羅 朝淇的部落格

屬性：Tables用來取得DataSet中所包含的資料表集合
方法：ReadXml()讀取XML內容到DataSet
            WriteXml()把DataSet的內容寫成XML

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient; //新增命名空間 for SQL Server

namespace DataSetForSQL_ex
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        DataSet GlobalDS;//宣告GlobalDS為全域變數其型別為DataSet
        //載入資料
        private void button1_Click(object sender, EventArgs e)
        {
            string ConnString;
            ConnString = "Data Source =127.0.0.1;Initial catalog = school2;" +
                             "User id = sa;Password = 123";

            string selectCmd = "SELECT * FROM Student";

            //Step 1：開啟資料庫連接，準備與資料庫進行溝通和存取
            SqlConnection conn = new SqlConnection(ConnString);
            conn.Open();

            // Step 2：資料配接器的宣告，來執行SQL敘述並開啟資料庫連接
            SqlDataAdapter da = new SqlDataAdapter(selectCmd, conn);

            // Step 3：宣告DataSet，用DataAdapter將SQL執行結果填入DataSet所指定的表格中
            DataSet ds = new DataSet();
            da.Fill(ds, "Student");

            GlobalDS = ds;//將ds指定給GlobalDS

            // Step 4：把DataSet中的資料表拿來當DataGridView控制項的資料來源
            dataGridView1.DataSource = ds.Tables["Student"];
            dataGridView1.AutoResizeColumns(); //自動調整欄位大小

            // Step 5：關閉連接物件與資料配接器物件來釋放物件所佔用的資源
            conn.Close();
            da.Dispose();
        }
        //取出DataSet
        private void button2_Click(object sender, EventArgs e)
        {
            if (GlobalDS == null)  //用NULL來判斷，是否為空
            {
                MessageBox.Show("請先點選[載入資料]鈕");
            }
            else
            {
                string MsgString = "";
                foreach (DataTable dt in GlobalDS.Tables) //將DataTable的資料表內容逐一取出
                {
                    foreach (DataColumn col in dt.Columns)
                    {
                        MsgString = MsgString + col.ColumnName + "\t";
                    }
                    MsgString = MsgString + "\r\n";

                    foreach (DataRow row in dt.Rows)
                    {

                        foreach (DataColumn col in dt.Columns)
                        {
                            MsgString = MsgString + row[col] + "\t";
                        }
                        MsgString = MsgString + "\r\n";
                    }

                    MessageBox.Show(this,MsgString,"好學生清單");
                } //foreach(dt)

            }
        }
    }
}