c#如何在运行update查询后保留列表中的旧值

string connectionString = "YourConnectionString";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    
    string updateQuery = "UPDATE YourTable SET Column1 = @NewValue WHERE Column2 = @Condition";
    using (SqlCommand command = new SqlCommand(updateQuery, connection))
    {
        // 设置参数
        command.Parameters.AddWithValue("@NewValue", newValue);
        command.Parameters.AddWithValue("@Condition", condition);
        
        // 执行更新查询
        command.ExecuteNonQuery();
    }
}

List<string> oldValues = new List<string>();

// 查询旧值
string selectQuery = "SELECT Column1 FROM YourTable WHERE Column2 = @Condition";
using (SqlCommand command = new SqlCommand(selectQuery, connection))
{
    command.Parameters.AddWithValue("@Condition", condition);
    
    using (SqlDataReader reader = command.ExecuteReader())
    {
        while (reader.Read())
        {
            string oldValue = reader.GetString(0);
            oldValues.Add(oldValue);
        }
    }
}