问题

"ImplicitUsings" 功能允许代码省略标准命名空间的 using 语句。我需要分析一个随机的源文件，可能不知道适当的包含项集合。在 C# 10 中，可以隐式地包括一组标准命名空间，如帮助主题所述。是否有一种方式可以在创建编译时使用标准命名空间？

using System.Diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

var sourceText = "class C{" +
    "public void M(){" +
    " Console.Write(123);" +
    "}}";
var syntaxTree = CSharpSyntaxTree.ParseText(sourceText);

var coreReferences =
    ((string)AppContext.GetData("TRUSTED_PLATFORM_ASSEMBLIES"))
    .Split(Path.PathSeparator)
    .Select(p => MetadataReference.CreateFromFile(p));
var compilation = CSharpCompilation.Create("MyAnalysis")
    .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
    .AddReferences(coreReferences)
    .AddSyntaxTrees(syntaxTree);

var diagnostics = compilation.GetDiagnostics();
Debug.Assert(diagnostics.Length == 0);
// diagnostics = "error CS0103: The name 'Console' does not exist in the current context"

为了澄清上面的示例，我正在编译 sourceText 变量中的源代码。diagnostics 变量包含了 Console 不存在的错误。如果在上面的 sourceText 中添加 "using System"，则代码将无错误编译。是否有一种方式可以启用 Implicit Usings 功能，以便编译可以从标准命名空间中解析符号？

using System.Diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

var sourceText = "class C{" +
    "public void M(){" +
    " Console.Write(123);" +
    "}}";
var syntaxTree = CSharpSyntaxTree.ParseText(sourceText);

var coreReferences =
    ((string)AppContext.GetData("TRUSTED_PLATFORM_ASSEMBLIES"))
    .Split(Path.PathSeparator)
    .Select(p => MetadataReference.CreateFromFile(p));
var compilation = CSharpCompilation.Create("MyAnalysis")
    .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
    .AddReferences(coreReferences)
    .AddSyntaxTrees(syntaxTree);

var diagnostics = compilation.GetDiagnostics();
Debug.Assert(diagnostics.Length == 0);
// diagnostics = "error CS0103: The name 'Console' does not exist in the current context"

答案1

得分: 1

不是隐式使用，但你可以通过使用 CSharpCompilationOptions 类的 WithUsings 方法，将使用项添加到你的编译中。

答案2

得分: 0

Based on your request, here's the translated code portion:

根据建议，我正在尝试通过创建与特定已知SDK对应的全局usings文件来寻找可能的解决方案。可能会在项目文件中查找SDK或使用默认值。例如，对于Microsoft.NET.Sdk，我创建了以下文件（Microsoft.NET.Sdk.usings.cs）：

global using System;
global using System.Collections.Generic;
global using System.IO;
global using System.Linq;
global using System.Net.Http;
global using System.Threading;
global using System.Threading.Tasks;

有一篇[文档][1]描述了标准SDK的默认命名空间。然后，我可以加载它并解析为附加的语法树，以消除编译错误。有关不必要的using指令的警告。完整的代码如下：

using System.Diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

var sourceText = "class C{" +
    "public void M(){" +
    " Console.Write(123);" +
    "}}";
var syntaxTree = CSharpSyntaxTree.ParseText(sourceText);

var globalUsings = File.ReadAllText("Microsoft.NET.Sdk.usings.cs");
var usingsTree = CSharpSyntaxTree.ParseText(globalUsings);

var coreReferences =
    ((string)AppContext.GetData("TRUSTED_PLATFORM_ASSEMBLIES"))
    .Split(Path.PathSeparator)
    .Select(p => MetadataReference.CreateFromFile(p));
var compilation = CSharpCompilation.Create("MyAnalysis")
    .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
    .AddReferences(coreReferences)
    .AddSyntaxTrees(usingsTree, syntaxTree);

var diagnostics = compilation.GetDiagnostics();
Debug.Assert(!diagnostics.Any(d => d.Severity == DiagnosticSeverity.Error);

<details>
<summary>英文:</summary>

Based on suggestions I&#39;m pursuing a possible solution by creating a global usings file(s) corresponding to specific known SDK(s). Will probably look up SDK in the project file or use a default. For example, for Microsoft.NET.Sdk I created the following file (Microsoft.NET.Sdk.usings.cs):

    global using System;
    global using System.Collections.Generic;
    global using System.IO;
    global using System.Linq;
    global using System.Net.Http;
    global using System.Threading;
    global using System.Threading.Tasks;

There is a [document][1] describing default namespaces for standard SDK(s). Then I can load it and parse as an additional syntax tree getting rid of the compilation error. There are warnings about unnecessary using directives. The complete code is this:

    using System.Diagnostics;
    using Microsoft.CodeAnalysis;
    using Microsoft.CodeAnalysis.CSharp;
    
    var sourceText = &quot;class C{&quot; +
        &quot;public void M(){&quot; +
        &quot; Console.Write(123);&quot; +
        &quot;}}&quot;;
    var syntaxTree = CSharpSyntaxTree.ParseText(sourceText);
    
    var globalUsings = File.ReadAllText(&quot;Microsoft.NET.Sdk.usings.cs&quot;);
    var usingsTree = CSharpSyntaxTree.ParseText(globalUsings);
    
    var coreReferences =
        ((string)AppContext.GetData(&quot;TRUSTED_PLATFORM_ASSEMBLIES&quot;))
        .Split(Path.PathSeparator)
        .Select(p =&gt; MetadataReference.CreateFromFile(p));
    var compilation = CSharpCompilation.Create(&quot;MyAnalysis&quot;)
        .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
        .AddReferences(coreReferences)
        .AddSyntaxTrees(usingsTree, syntaxTree);
    
    var diagnostics = compilation.GetDiagnostics();
    Debug.Assert(!diagnostics.Any(d =&gt; d.Severity == DiagnosticSeverity.Error));


  [1]: https://learn.microsoft.com/en-us/dotnet/core/project-sdk/overview#implicit-using-directives

</details>