這個是第一個介面的程式碼：

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;
using System.Data.SqlClient;

namespace 登入x
{
    public partial class Form1 : Form
    {
        public
 
 Form1()
        {
            InitializeComponent();
        }

        private void userInfoBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            this.Validate();
            this.userInfoBindingSource.EndEdit();
            this.tableAdapterManager.UpdateAll(this.studentRecordDataSet);

        }

        private
 
 void Form1_Load(object sender, EventArgs e)
        {
            // TODO: 這行程式碼將資料載入到表“studentRecordDataSet1.UserInfo”中。您可以根據需要移動或刪除它。
            this.userInfoTableAdapter1.Fill(this.studentRecordDataSet1.UserInfo);
            // TODO: 這行程式碼將資料載入到表“studentRecordDataSet.UserInfo”中。您可以根據需要移動或刪除它。
            this
 
.userInfoTableAdapter.Fill(this.studentRecordDataSet.UserInfo);

        }

        private void passwordLabel_Click(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            string connString = @"Data Source=.;Initial Catalog=studentrecord;Integrated Security=True";
            SqlConnection conn = new SqlConnection(connString);
            string sql = "select count(*) from UserInfo where username='" + userNameComboBox.Text + "'and password='" + passwordTextBox.Text + "'";
            conn.Open();
            SqlCommand comm = new SqlCommand(sql, conn);
            int num = (int)comm.ExecuteScalar();
            if (num > 0)
            {
                Form2 frm2 = new Form2();
                frm2.Show();

            }
            else
            {
                MessageBox.Show("對不起，使用者名稱和密碼並不匹配！", "登陸失敗");
            }
            conn.Close();
        }

        private void userNameComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

        private void passwordTextBox_TextChanged(object sender, EventArgs e)
        {

        }
    }
}

這個是第二個介面的程式碼：

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;

namespace 登入x
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void label1_Click(object sender, EventArgs e)
        {

        }
    }
}

執行結果如圖：

很簡陋的一個登入介面，後期還有升級版的哦！