The return value of method Clipboard.GetImage() is null in the .NET Core 3.0 winforms application

OS: RS3 X64 VS: Visual Studio 2019 Version 16.0.0.0 Preview 4.0 [28625.133.d16.0] .NET SDK: .NET Core 3.0 3.0.100-preview4-10523 from master branch

More Info: In .NET framework application, the return value is correct .

Steps to Reproduce:

1. Create a Winforms .Net Core application by command: dotnet new winforms –o “xxx”
2. Write code to Form1.cs using System.Drawing.Imaging; Image actual = null; Metafile expected = new Metafile(@"D:\MS.emf"); Clipboard.SetImage(expected); actual = Clipboard.GetImage();
3. Debug the application (\\mlangfs1\public\Winforms\v-jiaol\bug\MetaFileIssue.zip)

Actual: When debugging to actual = Clipboard.GetImage(), the result of actual is null.

Expected: When debugging to actual = Clipboard.GetImage(), the result of actual should be a System.Drawing.Imaging.Metafile object.

[weltkante]

I’d expect SetImage to throw an exception (unless you want to support write-only semantics for metafiles), ContainsImage return false and GetImage return null (to be consistent with other Get-methods when no data of the appropriate format is present)

Current behavior:

• SetImage with a metafile succeeds
• ContainsImage returns true
• GetImage returns null

IMHO thats broken. Do you want to reopen or should I file new issues? In particular the fact that ContainsImage returns true but GetImage returning no image is going to be confusing, if metafiles are no longer supported by design then ContainsImage should return false.

[asklar]

@russkie @merriemcgaw Hey Merrie, could you please clarify the context for dropping support for WMF/EMF? This is a format that’s widespread and widely used (e.g. both within Windows and by Office apps). Removing this functionality seems problematic, I’d like to understand what security we are gaining from this, when the Win32 API is still available. Moreover, the current state is broken because when you enumerate the formats, metafile is in there but when you ask for it, you get back null, which is a violation of the API contract.