使用C#连接、操作MySQL数据库

Ecyun.com · 发表于 2019-7-7 22:39:45

sing System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.IO;
//Add MySql Library
using MySql.Data.MySqlClient;
namespace ConnectCsharpToMysql
{
class DBConnect
{
private MySqlConnection connection;
private string server;
private string database;
private string uid;
private string password;
//Constructor
public DBConnect()
{
Initialize();
}
//Initialize values
private void Initialize()
{
server = "localhost";
database = "csahrpdb";
uid = "root";
//password = "Abcd1234";
password = "123456";
string connectionString;
connectionString = "SERVER=" + server + ";" + "DATABASE=" + database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";
//server=127.0.0.1;user=root;database=testsql;port=3306;password=root;
connection = new MySqlConnection(connectionString);
}
//open connection to database
private bool OpenConnection()
{
try
{
connection.Open();
return true;
}
catch (MySqlException ex)
{
//When handling errors, you can your application's response based on the error number.
//The two most common error numbers when connecting are as follows:
//0: Cannot connect to server.
//1045: Invalid user name and/or password.
switch (ex.Number)
{
case 0:
MessageBox.Show("Cannot connect to server. Contact administrator");
break;
case 1045:
MessageBox.Show("Invalid username/password, please try again");
break;
}
return false;
}
}
//Close connection
private bool CloseConnection()
{
try
{
connection.Close();
return true;
}
catch (MySqlException ex)
{
MessageBox.Show(ex.Message);
return false;
}
}
//Insert statement
public void Insert()
{
string query = "INSERT INTO tableinfo (id,name, age) VALUES('11','John Smith', '33')";
//open connection
if (this.OpenConnection() == true)
{
//create command and assign the query and connection from the constructor
MySqlCommand cmd = new MySqlCommand(query, connection);
//Execute command
cmd.ExecuteNonQuery();
//close connection
this.CloseConnection();
}
}
//Update statement
public void Update()
{
string query = "UPDATE tableinfo SET id='22', name='Joe', age='22' WHERE name='John Smith'";
//Open connection
if (this.OpenConnection() == true)
{
//create mysql command
MySqlCommand cmd = new MySqlCommand();
//Assign the query using CommandText
cmd.CommandText = query;
//Assign the connection using Connection
cmd.Connection = connection;
//Execute query
cmd.ExecuteNonQuery();
//close connection
this.CloseConnection();
}
}
//Delete statement
public void Delete(int id)
{
string query = "DELETE FROM tableinfo WHERE id=" + id;
if (this.OpenConnection() == true)
{
MySqlCommand cmd = new MySqlCommand(query, connection);
cmd.ExecuteNonQuery();
this.CloseConnection();
}
}
//Select statement
public List<string>[] Select()
{
string query = "SELECT * FROM tableinfo";
//Create a list to store the result
List<string>[] list = new List<string>[3];
list[0] = new List<string>();
list[1] = new List<string>();
list[2] = new List<string>();
//Open connection
if (this.OpenConnection() == true)
{
//Create Command
MySqlCommand cmd = new MySqlCommand(query, connection);
//Create a data reader and Execute the command
MySqlDataReader dataReader = cmd.ExecuteReader();
//Read the data and store them in the list
while (dataReader.Read())
{
list[0].Add(dataReader["id"] + "");
list[1].Add(dataReader["name"] + "");
list[2].Add(dataReader["age"] + "");
}
//close Data Reader
dataReader.Close();
//close Connection
this.CloseConnection();
//return list to be displayed
return list;
}
else
{
return list;
}
}
//Count statement
public int Count()
{
string query = "SELECT Count(*) FROM tableinfo";
int Count = -1;
//Open Connection
if (this.OpenConnection() == true)
{
//Create Mysql Command
MySqlCommand cmd = new MySqlCommand(query, connection);
//ExecuteScalar will return one value
Count = int.Parse(cmd.ExecuteScalar()+"");
//close Connection
this.CloseConnection();
return Count;
}
else
{
return Count;
}
}
//Backup
public void Backup()
{
try
{
DateTime Time = DateTime.Now;
int year = Time.Year;
int month = Time.Month;
int day = Time.Day;
int hour = Time.Hour;
int minute = Time.Minute;
int second = Time.Second;
int millisecond = Time.Millisecond;
//Save file to C:\ with the current date as a filename
string path;
path = "C:\" + year + "-" + month + "-" + day + "-" + hour + "-" + minute + "-" + second + "-" + millisecond + ".sql";
StreamWriter file = new StreamWriter(path);
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = "mysqldump";
psi.RedirectStandardInput = false;
psi.RedirectStandardOutput = true;
psi.Arguments = string.Format(@"-u{0} -p{1} -h{2} {3}", uid, password, server, database);
psi.UseShellExecute = false;
Process process = Process.Start(psi);
string output;
output = process.StandardOutput.ReadToEnd();
file.WriteLine(output);
process.WaitForExit();
file.Close();
process.Close();
}
catch (IOException ex)
{
MessageBox.Show("Error , unable to backup!");
}
}
//Restore
public void Restore()
{
try
{
//Read file from C:\
string path;
path = "C:\\MySqlBackup.sql";
StreamReader file = new StreamReader(path);
string input = file.ReadToEnd();
file.Close();
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = "mysql";
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = false;
psi.Arguments = string.Format(@"-u{0} -p{1} -h{2} {3}", uid, password, server, database);
psi.UseShellExecute = false;
Process process = Process.Start(psi);
process.StandardInput.WriteLine(input);
process.StandardInput.Close();
process.WaitForExit();
process.Close();
}
catch (IOException ex)
{
MessageBox.Show("Error , unable to Restore!");
}
}
} }

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原文链接：https://www.cnblogs.com/xiebaochun/p/3329625.html

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提取码: zgct
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