c#写一个数据库连接封装

以下是一个简单的数据库连接封装的示例代码，使用了C#中的ADO.NET：

using System;
using System.Data;
using System.Data.SqlClient;

namespace DatabaseConnection
{
    public class DatabaseConnector
    {
        private string connectionString;
        private SqlConnection connection;

        public DatabaseConnector(string connectionString)
        {
            this.connectionString = connectionString;
            this.connection = new SqlConnection(connectionString);
        }

        public void OpenConnection()
        {
            if (connection.State != ConnectionState.Open)
            {
                connection.Open();
            }
        }

        public void CloseConnection()
        {
            if (connection.State != ConnectionState.Closed)
            {
                connection.Close();
            }
        }

        public DataTable ExecuteQuery(string query)
        {
            DataTable dataTable = new DataTable();

            try
            {
                OpenConnection();

                SqlCommand command = new SqlCommand(query, connection);
                SqlDataAdapter adapter = new SqlDataAdapter(command);
                adapter.Fill(dataTable);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                CloseConnection();
            }

            return dataTable;
        }

        public void ExecuteNonQuery(string query)
        {
            try
            {
                OpenConnection();

                SqlCommand command = new SqlCommand(query, connection);
                command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                CloseConnection();
            }
        }
    }
}

使用方法：

string connectionString = "Data Source=.;Initial Catalog=MyDatabase;Integrated Security=True";
DatabaseConnector connector = new DatabaseConnector(connectionString);

// 查询
string query = "SELECT * FROM MyTable";
DataTable dataTable = connector.ExecuteQuery(query);

foreach (DataRow row in dataTable.Rows)
{
    Console.WriteLine(row["ColumnName"]);
}

// 非查询操作
string insertQuery = "INSERT INTO MyTable (ColumnName) VALUES ('Value')";
connector.ExecuteNonQuery(insertQuery);