Question

我在c＃中创建一个windows表单，其中checkedlistbox中的所有值都将存储到数据库中。但是代码确实有效：

仅检查的最后一个值是在数据库上重复存储，就像下面的数据一样

famhistory

员工ID（id）不会显示为外键，但它会显示在表name上，就像下面的数据一样

表：famhistory

famid           famcon          id
30              stroke
31              stroke
32              stroke

表：name

eid             name
2010-0244       Jam Lagcao

有人可以帮我解决问题吗？非常感谢你的帮助。

以下是我在c＃中的代码：

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 Npgsql;

namespace WindowsFormsApplication1
{
    public partial class Form6 : Form
    {
        public Form6()
        {
            InitializeComponent();
            this.Load += Form6_Load;
            button1.Click += button1_Click;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            NpgsqlConnection conn = new NpgsqlConnection("Server=localhost;Port=5432;User Id=postgres;Password=021393;Database=postgres;");
            NpgsqlCommand cmd = new NpgsqlCommand("Insert into name(eid, name) Values (@eid, @name)", conn);
            cmd.Parameters.AddWithValue("@eid", textBox1.Text);
            cmd.Parameters.AddWithValue("@name", textBox2.Text);
            conn.Open();

            foreach (DataRowView view in checkedListBox1.CheckedItems)
            {
                NpgsqlCommand cmd2 = new NpgsqlCommand("Insert into famhistory (famcon) Values (@famcon)", conn);
                string value = view.Row[0].ToString();
                Console.WriteLine(view[checkedListBox1.ValueMember].ToString());  
                cmd2.Parameters.AddWithValue("@famcon", checkedListBox1.SelectedValue);
                cmd2.ExecuteNonQuery();  
            }

            cmd.ExecuteNonQuery();
            MessageBox.Show("Data has been saved");
            conn.Close();
        }

        private void Form6_Load(object sender, EventArgs e)
        {
            DataSet ds = new DataSet();
            DataTable dt = new DataTable();

            string connstring = ("Server=localhost;Port=5432;User Id=postgres;Password=021393;Database=postgres;");
            NpgsqlConnection conn = new NpgsqlConnection(connstring);
            NpgsqlCommand cmd = new NpgsqlCommand("SELECT * FROM condition", conn);
            cmd.CommandType = CommandType.Text;
            conn.Open();
            NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
            dt.TableName = "condition";
            da.Fill(dt);
            checkedListBox1.DataSource = dt;
            checkedListBox1.DisplayMember = "conname";
            checkedListBox1.ValueMember = "conname";
            checkedListBox1.BindingContext = new BindingContext();
            string[] condition = dt.Rows[0]["conname"].ToString().Split(',');

        }
    }
}

Answer 1

将插入操作代码更改为famhistory表，如下所示

foreach (var item in checkedListBox1.CheckedItems)
{
  NpgsqlCommand cmd2 = new NpgsqlCommand("Insert into famhistory (famcon) Values (@famcon)", conn);
cmd2.Parameters.AddWithValue("@famcon", item.ToString());
cmd2.ExecuteNonQuery();  
}

不确定您在DataRowView view声明中使用foreach的原因;那是错的。

此外，请参阅我使用的是item.ToString()而不是checkedListBox1.SelectedValue，它只会为您提供最后一个选定的值。

将所有选中的值从checkedlistbox存储到数据库

1 个答案: