c# – 第 3 页 – Jeff Notes

C# 每两位插入一个空格

string txt = "12345678" ;
string result = Regex .Replace(txt, @"(\d{2}(?!$))", "$1 " );

每N位插入一个就把2改成N

上面只分操作全是数字的，如果是适应所有的，可以把\d换成.号

string txt = "ABCD1E2F4G" ;
string result = Regex .Replace(txt, @"(.{2}(?!$))", "$1 " );

ado.net 连接mysql的类

ado.net 连接mysql的类:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MySql.Data;
using MySql.Data.MySqlClient;

namespace VideoSpider
{
    public class DBConn
    {
#if DEBUG
        private static   string _connectionString = @"server=61.164.149.180;User ID=sql_zuqiu;Password=FULFQcvuFsqnbQSL;database=zuqiu_bak;";
#else
        private static string _connectionString = @"server=localhost;User=11xs;Password=HPU3aMJVzECQfVXR;database=11xs";
#endif
        public static MySqlConnection OpenConnection( string connstr = "" )
        {

            if (connstr != "" )
            {
                _connectionString = connstr;
            }
            var conn = new MySqlConnection(_connectionString);
            conn.Open();
            return conn;
        }
    }
}

C#非独占加载图片

Image _Image = Image .FromStream(new MemoryStream(System.IO.File .ReadAllBytes(Application.StartupPath + "\\v.jpg")));
pictureBox1.Image = _Image;

C#在线程中使用Invoke来调用UI线程里的控件

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace TextTool
{
    public partial class Form1 : Form
    {
        private Thread workThread = null; //工作线程
        private List <string> fileList = new List <string>();
        public Form1()
        {
            InitializeComponent();
        }

        // 导入 可多选
        private void button1_Click(object sender, EventArgs e)
        {
            Stream mystream;
            OpenFileDialog openfiledialog1 = new OpenFileDialog();
            openfiledialog1.Multiselect = true;//允许同时选择多个文件
            openfiledialog1.Filter = "txt files(*.txt)|*.txt|All files(*.*)|*.*" ;
            openfiledialog1.FilterIndex = 1;
            openfiledialog1.RestoreDirectory = true;
            if (openfiledialog1.ShowDialog() == DialogResult.OK)
            {
                if ((mystream = openfiledialog1.OpenFile()) != null)
                {
                    fileList.Clear();
                    for (int fi = 0; fi < openfiledialog1.FileNames.Length; fi++)
                    {
                        fileList.Add(openfiledialog1.FileNames[fi]);
                    }
                    mystream.Close();
                }

                listView1.Items.Clear();
                foreach (var filePath in fileList)
                {
                    ListViewItem lvi = new ListViewItem(filePath);
                    listView1.Items.Add(lvi);
                }
            }
        }

        // 合并处理并输出
        private void button2_Click(object sender, EventArgs e)
        {
            if (fileList.Count == 0)
            {
                MessageBox.Show("请先添加要处理的文件" );
                return;
            }

            SaveFileDialog savefiledialog1 = new SaveFileDialog();
            savefiledialog1.Filter = "txt files(*.txt)|*.txt" ;
            if (savefiledialog1.ShowDialog() == DialogResult.OK)
            {
                button2.Text = "处理中..." ;
                button2.Enabled = false;

                workThread = new Thread (WorkThread);
                workThread.Start(savefiledialog1.FileName);
            }
        }

        private int MyCompareString(string x, string y)
        {
            int pos1 = x.IndexOf("(" );
            int pos2 = x.IndexOf(")" );
            int cnt1 = Convert .ToInt32(x.Substring(pos1 + 1, pos2-pos1 -1));

            pos1 = y.IndexOf( "(");
            pos2 = y.IndexOf( ")");
            int cnt2 = Convert .ToInt32(y.Substring(pos1 + 1, pos2 - pos1 - 1));
 
