萌新求助，刚学了不久，写了点代码，点查询按钮没反应，求大佬看

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.OleDb;
namespace 管理
{
public partial class Form1 : Form
{
private OleDbConnection connection;
private string connectionString;
public Form1()
{
InitializeComponent();
InitializeDatabaseConnection();
PopulateComboBoxes();
connection.Close();
}
private void InitializeDatabaseConnection()
{
connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Users\\Administrator\\Desktop\\Database.mdb;Persist Security Info=False;";
connection = new OleDbConnection(connectionString);
try
{
connection.Open();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
connection = null;
}
}
private void PopulateComboBoxes()
{
// 填充队长（队长名称）到 comboBox1
string query = "SELECT 队长名称 FROM 队长";
using (OleDbCommand command = new OleDbCommand(query, connection))
{
using (OleDbDataReader reader = command.ExecuteReader())
{
List<string> names = new List<string>();
while (reader.Read())
{
names.Add(reader["队长名称"].ToString());
}
comboBox1.DataSource = names;
comboBox1.DisplayMember = "队长名称";
}
}
// 填充工程（工程类型）到 comboBox3
query = "SELECT 工程类型 FROM 工程";
using (OleDbCommand command = new OleDbCommand(query, connection))
{
using (OleDbDataReader reader = command.ExecuteReader())
{
List<string> names = new List<string>();
while (reader.Read())
{
names.Add(reader["工程类型"].ToString());
}
comboBox3.DataSource = names;
comboBox3.DisplayMember = "工程类型";
}
}
// 填充区域（区域）到 comboBox2
query = "SELECT 区域 FROM 区域";
using (OleDbCommand command = new OleDbCommand(query, connection))
{
using (OleDbDataReader reader = command.ExecuteReader())
{
List<string> names = new List<string>();
while (reader.Read())
{
names.Add(reader["区域"].ToString());
}
comboBox2.DataSource = names;
comboBox2.DisplayMember = "区域";
}
}
// 填充用户（名称）到 comboBox4
query = "SELECT 名称 FROM 用户表";
using (OleDbCommand command = new OleDbCommand(query, connection))
{
using (OleDbDataReader reader = command.ExecuteReader())
{
List<string> names = new List<string>();
while (reader.Read())
{
names.Add(reader["名称"].ToString());
}
comboBox4.DataSource = names;
comboBox4.DisplayMember = "名称";
}
}
}
private void CloseDatabaseConnection()
{
if (connection != null && connection.State == ConnectionState.Open)
{
connection.Close();
connection = null;
}
}
private void Button1_Click(object sender, EventArgs e)
{
MessageBox.Show("没做好");
}
private void Button3_Click(object sender, EventArgs e)
{
string query = "SELECT * FROM 图纸信息 WHERE 1=1";
using (OleDbCommand cmd = new OleDbCommand(query, connection))
{
try
{
// 根据文本框和下拉框的输入构建查询条件
if (!string.IsNullOrEmpty(textBox1.Text))
{
query += " AND 图纸名称 = @图纸名称";
}
if (!string.IsNullOrEmpty(comboBox3.Text))
{
query += " AND 类型 = @类型";
}
if (!string.IsNullOrEmpty(comboBox2.Text))
{
query += " AND 区域 = @区域";
}
if (!string.IsNullOrEmpty(comboBox1.Text))
{
query += " AND 队长 = @队长";
}
// ... 可以继续为其他文本框和下拉框添加条件 ...
cmd.Parameters.AddWithValue("@图纸名称", textBox1.Text);
cmd.Parameters.AddWithValue("@类型", comboBox3.Text);
cmd.Parameters.AddWithValue("@区域", comboBox2.Text);
cmd.Parameters.AddWithValue("@队长", comboBox1.Text);
// ... 为其他参数添加值 ...
connection.Open();
OleDbDataReader reader = cmd.ExecuteReader();
dataGridView1.DataSource = reader; // 将查询结果绑定到DataGridView
reader.Close();
connection.Close();
}
catch (Exception ex)
{
// 处理异常，例如显示错误消息或记录错误日志
MessageBox.Show("查询过程中出现错误: " + ex.Message);
}
}
}
}
}