Log("DataGrid_SelectionChanged");

    }        

    private void Window_Closed(object sender, EventArgs e)

    {           

       _clsModel.PropertyChanged -= _clsModel_PropertyChanged; 

        Log("Window_Closed");

    }

}

class Grid_Doc

{

    public string Name { get; set; }

    public int Size { get; set; }

    public Grid_Doc(string name, int size)

    {

        this.Name = name;

        this.Size = size;

    }

}

Model.cs file

class Model : INotifyPropertyChanged

{

    List<Grid_Doc> _items;

    public List<Grid_Doc> DaraGridSelectedItems

        {

        get { return _items; }

        set

        {

            _items = value;

            OnPropertyChanged("DataGridSelectedItems");

        }

    }

    [NonSerialized]

    private Collection<PropertyChangedEventHandler> _Handlers = new Collection<PropertyChangedEventHandler>();

    public event PropertyChangedEventHandler PropertyChanged

    {

        add

        {

            _Handlers.Add(value);

        }

        remove

        {

            _Handlers.Remove(value);

        }

    }

    protected void OnPropertyChanged(string _strPropertyName)

    {  

        if (_Handlers != null && _Handlers.Count != 0)

        {

            for (int i = 0; i < _Handlers.Count; i++)

            {

                _Handlers[i].Invoke(this, new PropertyChangedEventArgs(_strPropertyName));

            }

        }

    }

}

Sharayu Mahadeorao P 0

Hi @Hongrui Yu-MSFT

Thanks for your reply.

The program deployed on the remote desktop and closed the remote desktop connection and after some time again take the remote desktop connection and check the log

Sample code is as follows

XAML File

<Window x:Class="RdpTest.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:RdpTest"        

    mc:Ignorable="d" Closed="Window_Closed"

    Title="MainWindow" Height="450" Width="800">

<Grid>

    <Grid.RowDefinitions>

        <RowDefinition Height="*"/>

        <RowDefinition Height="*"/>

    </Grid.RowDefinitions>

    <Grid>

        <DataGrid

        HorizontalAlignment="Stretch"

        Margin="10,10,0,0"

        VerticalAlignment="Top"

        Loaded="DataGrid_Loaded"            

        SelectionChanged="DataGrid_SelectionChanged"/>

    </Grid>

    <Grid Grid.Row="1">

        <DataGrid Name="SelectedItemsGrid"

        HorizontalAlignment="Stretch"

        Margin="10,10,0,0"

        VerticalAlignment="Top"/>

    </Grid>

</Grid>

</Window>

XAML. cs

public partial class MainWindow : Window

{

    List<Grid_Doc> items;

    Model _clsModel = new Model();

    public MainWindow()

    {

        items = new List<Grid_Doc>();

        InitializeComponent();

        AddItems();

        _clsModel.PropertyChanged += _clsModel_PropertyChanged;

        Log("MainWindow Initialized");

    }

    private void _clsModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)

    {

        switch (e.PropertyName)

        {

            case "DataGridSelectedItems":

                SelectedItemsGrid.ItemsSource = _clsModel.DaraGridSelectedItems;

                Log("_clsModel_PropertyChanged");

                break;

        }

    }

    public static void Log(string logMessage)

    {

        using (StreamWriter w = File.AppendText("log.txt"))

        {

            w.Write($"{logMessage} : ");

            w.WriteLine($"{DateTime.Now.ToLongTimeString()} {DateTime.Now.ToLongDateString()}");

        }

    }

    private void AddItems()

    {

        items.Add(new Grid_Doc("Fido", 10));

        items.Add(new Grid_Doc("Spark", 20));

        items.Add(new Grid_Doc("Fluffy", 4));

        items.Add(new Grid_Doc("Rover", 100));

        items.Add(new Grid_Doc("Mister Mars", 30));

    }

    private void DataGrid_Loaded(object sender, RoutedEventArgs e)

    {

        var grid = sender as DataGrid;

        grid.ItemsSource = items;

        Log("DataGrid_Loaded");

    }

    private void DataGrid_SelectionChanged(object sender,

        SelectionChangedEventArgs e)

    {

        var grid = sender as DataGrid;

        var selected = grid.SelectedItems;

