Encoding.GetEncodings()不能正常工作

Question

以下代码块在C#交互式编译器上运行良好

Microsoft (R) Visual C# Interactive Compiler version 4.2.0-4.22252.24 ()
Loading context from 'CSharpInteractive.rsp'.
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> using System.Text;
> var codepages = Encoding.GetEncodings().Select(x => x.GetEncoding()).ToList();
> foreach (var cp in codepages) { Console.WriteLine($"{cp.HeaderName} {cp.EncodingName} ({cp.CodePage})"); }

输出

1. IBM037 IBM EBCDIC (US-Canada) (37)
2. IBM437 OEM United States (437)
3. IBM500 IBM EBCDIC (International) (500)
..
..
..
138. x-iscii-pa ISCII Punjabi (57011)
139. utf-7 Unicode (UTF-7) (65000)
140. utf-8 Unicode (UTF-8) (65001)

但是，每当我想在.net 6.0 winform应用程序中运行它时，

        public MainForm()
        {
            InitializeComponent();
            initView();
            cbEncodings.Items.Clear();
            var codepages = Encoding.GetEncodings().Select(x => x.GetEncoding()).ToList();
            foreach (var e in codepages)
            {
                cbEncodings.Items.Add($"{e.EncodingName} ({e.CodePage})");
            }
        }

它只列出了7个元素

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这是什么原因？

Answer 1

在代码之前添加Encoding.RegisterProvider(CodePagesEncodingProvider.Instance); (即在var codepages = Encoding.GetEncodings().Select(x => x.GetEncoding()).ToList();之前)，然后得到完整的列表。详情见https://learn.microsoft.com/en-us/dotnet/api/system.text.encoding.getencodings?view=net-6.0。