ASP.NET期中筆記

• runat="server" 前端與後端連接
• if (!IsPostBack) 頁面第一次載入的時候初始化頁面的預設設定
• AutoPostBack="TRUE|FALSE" 自動重新整理 (e.g. DropDownList選取時直接執行)
• protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
         mybody.Attributes["bgcolor"] = ((DropDownList)sender).SelectedValue;
     }
  DropDownList1選擇之後更換背景顏色
• void AddOne(ref int n)
    {
          n = n + 1;
    }
  引數加上ref為call by reference
• js:document.getElementById('mydiv').innerHTML = "Hello World!"
  可覆蓋掉重複的字
• js:let img = document.createElement("img")
     img.src = "poker/" + p + s + ".gif"
     document.body.appendChild(img)
  建立圖片物件，給與指定路徑並加入到網頁
• DropDownList1.DataSource = new string[] { "s", "c", "d", "c" };
  DropDownList1.DataBind();
  RadioButtonList1.DataSource = new string[] { "s", "c", "d", "c" };
  RadioButtonList1.DataBind();
  繫結資料並DataBind
• defaultbutton="Button1"
  進入頁面直接按Enter可執行Button1
• defaultfocus="TextBox1"
  進入頁面可直接在TextBox1輸入
• onFocus="this.select()"
  在textbox加入可自動選取文字
• coverprice = Convert.ToInt32(Regex.Match(cbEng_cover.Text, @"-?\d+").Value);
  可將一串文字裡的數字抓出來並轉換成整數
  
• <asp:FileUpload ID="FileUpload1" runat="server" />
  <asp:HyperLink ID="HyperLink1" runat="server" Visible="False">HyperLink</asp:HyperLink>
  protected void Button1_Click(object sender, EventArgs e)
  {
    if (FileUpload1.HasFile)
    {
      FileUpload1.SaveAs(Server.MapPath("uploads/") + FileUpload1.FileName);
      HyperLink1.Text = FileUpload1.FileName;
      HyperLink1.NavigateUrl = "uploads/" + FileUpload1.FileName;
      HyperLink1.Visible = true;
     }
  }
  FileUpload與HyperLink元件實現上傳檔案及顯示檔案內容
• DropDownList ddl = new DropDownList();
  Button btn = new Button();
  btn.Click += new System.EventHandler(this.ddl_SelectedIndexChanged);
  div1.Controls.Add(ddl);
  div1.Controls.Add(btn);
  protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
  {
      //DropDownList ddl = (DropDownList)sender;
      Response.Output.Write("You choose {0}", ddl.SelectedValue);
  }
  宣告DropDownList與Button物件並加入至div1，ddl_SelectedIndexChanged設置給btn.Click
• if (!IsPostBack)
  {
    string[] eng = { "heady", "invariably", "illiterate", "lavish", "incessant", "lethal", "incumbent", "lucrative", "indignant", "ludicrous", "inherent", "malicious", "initial", "mock", "integral", "mundane", "intricate", "optional", "invalid", "perennial" };
    string chiString = "飄飄然的, 必定地不變地, 不識字的, 鋪張的奢華的, 不停的, 致命的, 現職的, 可獲利的, 憤憤不平的, 可笑的滑稽的, 固有的, 懷惡意的, 首度的, 煞有其事的, 必須的不可或缺的, 世俗的, 複雜的, 可選擇的, 無效的作廢的, 長期間持續的";
    string[] chi = chiString.Split(new char[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
    for (int i = 0; i < eng.Length; i++)
    {
        DropDownList1.Items.Add(new ListItem(eng[i], chi[i]));
        BulletedList1.Items.Add(new ListItem(eng[i], String.Format("https://tw.dictionary.search.yahoo.com/search?p={0}", eng[i])));
    }
    DropDownList1.Items.Insert(0, new ListItem("請選擇單字", ""));
  }
  將chiString利用,切割成陣列，再加入DropDownList1& BulletedList1
  protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
  {
      Response.Output.Write("{0}的中文{1}", DropDownList1.SelectedItem.Text, DropDownList1.SelectedValue);
      Response.Redirect(String.Format("https://tw.dictionary.search.yahoo.com/search?p={0}", DropDownList1.SelectedItem.Text));
  }
  帶出中文及英文，跳轉頁面
• ListBox
  lbFamiliar.Items[i].Selected
  lbUnFamiliar.Items.Add(lbFamiliar.Items[i]);
  lbFamiliar.Items.RemoveAt(i);
  
