C＃将数据插入数据库Windows窗体应用程序

Question

I need to build a application where people can make a reservation but before doing that they need to fill in some information. I get this error code at the moment when i try to save the data: An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll

This is my code:

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

namespace BonTemps
{
    public partial class Home : Form
    {
        public Home()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var Form1 = new Form1();
            Form1.Show();
        }

        private void tabPage1_Click(object sender, EventArgs e)
        {

        }

        private void label2_Click(object sender, EventArgs e)
        {

        }

        private void Home_Load(object sender, EventArgs e)
        {
            // TODO: This line of code loads data into the 'bonTempsDBDataSet.Tafel' table. You can move, or remove it, as needed.
            this.tafelTableAdapter.Fill(this.bonTempsDBDataSet.Tafel);

        }

        private void btnOpslaan_Click(object sender, EventArgs e)
        {
            SqlConnection sc = new SqlConnection();
            SqlCommand com = new SqlCommand();
            sc.ConnectionString = ("Data Source=ACER;Initial Catalog=BonTempsDB;Integrated Security=True");
            sc.Open();

            com.Connection = sc;
            com.CommandText = (@"INSERT INTO Klant (Naam, Adres, Woonplaats, Telefoonnummer, EmailAdres), VALUES ('" + txtNaam.Text + "','" + txtAdres.Text + "','" + txtWoon.Text + "','" + txtTel.Text + "','" + txtMail.Text + "'");
            com.ExecuteNonQuery();

            sc.Close();

        }

    }
}

Answer 1

Remove the comma Before VALUES.

If that is not enough, you can debug and copy the generated string from Command Text and try running it directly in SQL Server Mangement Studio or similar

Answer 2

出现印刷错误，请删除“值”一词前的“逗号”。

Answer 3

You have to pass an open SqlConnection to your SqlCommand to make it work:

com.Connection = sc;

Also, consider using named parameters to pass data to your query to make your query more error-proof:

SqlConnection sc = new SqlConnection();
SqlCommand com = new SqlCommand();
sc.ConnectionString = ("Data Source=ACER;Initial Catalog=BonTempsDB;Integrated Security=True");
sc.Open();

com.Connection = sc;
com.CommandText = @"INSERT INTO Klant (Naam, Adres, Woonplaats, Telefoonnummer, EmailAdres) VALUES (@naam, @adres, @woon, @tel, @mail)";
com.Parameters.AddWithValue("@naam", txtNaam.Text);
com.Parameters.AddWithValue("@adres", txtAdres.Text);
com.Parameters.AddWithValue("@woon", txtWoon.Text);
com.Parameters.AddWithValue("@tel", txtTel.Text);
com.Parameters.AddWithValue("@mail", txtMail.Text);

com.ExecuteNonQuery();
sc.Close();

Answer 4

using (var sc = new SqlConnection("Data Source=ACER;Initial Catalog=BonTempsDB;Integrated Security=True"))
{
    using (var com = new SqlCommand("sql cmd text", sc))
    {
        try
        {
            sc.Open();
            com.ExecuteNonQuery();
        }
        catch
        {

        }
    }
}