C#使用OleDb操作Excel和数据库的策略

string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\\path\\to\\file.xlsx;Extended Properties='Excel 12.0 Xml;HDR=YES;'";
using(OleDbConnection conn = new OleDbConnection(connectionString))
{
    conn.Open();
    OleDbCommand cmd = new OleDbCommand("SELECT * FROM [Sheet1$]", conn);
    OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
    DataSet ds = new DataSet();
    adapter.Fill(ds);
    DataTable data = ds.Tables[0];
    // 数据现在存储在data中，可以进行进一步处理
}

using (OleDbConnection conn = new OleDbConnection(connectionString))
{
    conn.Open();  // 打开连接

    // 构建插入命令
    OleDbCommand cmd = new OleDbCommand("INSERT INTO [Sheet1$] (Column1, Column2) VALUES ('Value1', 'Value2')", conn);

    // 执行插入命令
    cmd.ExecuteNonQuery();

    // 关闭连接
    conn.Close();
}

DataTable dt = new DataTable();
// 假设dt已经被填充了数据
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
    OleDbDataAdapter adapter = new OleDbDataAdapter();
    adapter.InsertCommand = new OleDbCommand("INSERT INTO [Sheet1$] (Column1, Column2) VALUES (?, ?)", conn);
    adapter.InsertCommand.Parameters.Add("@Column1", OleDbType.VarChar, 255, "Column1");
    adapter.InsertCommand.Parameters.Add("@Column2", OleDbType.VarChar, 255, "Column2");

    conn.Open();
    adapter.Update(dt);  // 更新Excel文件
    conn.Close();
}

using System;
using System.Data;
using System.Data.OleDb;

class Program
{
    static void Main()
    {
        string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\yourdatabase.mdb;";

        // 创建一个新的OleDbConnection，并将其封装在using语句中以确保资源的释放
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            connection.Open();

            // 创建（Create）
            using (OleDbCommand command = new OleDbCommand("INSERT INTO Employees (FirstName, LastName) VALUES ('John', 'Doe')", connection))
            {
                command.ExecuteNonQuery();
            }

            // 读取（Read）
            using (OleDbCommand command = new OleDbCommand("SELECT FirstName, LastName FROM Employees", connection))
            using (OleDbDataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    Console.WriteLine($"{reader["FirstName"]} {reader["LastName"]}");
                }
            }

            // 更新（Update）
            using (OleDbCommand command = new OleDbCommand("UPDATE Employees SET LastName = 'Smith' WHERE FirstName = 'John'", connection))
            {
                command.ExecuteNonQuery();
            }

            // 删除（Delete）
            using (OleDbCommand command = new OleDbCommand("DELETE FROM Employees WHERE FirstName = 'John'", connection))
            {
                command.ExecuteNonQuery();
            }
        }
    }
}

using System;
using System.Data;
using System.Data.OleDb;

class Program
{
    static void Main()
    {
        string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\yourdatabase.mdb;";
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            connection.Open();
            OleDbTransaction transaction = connection.BeginTransaction();

            try
            {
                OleDbCommand command = connection.CreateCommand();
                command.Transaction = transaction;

                command.CommandText = "INSERT INTO Table1 (Column1) VALUES ('Value1')";
                command.ExecuteNonQuery();

                command.CommandText = "INSERT INTO Table2 (Column2) VALUES ('Value2')";
                command.ExecuteNonQuery();

                // 提交事务
                transaction.Commit();
                Console.WriteLine("Both records are written to database.");
            }
            catch (Exception ex)
            {
                // 回滚事务
                transaction.Rollback();
                Console.WriteLine("There was an error, transaction was rolled back.");
                Console.WriteLine(ex.Message);
            }
        }
    }
}

using System;
using System.Data;
using System.Data.OleDb;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\yourdatabase.mdb;";
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            await connection.OpenAsync();

            using (OleDbCommand command = new OleDbCommand("SELECT * FROM Employees", connection))
            {
                using (OleDbDataReader reader = (OleDbDataReader)await command.ExecuteReaderAsync())
                {
                    while (await reader.ReadAsync())
                    {
                        Console.WriteLine($"{reader["FirstName"]} {reader["LastName"]}");
                    }
                }
            }
        }
    }
}

using System;
using System.Data;
using System.Data.OleDb;

class Program
{
    static void Main()
    {
        string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\yourdatabase.mdb;";
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            connection.Open();

            using (OleDbCommand command = new OleDbCommand("GetEmployeeDetails", connection))
            {
                command.CommandType = CommandType.StoredProcedure;

                // 添加输入参数
                command.Parameters.AddWithValue("@EmployeeId", 1);

                // 如果存储过程有返回值
                command.Parameters.Add(new OleDbParameter("@ReturnValue", OleDbType.VarChar, 100));
                command.Parameters["@ReturnValue"].Direction = ParameterDirection.Output;

                command.ExecuteNonQuery();

                // 读取输出参数的值
                string result = command.Parameters["@ReturnValue"].Value.ToString();
                Console.WriteLine("Result: " + result);
            }
        }
    }
}