尝试构建时出现 CS1003 和 CS1026 语法错误

Question

I'm not sure why I am getting this error.I am trying to build this on Visual Studio.I am new but i need to build this code.

There are my errors and code :

(30,19): error CS1003: Syntax error, '(' expected

(30,88): error CS1026: ) expected

(31,19): error CS1003: Syntax error, '(' expected

(31,51): error CS1026: ) expected

(36,23): error CS1003: Syntax error, '(' expected

(36,63): error CS1026: ) expected

(37,23): error CS1003: Syntax error, '(' expected

(37,156): error CS1026: ) expected

namespace MelonLoader.AssemblyGenerator
{
    public static class DownloaderAndUnpacker
    {
        public static void Run(string url, string targetVersion, string currentVersion, string destinationFolder, string tempFile)
        {
            if (targetVersion == currentVersion)
            {
                Logger.Log($"{destinationFolder} already contains required version, skipping download");
                return;
            }
            
            Logger.Log($"Cleaning {destinationFolder}");
            foreach (var entry in Directory.EnumerateFileSystemEntries(destinationFolder))
            {
                if (Directory.Exists(entry))
                    Directory.Delete(entry, true);
                else
                    File.Delete(entry);
            }

            Logger.Log($"Downloading {url} to {tempFile}");
            Program.webClient.DownloadFile(url, tempFile);
            Logger.Log($"Extracting {tempFile} to {destinationFolder}");
            
/*line 30*/ using var stream = new FileStream(tempFile, FileMode.Open, FileAccess.Read);
            using var zip = new ZipArchive(stream);
            
            foreach (var zipArchiveEntry in zip.Entries)
            {
                Logger.Log($"Extracting {zipArchiveEntry.FullName}");
                using var entryStream = zipArchiveEntry.Open();
                using var targetStream = new FileStream(Path.Combine(destinationFolder, zipArchiveEntry.FullName), FileMode.OpenOrCreate, FileAccess.Write);
                entryStream.CopyTo(targetStream);
            }
        }
    }
}

Answer 1

This seems to be C# 8 "using declarations"; it is possible that you have an up to date compiler available, but your csproj is configured to use down-level C#; it is possible that editing the cspoj to update or add:

<LangVersion>8</LangVersion>

(or higher, inside a <PropertyGroup> element)

would fix it.

If you can't use C# 8, then:

using (var stream = new FileStream(tempFile, FileMode.Open, FileAccess.Read))
using (var zip = new ZipArchive(stream))
{

    foreach (var zipArchiveEntry in zip.Entries)
    {
        Logger.Log($"Extracting {zipArchiveEntry.FullName}");
        using (var entryStream = zipArchiveEntry.Open())
        using (var targetStream = new FileStream(Path.Combine(destinationFolder, zipArchiveEntry.FullName), FileMode.OpenOrCreate, FileAccess.Write))
        {
            entryStream.CopyTo(targetStream);
        }
    }
}