哈希表的使用

Hashtable hashtable = new Hashtable();

hashtable.ContainsValue(tmp);//判断哈希表中有没有tmp

hashtable.add(tmp,tmp);//加入哈希表

DataSet的使用

SqlDataAdapter sda = new SqlDataAdapter(sqlCount, myconn);

DataSet ds = new DataSet();

sda.Fill(ds);

获取ds里的值

ds.Tables[0].Rows[0]["字段"]  或者 ds.Tables[0].Rows[0][0]

SqlConnection myconn = new SqlConnection(conn);

            myconn.Open();

            SqlDataAdapter sda = new SqlDataAdapter(sql, myconn);

            DataSet ds = new DataSet();

            sda.Fill(ds, "Ticket");

            dataGridView1.DataSource = ds;

            dataGridView1.DataMember = "Ticket";
dataGridView1.Rows[i].Cells["字段"].Value.ToString()；

 //将excel表导入到dataSet

         public DataSet getXSLData(string filepath)

         {

             string strCon = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filepath + ";Extended Properties=\"Excel 12.0;HDR=YES;\"";

             System.Data.OleDb.OleDbConnection Conn = new System.Data.OleDb.OleDbConnection(strCon);

             string strCom = "SELECT * FROM [Sheet1$]";

             Conn.Open();

             System.Data.OleDb.OleDbDataAdapter myCommand = new System.Data.OleDb.OleDbDataAdapter(strCom, Conn);

             DataSet ds = new DataSet();

             myCommand.Fill(ds, "[Sheet1$]");

             Conn.Close();

             return ds;

         }

OpenFileDialog ofd = new OpenFileDialog();

            ofd.Filter = "Microsoft Excel files(*.xls)|*.xls;*.xlsx";//过滤一下，只要表格格式的

            ofd.RestoreDirectory = true;

            ofd.FilterIndex = ;

            ofd.AddExtension = true;

            ofd.CheckFileExists = true;

            ofd.CheckPathExists = true;

            ofd.ShowHelp = true;//是否显示帮助按钮

            if (ofd.ShowDialog() == DialogResult.OK)

            {

                this.textBox1.Text = ofd.FileName;

            }