private static void CreateSimpleFile() {
string fileName = ".\\test.txt";
string destFileName = "c:\\test1.txt";
File.CreateText(fileName);                      //创建新的文件;

if (!File.Exists(destFileName))                 //判断文件是否存在
            {
File.Copy(fileName, destFileName, false);   //拷贝文件
            }
else {
File.Delete(destFileName);                  //如果已经存在了,则先删除已有文件,再拷贝.
                File.Copy(fileName,destFileName,false);
}
}

private static void CreateComplexFile() {
//创建文件,写入内容;
            string fileName = ".\\complexFile.txt";
StreamWriter writer = new StreamWriter(fileName, false, System.Text.Encoding.GetEncoding("GB2312"));
writer.WriteLine("Hello StreamWriter!");
if (writer.Encoding == System.Text.Encoding.GetEncoding("GB2312"))
{
writer.WriteLine("swriter.Encoding is GB2312");
}
writer.Flush();
writer.Close();
//读入文件内容.
            StreamReader reader = new StreamReader(fileName,System.Text.Encoding.GetEncoding("GB2312"),false,1024);
string line = reader.ReadLine();
Console.WriteLine(line);
line = reader.ReadLine();
Console.WriteLine(line);
reader.Close();
}