C#中点击按钮 button7，读取SQL数据库中“业务订单总表”的“业务员”列，合并同类项后将值设为comboBox1的下拉项的所有C#代码

在C#中，要实现这个功能，首先需要连接到SQL数据库，然后查询数据、合并并填充ComboBox。以下是基本步骤的代码示例：

using System;
using System.Data.SqlClient;
using System.Collections.Generic;

// 假设已经添加了对System.Windows.Forms命名空间的引用

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

    private void button7_Click(object sender, EventArgs e)
    {
        // 连接到数据库（假设数据库名为MyDatabase，服务器地址、用户名和密码已设置）
        string connectionString = "Data Source=your_server_address;Initial Catalog=MyDatabase;User ID=your_username;Password=your_password";
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            try
            {
                connection.Open();

                // 查询业务订单总表中的"业务员"列（假设表名是BusinessOrders，字段名是Salesman）
                string query = "SELECT DISTINCT Salesman FROM BusinessOrders";
                SqlCommand command = new SqlCommand(query, connection);
                SqlDataReader reader = command.ExecuteReader();

                // 创建一个Dictionary用于存储并合并相同业务员的值
                Dictionary<string, int> salesmanCount = new Dictionary<string, int>();

                // 遍历查询结果，并更新字典
                while (reader.Read())
                {
                    string salesman = reader.GetString(0);
                    if (!salesmanCount.ContainsKey(salesman))
                        salesmanCount[salesman] = 1;
                    else
                        salesmanCount[salesman]++;
                }

                // 清空comboBox1
                comboBox1.Items.Clear();

                // 将合并后的数据添加到comboBox1
                foreach (KeyValuePair<string, int> entry in salesmanCount)
                {
                    comboBox1.Items.Add(entry.Key + ": " + entry.Value.ToString());
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error occurred: {ex.Message}");
            }
        }
    }
}