• Calendar & jQuery Datepicker
• <input type="datetime-local" required id ="mydatetime1" runat="server" />
  將input種類設定為calendar，required必須輸入
• <appSettings>
     <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
  </appSettings>
  使用以下功能需在Web.config加入上述程式
  RequiredFieldValidator 確保使用者有輸入資料
  ControlToValidate="TextBox1" 監控哪個物件
  Display="Dynamic" 驗證失敗時，驗證訊息的空間會動態新增至頁面
  ErrorMessage="姓名是必要欄位" 驗證失敗時的錯誤訊息
  ValidationGroup="first 設定驗證群組
  
• RangeValidator 確保使用者輸入資料在範圍內
  MaximumValue="120" 最大值(包含)
  MinimumValue="0" 最小值(包含)
  Type="Integer" 資料型態
  
• ValidationSummary 可顯示設定群組之錯誤訊息
  
• RegularExpressionValidator 確保格式正確
  ValidationExpression 此屬性可調整想對照的格式(e.g. email)
  
• CompareValidator 比較與另外一個物件的值是否相同，例如確認密碼
  ControlToCompare="TextBox4" 與TextBox4比較值
  
• CustomValidator 使用使用者自己定義的驗證
  ClientValidationFunction="checkintroduction" 指定自己定義的驗證
  <script>
  function checkintroduction(sender, args) {
      if (args.Value.length < 20)
          args.IsValid = false //指出網頁驗證是否成功
      }
  }
  </script>
  
• <form method="get" action="https://tw.dictionary.search.yahoo.com/search;" accept-charset="utf-8">
      <input type="text" name="p" required autofocus onclick="this.select()" />
      <input type="submit" />
  </form>
  html get 英語單字查詢
• <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True">
      <asp:ListItem Value="https://tw.dictionary.search.yahoo.com/search?p=">Yahho</asp:ListItem>
      <asp:ListItem Value="https://dictionary.cambridge.org/zht/詞典/英語-漢語-繁體/">Canbridge</asp:ListItem>
  </asp:DropDownList>
  protected void Button1_Click(object sender, EventArgs e)
  {
      Response.Redirect(string.Format("{0}{1}", DropDownList1.SelectedValue, TextBox1.Text));
  }
  DropDownList可選擇Yahooc或cambridge在輸入單字可跳轉到查詢頁面
• input autofocus 頁面載入時會自動在輸入框
• TextBox TextMode="Password" 輸入文字有密碼效果
• GET 與 POST 的差異
  
• <form id="form1" action="test2.aspx" method="post" runat="server">
      <div>
            <asp:Panel ID="Panel1" runat="server">
                   <asp:TextBox ID="a" runat="server"></asp:TextBox>
                   <br />
                   <asp:TextBox ID="b" runat="server"></asp:TextBox>
                   <br />
                   <asp:Button ID="Button1" runat="server" Text="Button" />
            </asp:Panel>
      </div>
  </form>
  利用post方法傳送資料到test2.aspx
  public partial class test2 : System.Web.UI.Page
  {
       protected void Page_Load(object sender, EventArgs e)
       {
          Response.Output.Write("{0}, {1}", Request["a"], Request["b"]);
       }
  }
  在text2.aspx獲取值
• HiddenField hf = new HiddenField();
  hf.Value = 5.ToString();
  hf.ID = "cnt2";
  mydiv.Controls.Add(hf);
  HiddenField儲存需要在向伺服器的傳送間保持的值
  
• ASP.NET保存資訊 Application、Session、Cookie、Cache、ViewState的差異
• Session["text"] = text.Text;
  Session["selected"] = selected;
  Session可以存放值或整個object
  
• Session["text"]
  DropDownList ddl = (DropDownList)Session["selected"];
  string selected = ddl.SelectedValue;
  Session獲取值或object
  
• Response.Redirect("page1.aspx");
  導到page1.aspx頁面
  
• Random r = new Random();
  for (int i = cards.Length - 1; i >= 1; i--)
  {
      int x = r.Next(i+1);
      if (x != i)
       {
           int tmp = cards[x];
           cards[x] = cards[i];
           cards[i] = tmp;
       }
  }
  洗牌演算法
  
• for (int i = 0; i < 5; i++)
  {
      TextBox tb = new TextBox();
      tb.Width = Unit.Point(5 * 8);
      tb.ID = "user" + i;
      Label lb1 = new Label();
      lb1.Text = "</br>";
      mydiv.Controls.Add(tb);
      mydiv.Controls.Add(lb1);
  }
  Button btn = new Button();
  btn.Text = "submit";
  mydiv.Controls.Add(btn);
  動態產生TextBox與Button
  
• int n2 = Convert.ToInt32(Request["cnt2"]);
  int n = Int32.Parse(Literal2.Text);
  string轉int
  
• Literal3.Text =bingo.ToString();
  int轉string