csharp

DataBase butt joint:
if(DataBase.Exists)
{
come on!
Attention :localhost、port、DataBasename 、username、password
picture path
}
if(!DataBase.Exists)
{
first: to find DataBase server exists visual tool connection DB( find username password through xml)
second: butt joint
}
if(!table.fields.Exists)
{
find view select * from viewname
}
DataBaseResotre：SQL Server Restore：
mdf文件 附加进行还原
将mdf文件以及log.mdf日志文件全部拷贝到SQL Server数据库的安装目录下
的DATA文件夹下，然后进行找到该目录 找到mdf文件 进行还原

Download files from ftp:
WebClient wc = new WebClient();
wc.Headers.add("User_Agent","Chrome");
wc.credentials = new NetworkCredential("username", "password");
wc.DownloadFile("ftp://10.4.8.202:26/download.txt","c://download1.txt");

Download picture from Internet:
Core code:(WebClient function is visit url)
WebClient wc = new WebClient();
wc.Headers.add("User_Agent","Chrome");
wc.downloadFile("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1521534886900&di=80d30358851dd53dcebb152fc76291ca&imgtype=0&src=http%3A%2F%2Fupload.news.cecb2b.com%2F2016%2F0327%2F1459067610166.jpg", @"D:\ftp\image3.gif");

IoStreamFile/Folder:
Folder:
string path = @"c:\MyDir";
Directory.CreateDirectory(path);
File(create file and write):
string path = @"c:\MyDir\file1.txt";
FileStream fr = new FileSteam(path,FileMode.CreateNew);
StreamWrite sw = new StreamWrite(fr);
sw.write("This is write to path");
File(read):
string line ;
StringReader sr = new StringReader(path);
while(line = sr.Reader() != null)
{
Console.WriterLine(line.toString()); }

Csharp中解决生成多个随机数重复问题：
int randnew = new Random(Guid.NewGuid().GetHashCode()).Next(0, 10);