c# .net 把一个文件夹下的文件复制到另一个文件夹下

///<summary>  
        ///c# .net 创建文件夹  
        ///</summary>  
        ///<param name="targetDir"></param>  
        public static void CreateDirectory(string targetDir)  
        {  
            DirectoryInfo dir = new DirectoryInfo(targetDir);  
            if (!dir.Exists)  
                dir.Create();  
        }  

///<summary>  
        ///复制指定目录的所有文件  
        ///</summary>  
        ///<param name="sourceDir">原始目录</param>  
        ///<param name="targetDir">目标目录</param>  
        ///<param name="overWrite">如果为true,覆盖同名文件,否则不覆盖</param>  
        ///<param name="copySubDir">如果为true,包含目录,否则不包含</param>  
        public static void CopyFiles(string sourceDir, string targetDir, bool overWrite, bool copySubDir)  
        {  
            //复制当前目录文件  
            foreach (string sourceFileName in Directory.GetFiles(sourceDir))  
            {  
                string targetFileName = Path.Combine(targetDir, sourceFileName.Substring(sourceFileName.LastIndexOf("\\") + 1));  
                if (File.Exists(targetFileName))  
                {  
                    if (overWrite == true)  
                    {  
                        File.SetAttributes(targetFileName, FileAttributes.Normal);  
                        File.Copy(sourceFileName, targetFileName, overWrite);  
                    }  
                }  
                else 
                {  
                    File.Copy(sourceFileName, targetFileName, overWrite);  
                }  
            }  
            //复制子目录  
            if (copySubDir)  
            {  
                foreach (string sourceSubDir in Directory.GetDirectories(sourceDir))  
                {  
                    string targetSubDir = Path.Combine(targetDir, sourceSubDir.Substring(sourceSubDir.LastIndexOf("\\") + 1));  
                    if (!Directory.Exists(targetSubDir))  
                        Directory.CreateDirectory(targetSubDir);  
                    CopyFiles(sourceSubDir, targetSubDir, overWrite, true);  
                }  
            }  
        }  
    }