            if (cnt1 > cnt2)
            {
                return -1;
            }
            else if (cnt1< cnt2)
            {
                return 1;
            }
            else
            {
                return 0;
            }
        }

        public void WorkThread(object savePath)
        {
            List<string > allLines = new List< string>();
            foreach (var filePath in fileList)
            {
                allLines.AddRange( File.ReadAllLines(filePath));
            }

            int totalCount = 0;
            List<string > outputList = new List< string>();
            foreach (var line in (from t in allLines where t.Trim() != "" select t).Distinct())
            {
                int count = (from c in allLines where c == line select c).Count();
                totalCount += count;
                outputList.Add( $"{line} ( {count})");
            }
            outputList.Sort(MyCompareString);
            outputList.Add( $"总数：{totalCount}" );
            File.WriteAllLines(savePath.ToString(), outputList);

            Invoke( new MethodInvoker (delegate ()
            {
                button2.Text = "合并处理输出" ;
                button2.Enabled = true;
                MessageBox.Show("处理完成！" );
            }));
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (workThread != null && workThread.IsAlive)
            {
                workThread.Abort();
            }
        }
    }
}

如果是WPF程序，则在线程中像下面这样操作控件

this.Dispatcher.Invoke(new Action( delegate
{
    lblState.Content = "正在检测域名" + fullUrl;
}));

C#使用OleDB连接Access数据库

C#使用OleDB连接Access数据库的代码：

public class DbHelper
{
    static DbHelper()
    {
        connectionString = GetConnectionString();
    }

    private static string connectionString;

    private static string GetConnectionString()
    {
        return string.Format( "File Name={0}\\link.udl", Application .StartupPath);
    }


    public static DataTable ExecuteDataTable( string sql)
    {
        try
        {
            using ( OleDbDataAdapter da = new OleDbDataAdapter (sql, connectionString))
            {
                DataSet ds = new DataSet();
                da.Fill(ds);
                return ds.Tables[0];
            }
        }
        catch( Exception e)
        {
            MessageBox.Show(e.Message);
            return null;
        }

    }

    public static void ExecuteNonQuery( string sql)
    {
        using ( OleDbConnection conn = new OleDbConnection (connectionString))
        {
            try
            {
                conn.Open();

                OleDbCommand cmd = conn.CreateCommand();
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = sql;
                cmd.ExecuteNonQuery();
                cmd.Dispose();
            }
            finally
            {
                if (conn.State == ConnectionState.Open) conn.Close();
            }
        }          
    }

}

C#判断一个类型是否是集合类型

C#判断一个类型是否是集合类型：

typeof(T).GetTypeInfo().ImplementedInterfaces.Contains(typeof(IEnumerable))

C# 遍历文件下所有文件

string[] files = Directory .GetFiles(Application.StartupPath, "*.mdb", SearchOption .AllDirectories);

如果要遍历所有的，把 *.mdb 改成*即可。

C#二维数组的定义

string[,] items = new string[_totalCount, 32];

和string[][] = new string[32][]; 是有区别的。

C#读取十六进制文件

BinaryReader br = new BinaryReader( File.OpenRead(_fileName));
br.BaseStream.Position = 0xF; 
string first_player = br.ReadByte().ToString("X2"); //ToString("X2") 为C#中的字符串格式控制符。X表示十六进制，2为每次都是两位数
br.Close();
MessageBox.Show(first_player);

C#使用Uri.EscapeDataString对URL参数进行编码

System.Web.HttpUtility.UrlEncode

都是对参数进行编码，要像下面这样写：

string data = string.Format(@"{{""ptwebqq"":""{0}"",""clientid"":{1},""psessionid"":""{2}"",""status"":""online""}}", _PTWebQQ, ClientID, PSessionID);
data = "r=" + Uri.EscapeDataString(data);

而不要把r=也编码进去！！！

血的教训，一晚上加一上午都浪费在这上面了！！！！

而python的urllib.parse.urlencode传入的是字典，所以避免了这个坑。