Introduction of LanguageTypeConverter.

src/CodeAnalysis.TestTools/Conversion/LanguageTypeConverter.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel;
+
+namespace CodeAnalysis.TestTools.Conversion;
+
+/// <summary>Implements a <see cref="TypeConverter"/> for <see cref="Language"/>.</summary>
+internal sealed class LanguageTypeConverter : TypeConverter
+{
+    /// <inheritdoc />
+    [Pure]
+    public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
+        => sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
+
+    /// <inheritdoc />
+    [Pure]
+    public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value) => value switch
+    {
+        null => Language.None,
+        string str => Language.Parse(str),
+        _ => base.ConvertFrom(context, culture, value),
+    };
+}

src/CodeAnalysis.TestTools/Language.cs

@@ -1,6 +1,9 @@
-namespace CodeAnalysis.TestTools;
+using System.ComponentModel;
+
+namespace CodeAnalysis.TestTools;
 
 /// <summary>Represents a (code) language.</summary>
+[TypeConverter(typeof(Conversion.LanguageTypeConverter))]
 public readonly struct Language : IEquatable<Language>
 {
     /// <summary>None.</summary>
@@ -77,7 +80,7 @@ public static Language Parse(string? str)
         {
             "" or null => None,
             "CSHARP" or "CS" or "C#" or ".CS" => CSharp,
-            "VB" or "VBNET" or "VISUALBASIC" or ".VB" => VisualBasic,
+            "VB" or "VB.NET" or "VBNET" or "VISUALBASIC" or ".VB" => VisualBasic,
             "FSHARP" or "FS" or "F#" or ".FS" => FSharp,
             "XML" or "EXTENSIBLEMARKUPLANGUAGE" or ".XML" => XML,
             _ => throw new FormatException(Messages.Language_InvalidFormat),