对于复制我使用了以下代码：-

public static void Copy(string inputFilePath, string outputFilePath)
    {
        int bufferSize = 1024 * 1024;

        using (FileStream fileStream = new FileStream(outputFilePath, FileMode.OpenOrCreate, FileAccess.Write,FileShare.ReadWrite))
        //using (FileStream fs = File.Open(<file-path>, FileMode.Open, FileAccess.Read, FileShare.Read))
        {
            FileStream fs = new FileStream(inputFilePath, FileMode.Open, FileAccess.ReadWrite);
            fileStream.SetLength(fs.Length);
            int bytesRead = -1;
            byte[] bytes = new byte[bufferSize];

            while ((bytesRead = fs.Read(bytes, 0, bufferSize)) > 0)
            {
                fileStream.Write(bytes, 0, bytesRead);
            }
        }
    }

您可以使用Stream.CopyTo方法复制文件，如下所示：

public static string CopyFileStream(string outputDirectory, string inputFilePath)
{
    FileInfo inputFile = new FileInfo(inputFilePath);
    using (FileStream originalFileStream = inputFile.OpenRead())
    {
        var fileName = Path.GetFileName(inputFile.FullName);
        var outputFileName = Path.Combine(outputDirectory, fileName);
        using (FileStream outputFileStream = File.Create(outputFileName))
        {
            originalFileStream.CopyTo(outputFileStream);
        }
        return outputFileName;
    }
}

string fileName = "Mytest.txt";
    string sourcePath = @"C:\MyTestPath";
    string targetPath =  @"C:\MyTestTarget";
    string sourceFile = System.IO.Path.Combine(sourcePath, fileName);
    string destFile = System.IO.Path.Combine(targetPath, fileName);

    {
        System.IO.Directory.CreateDirectory(targetPath);
    }

    // To copy a file to another location and 
    // overwrite the destination file if it already exists.
    System.IO.File.Copy(sourceFile, destFile, true);