没有，我不认为有任何事情做到这一点。

No, I don't think there's anything which does this.

如果两个文件使用相同的编码，你不需要验证它们是有效的，你可以把它们作为二进制文件，如：

If the two files use the same encoding and you don't need to verify that they're valid, you can treat them as binary files, e.g.

using (Stream input = File.OpenRead("file1.txt"))
using (Stream output = new FileStream("file2.txt", FileMode.Append,
                                      FileAccess.Write, FileShare.None))
{
    input.CopyTo(output); // Using .NET 4
}
File.Delete("file1.txt");

请注意，如果 FILE1.TXT 包含字节顺序标记，你应该跳过这首以避免它 FILE2.TXT 的中间。

Note that if file1.txt contains a byte order mark, you should skip past this first to avoid having it in the middle of file2.txt.

如果你不使用.NET 4，你甚至可以使用扩展方法写你自己的 Stream.CopyTo ...相当于使交接无缝的：

If you're not using .NET 4 you can write your own equivalent of Stream.CopyTo... even with an extension method to make the hand-over seamless:

public static class StreamExtensions
{
    public static void CopyTo(this Stream input, Stream output)
    {
        if (input == null)
        {
            throw new ArgumentNullException("input)";
        }
        if (output == null)
        {
            throw new ArgumentNullException("output)";
        }
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
        {
            output.Write(buffer, 0, bytesRead);
        }
    }
}