[英]Executing a SQL query with C#
我想向我的數據庫添加一些信息。 我搜索了一些教程,但是都沒有用。
NonQuery可以執行他需要做的事情,因為消息框返回“成功”(1)。 但是它不會更新我的數據庫。 如果我將相同的查詢直接添加到“添加新查詢”到數據庫中,則它將起作用。
有人能幫我嗎?
我目前的班級代碼:
namespace BurnThatFat
{
class databaseconnection
{
//fields
SqlConnection connection;
string connectionstring;
public databaseconnection()
{
// fields waarde toewijzen
connectionstring = @"Data Source=(LocalDB)\MSSQLLocalDB;" +
@"AttachDbFilename=|DataDirectory|\Database2.mdf;Integrated Security=True";
connection = new SqlConnection(connectionstring);
OpenConnection();
CloseConnection();
}
public List<Object> getObjectsFromDatabase()
{
try
{
OpenConnection();
// sql query
// Datareader
// sqlcommand
// return list van objecten , objecten veranderd naar jouw wens van data.
CloseConnection();
}
catch (Exception)
{
throw;
}
return new List<object>();
}
private bool OpenConnection()
{
try
{
connection.Open();
return true;
}
catch (MySqlException ex)
{
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;
}
}
private bool CloseConnection()
{
try
{
connection.Close();
return true;
}
catch (MySqlException ex)
{
MessageBox.Show(ex.Message);
return false;
}
}
public void AddGebruiker()
{
string query = "insert into Gebruiker VALUES(3, 'Cihan', 'Kurt', 18, 'Man', 85, 75, 'Admin1', 'Test123', 'testen');";
using (connection)
{
SqlCommand command = new SqlCommand(query, connection);
OpenConnection();
int resultaat = command.ExecuteNonQuery();
if (resultaat == 1)
{
MessageBox.Show("succes");
}
else
{
MessageBox.Show("fail");
}
}
}
}
}
編輯:
這是我的按鈕等的代碼:
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;
// voor sql connectie.
using System.Data.SqlClient;
namespace BurnThatFat
{
public partial class SignUp : Form
{
databaseconnection db = new databaseconnection();
public SignUp()
{
InitializeComponent();
gb_login.Visible = false;
gb_Voornaam.Visible = false;
gb_Achternaam.Visible = false;
gb_leeftijdgeslacht.Visible = false;
gb_gewicht.Visible = false;
gb_email.Visible = false;
gb_Start.Visible = true;
}
private void btn_SignUp_Click(object sender, EventArgs e)
{
gb_Start.Visible = false;
gb_Voornaam.Visible = true;
}
private void btn_login_Click(object sender, EventArgs e)
{
gb_Start.Visible = false;
gb_login.Visible = true;
}
private void btn_loginvolgende_Click(object sender, EventArgs e)
{
gb_login.Visible = false;
// hier moet nog een GB!!!!!!
}
private void btn_voornaamvolgende_Click(object sender, EventArgs e)
{
gb_Voornaam.Visible = false;
gb_Achternaam.Visible = true;
}
private void btn_achternaamvolgende_Click(object sender, EventArgs e)
{
gb_Achternaam.Visible = false;
gb_leeftijdgeslacht.Visible = true;
}
private void btn_leeftijdvolgende_Click(object sender, EventArgs e)
{
gb_leeftijdgeslacht.Visible = false;
gb_gewicht.Visible = true;
}
// einde registratie
// opslaan van gegevens in database
private void btn_emailvolgende_Click(object sender, EventArgs e)
{
// gebruiker = new Gebruikerklasse();
// gebruiker.Naam = Convert.ToString(tb_voornaam.Text);
//// gebruiker.Achternaam = Convert.ToString(tb_achternaam.Text);
// gebruiker.Leeftijd = Convert.ToInt32(nud_leeftijd.Value);
/// gebruiker.Geslacht = Convert.ToString(cb_geslacht.Text);
// gebruiker.Huidig_gewicht = Convert.ToInt32(nud_huidiggewicht.Value);
// gebruiker.Streef_gewicht = Convert.ToInt32(nud_streefgewicht.Value);
/// gebruiker.Gebruikersnaam = Convert.ToString(tb_gebruikersnaam2.Text);
// gebruiker.Email = Convert.ToString(tb_email.Text);
// gebruiker.Wachtwoord = Convert.ToString(tb_wachtwoordsignup.Text);
db.AddGebruiker();
gb_email.Visible = false;
// hier moet nog een GB!!!!!
}
private void btn_gewichtvolgende_Click(object sender, EventArgs e)
{
gb_gewicht.Visible = false;
gb_email.Visible = true;
}
}
}
插入SQL Server數據庫的最簡單方法:
string connectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Database2.mdf;Integrated Security=True";
string commandText = "INSERT INTO MyTable (ID, Name, Address) VALUES (10, 'Bob', '123 Main Street');";
using (SqlConnection conn = new SqlConnection(connectionString))
using (SqlCommand cmd = new SqlCommand(commandText, conn))
{
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();
}
只要commandText
是一個有效的查詢,它應該插入一行。 最好為您的值使用參數,而不是像我在此處那樣對參數進行硬編碼-這樣可以避免SQL注入攻擊和其他潛在問題。 您可以在Google上搜索該內容(或您現在要問的問題),然后找到大量資源來幫助您。
如果您需要更多具體的幫助,請發布詳細信息,例如嘗試運行代碼時實際發生的情況-您是否會遇到異常?
在做其他事情之前,我會清理一堆東西。
首先,一起擺脫openconnection和closeconnection方法。 並且不要在您的類中保留連接的實例屬性。 使用using語句按需創建連接,因為在using語句的結尾,編譯器將在連接的IDisposable接口實現上插入對Dispose方法的調用,它將為您自動關閉連接。
因此,清理完所有不必要的代碼后,您在該類中真正應該擁有的就是Addgebrukier方法的實現,如下所示
public void AddGebruiker()
{
string query = "insert into Gebruiker VALUES(3, 'Cihan', 'Kurt', 18, 'Man', 85, 75, 'Admin1', 'Test123', 'testen');";
using (SqlConnection = new SqlConnection(connectionstring))
{
using (SqlCommand command = new SqlCommand(query, connection))
{
connection.Open();
int resultaat = command.ExecuteNonQuery();
if (resultaat == 1)
{
MessageBox.Show("succes");
}
else
{
MessageBox.Show("fail");
}
}
}
}
您還應該從app / web.config中的部分加載連接字符串,但是稍后可以在運行它之后執行此操作。
這是一個簡單的概念,應該對您來說非常合適。 只需更改ServerName,DatabaseName等。
using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;
namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
string connetionString = null;
SqlConnection connection ;
SqlDataAdapter adapter = new SqlDataAdapter();
string sql = null;
connetionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password";
connection = new SqlConnection(connetionString);
sql = "insert into product (Product_id,Product_name,Product_price) values(6,'Product6',600)";
try
{
connection.Open();
adapter.InsertCommand = new SqlCommand(sql, connection);
adapter.InsertCommand.ExecuteNonQuery();
MessageBox.Show ("Row inserted !! ");
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
}
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