前言:
本文以连接SQLite为例进行代码演示
一、首先建立里一个模型类
public class MyData { public int id { get; set; } public string name { get; set; } public int age { get; set; } public string sex { get; set; } public string address { get; set; } }
二、封装一个连接SQLite方法,并返回BindingList集合用于DataGridView使用
private static readonly object _lock = new object();//确保线程安全 public static BindingList<MyData> GetData(string sql, int offset, int limit) { lock (_lock) { // 创建一个BindingList来保存查询结果 BindingList<MyData> dataList = new BindingList<MyData>(); // 使用SQLiteConnection打开数据库连接 using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { connection.Open(); using (SQLiteCommand command = new SQLiteCommand(sql, connection)) { // 添加分页的查询语句 command.CommandText = sql + " LIMIT @limit OFFSET @offset"; command.Parameters.AddWithValue("@limit", limit); command.Parameters.AddWithValue("@offset", offset); using (SQLiteDataReader reader = command.ExecuteReader()) { while (reader.Read()) { // 读取数据库中的每一行数据,并将其添加到BindingList MyData data = new MyData { id = reader.GetInt32(0), name = reader.IsDBNull(1) ? "N/A" : reader.GetString(1), age = reader.IsDBNull(2) ? 0 : reader.GetInt32(2), sex = reader.IsDBNull(3) ? "N/A" : reader.GetString(3), address = reader.IsDBNull(4) ? "N/A" : reader.GetString(4) }; dataList.Add(data); } } } } return dataList; } }
三、数据展示(查、改,删、增)
public static void BindDataGridView(DataGridView dataGridView) { // 计算偏移量,偏移量 = (当前页 - 1) * 每页条数 int offset = (currentPage - 1) * pageSize; // SQL查询语句 string sql = "SELECT * FROM ceshi Where Status!='-1'"; // 获取数据并绑定到DataGridView BindingList<MyData> dataList = GetData(sql, offset, pageSize); }
public static void SQLUPDATE(MyData data, string sql, DataGridView dataGridView) { var bindingList = dataGridView.DataSource as BindingList<MyData>; if (bindingList != null) { // 找到要修改的项 var dataToEdit = bindingList.FirstOrDefault(d => d.id == data.id); if (dataToEdit != null) { // 更新BindingList中的数据 dataToEdit.name = data.name; dataToEdit.age = data.age; dataToEdit.sex = data.sex; dataToEdit.address = data.address; using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { connection.Open(); // 创建SQLite命令对象 using (SQLiteCommand command = new SQLiteCommand(sql, connection)) { // 执行更新操作 command.ExecuteNonQuery(); } } dataGridView.Refresh(); } } }
public static void SQLDelete(int id, DataGridView dataGridView) { var bindingList = dataGridView.DataSource as BindingList<MyData>; if (bindingList != null) { var itemToDelete = bindingList.FirstOrDefault(d => d.id == id); if (itemToDelete != null) { bindingList.Remove(itemToDelete); // 从BindingList中移除 using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { connection.Open(); // 删除SQL语句 string sql = "UPDATE ceshi set Status='-1' WHERE id = @id"; // 创建SQLite命令对象 using (SQLiteCommand command = new SQLiteCommand(sql, connection)) { // 添加参数 command.Parameters.AddWithValue("@id", id); // 执行删除操作 command.ExecuteNonQuery(); } } BindDataGridView(dataGridView); } } }
public static void SQLAdd(MyData data, string sql, DataGridView dataGridView) { // 将新数据项添加到BindingList中 var bindingList = dataGridView.DataSource as BindingList<MyData>; if (bindingList != null) { bindingList.Add(data); // 添加新数据 } using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { connection.Open(); // 创建SQLite命令对象 using (SQLiteCommand command = new SQLiteCommand(sql, connection)) { // 执行插入操作 command.ExecuteNonQuery(); // 获取插入数据的自增ID long newId = connection.LastInsertRowId; data.id = (int)newId; // 返回自增的ID } BindDataGridView(dataGridView); } }
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