        List<Grid_Doc> _selectedItems = new List<Grid_Doc>();

        foreach (var item in selected)

        {

            var doc = item as Grid_Doc;

            _selectedItems.Add(doc);

        }

        _clsModel.DaraGridSelectedItems = _selectedItems;

        Log("DataGrid_SelectionChanged");

    }

    //private void DataGrid_Unloaded(object sender, RoutedEventArgs e)

    //{

    //   items = null;

    //   Log("DataGrid_Unoaded");

    //}

    private void Window_Closed(object sender, EventArgs e)

    {           

       _clsModel.PropertyChanged -= _clsModel_PropertyChanged; 

        Log("Window_Closed");

    }

}

class Grid_Doc

{

    public string Name { get; set; }

    public int Size { get; set; }

    public Grid_Doc(string name, int size)

    {

        this.Name = name;

        this.Size = size;

    }

}

Model.cs

class Model : INotifyPropertyChanged

{

    List<Grid_Doc> _items;

    public List<Grid_Doc> DaraGridSelectedItems

        {

        get { return _items; }

        set

        {

            _items = value;

            OnPropertyChanged("DataGridSelectedItems");

        }

    }

    [NonSerialized]

    private Collection<PropertyChangedEventHandler> _Handlers = new Collection<PropertyChangedEventHandler>();

    public event PropertyChangedEventHandler PropertyChanged

    {

        add

        {

            _Handlers.Add(value);

        }

        remove

        {

            _Handlers.Remove(value);

        }

    }

    protected void OnPropertyChanged(string _strPropertyName)

    {  

        if (_Handlers != null && _Handlers.Count != 0)

        {

            for (int i = 0; i < _Handlers.Count; i++)

            {

                _Handlers[i].Invoke(this, new PropertyChangedEventArgs(_strPropertyName));

            }

        }

    }

}

2 answers

Michael Taylor 54,811 Reputation points

2024-07-02T02:38:57.1266667+00:00

Sounds like a race condition to me and nothing really to do with RD. However your explanation is confusing to me. The Load event wouldn't trigger when RD is closed unless something is triggering the UX to load as that event is called when the window is displayed.

Given your explanation it is my guess that you have a bad event handler. Most likely the property changed event is being raised on an object that is getting cleaned up and therefore it crashes. You cannot replicate this problem easily locally because you cannot close out your session and keep the debugger attached locally.

Please post the stacktrace that is being reported as part of this exception. Most likely you need to disconnect your event handlers before the window closes but the stack will help show that.

Also please clarify whether you're closing the window (and leaving the user connected in the session) or closing the session AND logging off the user at the same time.
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Sharayu Mahadeorao P 0 Reputation points

2024-07-02T06:59:40.9233333+00:00

Hi @Michael Taylor

Thanks for your reply.

I am running the application on the remote desktop machine and then without closing the running application, just closed the remote desktop connection without logging-off and after some time again reconnect or take remote desktop connection of the machine then observed that DataGrid_Load event is getting called.

In previous comment (reply), I have added code sample.
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Hongrui Yu-MSFT 2,465 Reputation points Microsoft Vendor

2024-07-02T08:29:44.59+00:00

Hi,@Sharayu Mahadeorao P.

Reason: When you reconnect remotely, the page will be re-rendered for you, and the triggering conditions of the Loaded event are met, so the Loaded event is executed again.

Solution: You can choose to use the Initialized event instead of the Loaded event

You can learn more about the difference between Initialized event and Loaded event. Below is their official link

Loaded event: FrameworkElement.Loaded Event (System.Windows) | Microsoft Learn

Initialized event: FrameworkElement.Initialized Event (System.Windows) | Microsoft Learn

The error you mentioned is not found in the code you provided. I guess it is caused by executing the Loaded event again. If necessary, please explain in detail.

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Hongrui Yu-MSFT 2,465 Reputation points Microsoft Vendor

2024-07-08T02:30:46.19+00:00

Hi,@Sharayu Mahadeorao P.

Is there any update to the question? Did my answer solve your problem? If so, you could accept it as the answer. It's helpful for community members with related questions.
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On remote desktop machine (Windows 11), the DataGrid (WPF C# application .Net Framework 4.7.2) event is throwing System.Reflection.TargetInvocationException.

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