[dotnet-sdk-8.0.100-alpha.1.22619.1] System.IndexOutOfRangeException: 'Index was outside the bounds of the array.' exception thrown when OpenFileDialog.Multiselect=true

.NET version

.NET SDK:
Version:   8.0.100-alpha.1.22619.1
Commit:    8750a90545
Runtime Environment:
OS Name:     Windows
OS Version:  10.0.19045
OS Platform: Windows
RID:         win10-x64
Base Path:   C:\Program Files\dotnet\sdk\8.0.100-alpha.1.22619.1\

Host:
 Version:      8.0.0-alpha.1.22605.1
 Architecture: x64
 Commit:       1a37caf773

.NET SDKs installed:
  8.0.100-alpha.1.22619.1 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.0-alpha.1.22615.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.0-alpha.1.22605.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 8.0.0-alpha.1.22614.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

Verify Scenarios: 1). Windows10 21H2 x64+dotnet-sdk-8.0.100-alpha.1.22621.5: Fail 2). Windows10 21H2 x64+dotnet-sdk-8.0.100-alpha.1.22619.1: Fail 3). Windows10 21H2 x64+dotnet-sdk-8.0.100-alpha.1.22616.7: Fail 4). Windows10 21H2 x64+dotnet-sdk-7.0.101: Pass

Issue description

When testing the 3rd Party Apps with .NET 8 runtime, System.IndexOutOfRangeException: ‘Index was outside the bounds of the array.’ exception thrown when OpenFileDialog.Multiselect=true

Application Name: paint.netcore, XamlViewer OS: Windows 10 21H2 CPU: X64 .NET Build Number: dotnet-sdk-8.0.100-alpha.1.22619.1

App or App Source checking at : https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1709145

Steps to reproduce

Repro steps: The machine only has 8.0 installed. And DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX=2 is set.

1. Copy paint.net app to local machine.
2. Launch paintdotnet.exe.
3. Click File > Open.
4. Select one .png file, click Open button

Expected Result: The png file will be opened in paint.net app successfully.

Actual Result: Open failed and app crashed with following error (The crash log file pdncrash.1.log ):

Minimal Repro sample: Minimal repro sample attached. OpenFileDemo.zip

1. Create a .NET 7.0 WinForm app.
2. Add following code in Form1.cs file:

 public Form1()
        {
            InitializeComponent();
            openFileDialog1 = new OpenFileDialog();

            selectButton = new Button()
            {
                Size = new Size(100, 20),
                Location = new Point(15, 15),
                Text = "Select file"
            };
            selectButton.Click += new EventHandler(selectButton_Click);
            Controls.Add(selectButton);
        }

        private Button selectButton;
        private OpenFileDialog openFileDialog1;


        private void selectButton_Click(object sender, EventArgs e)
        {

            openFileDialog1.Multiselect = true; //This line of code will cause the exception

            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                try
                {

                    var filePath = openFileDialog1.FileName;

                }
                catch (Exception ex)
                {
                    MessageBox.Show($"Security error.\n\nError message: {ex.Message}\n\n" +
                    $"Details:\n\n{ex.StackTrace}");
                }
            }
        }

1. Build the project.
2. Change the runtimeconfig to let the app run against with .NET 8.0.100-alpha.1.22619.1:

{
  "runtimeOptions": {
    "tfm": "net7.0",
    "frameworks": [
      {
        "name": "Microsoft.NETCore.App",
        "version": "8.0.0-alpha.1.22605.1"
      },
      {
        "name": "Microsoft.WindowsDesktop.App",
        "version": "8.0.0-alpha.1.22614.1"
      }
    ]
  }
}

1. Press F5 to launch the sample app.
2. Click Select button and select a file to open it.

Excepted Result: No exception thrown.

Actual Result: This exception is thrown in code:

Findings: This issue only occurs when Multiselect=true for OpenFileDialog. If we remove Multiselect=true from source code, this issue will go.

@dotnet-actwx-bot @dotnet/compat

[Junjun-zhao]

Verified with dotnet-sdk-8.0.100-alpha.1.23077.6, this issue has been fixed.

[Nora-Zhou01]

Verified with .NET SDK 8.0.100-alpha.1.23068.16 build from main branch, this issue is fixed that the png file will be opened in paint.net app successfully.