尝试连接到远程地址数据库时发生超时错误

Question

我不断收到超时错误，只有几次我的代码工作。我正在阅读这个论坛，我不得不在mysql之前使用“使用”。所以我尝试添加它，但仍然没有运气。也许我用它错了？离开了我的数据库最后一个连接没有“使用”，所以你们可以看到它是在第一次

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Forms; 
using MySql.Data.MySqlClient; 

namespace WindowsFormsApplication4 
{ 
    public partial class Form3 : Form 
    { 
     public Form3() 
     { 
      InitializeComponent(); 
      FillCombo(); 
     } 
     void FillCombo() 
     { 
      string dbcon = "SERVER=IP;DATABASE=mudiw_test;UID=mudiw_test;PASSWORD=PASS"; 
      string Query = "select * from mudiw_test.Registration ;"; 
      using (MySqlConnection conDatabase = new MySqlConnection(dbcon)) 
      { 
       using (MySqlCommand cmDatabase = new MySqlCommand(Query, conDatabase)) 
       { 
        MySqlDataReader myReader; 
        try 
        { 
         conDatabase.Open(); 
         myReader = cmDatabase.ExecuteReader(); 
         while (myReader.Read()) 
         { 
          string sName = myReader.GetString("Name"); 
          comboBox1.Items.Add(sName); 
         } 
        } 
        catch (Exception ex) 
        { 
         MessageBox.Show(ex.Message); 
        } 
       } 
      } 
     } 

     private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      string dbcon = "SERVER=IP;DATABASE=mudiw_test;UID=mudiw_test;PASSWORD=PASS"; 
      string Query = "select * from mudiw_test.Registration where Name='" + comboBox1.Text + "' ;"; 
      using (MySqlConnection conDatabase = new MySqlConnection(dbcon)) 
      { 
       using (MySqlCommand cmDatabase = new MySqlCommand(Query, conDatabase)) 
       { 
        MySqlDataReader myReader; 
        try 
        { 
         conDatabase.Open(); 
         myReader = cmDatabase.ExecuteReader(); 
         while (myReader.Read()) 
         { 
          string sName = myReader.GetString("Name"); 
          string sId = myReader.GetString("ID"); 
          string sEmail = myReader.GetString("Email"); 
          string sAddress = myReader.GetString("Address"); 
          string sPhone = myReader.GetString("Phone"); 
          string sVisits = myReader.GetString("Visits"); 
          name.Text = sName; 
          id.Text = sId; 
          email.Text = sEmail; 
          address.Text = sAddress; 
          phone.Text = sPhone; 
          address.Text = sAddress; 
          visits.Text = sVisits; 
         } 
        } 
        catch (Exception ex) 
        { 
         MessageBox.Show(ex.Message); 
        } 
       } 
      } 
     } 

     private void comboBox2_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      if (comboBox2.SelectedItem == "Mantenimiento") 
      { 
       int value; 
       if (Int32.TryParse(visits.Text, out value)) 
       { 
        if (value < 3) 
        { 
         price.Text = "150"; 
         total.Text = "150"; 
         discount.Text = "0%"; 
        } 
        else if (value >= 3 && value <= 6) 
        { 
         price.Text = "150"; 
         total.Text = "127.50"; 
         discount.Text = "15%"; 
        } 
        else if (value >= 7) 
        { 
         price.Text = "150"; 
         total.Text = "112.50"; 
         discount.Text = "25%"; 
        } 
       } 
      } 
     } 

     private void tabPage1_Click(object sender, EventArgs e) 
     { 

     } 

     private void button1_Click(object sender, EventArgs e) 
     { 
      string dbcon = "SERVER=IP;DATABASE=mudiw_test;UID=mudiw_test;PASSWORD=PASS"; 
      string Query = "insert into mudiw_test.Registration (Name,ID,Email,Address,Phone) values('" + this.name.Text + "','" + this.id.Text + "','" + this.email.Text + "','" + this.address.Text + "','" + this.phone.Text + "');"; 
      MySqlConnection conDatabase = new MySqlConnection(dbcon); 
      MySqlCommand cmDatabase = new MySqlCommand(Query, conDatabase); 
      MySqlDataReader myReader; 
      try 
      { 
       conDatabase.Open(); 
       myReader = cmDatabase.ExecuteReader(); 
       MessageBox.Show("Saved"); 
       while (myReader.Read()) 
       { 

       } 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
     } 
    } 
} 

Answer 1

超时将不相关的using声明;将连接包装在using中只需确保在完成连接时处理连接。超时可能意味着您的计算机和数据库之间存在网络连接问题，或者您提供了错误的服务器名称。