ASP.NET學習筆記三
阿新 • • 發佈：2020-12-26
1、控制元件的屬性和方法
|
屬性 |
描述 |
|
ClientID |
返回控制元件在瀏覽器端生成的識別符號 |
|
Controls |
返回當前控制元件的子控制元件集合 |
|
EnableViewState |
返回或設定當前控制元件是否使用檢視狀態功能 |
|
ID |
返回或設定當前控制元件在頁面中的唯一標識 |
|
Page |
返回當前頁面的父頁面引用 |
|
Parent |
返回當前控制元件父控制元件的引用,即其所在的容器控制元件 |
|
Visible |
返回或設定當前控制元件是否呈現在頁面中 |
2、單選按鈕與複選框
3、控制權轉移控制元件
<h3>控制權轉移控制元件</h3>
<asp:Button ID="btn1" runat="server" Text="普通按鈕" PostBackUrl="~/server.aspx" CommandArgument="hello" />
<asp:LinkButton ID="lbtn2" runat="server" Text="超連結按鈕" PostBackUrl="~/server.aspx" CommandArgument="hello"/>
<asp:ImageButton ID="
protected void Page_Load(objectsender, EventArgs e) { txt.CssClass = "txt"; //txt.Text = DateTime.Now.ToString(); hl1.Target = "_blank"; }
四、FileUpload控制元件（實現檔案的上傳和下載）
<form id="form1" runat="server" enctype="multipart/form-data"> <div> 頭像：<input type="file" name="uploadFile" /> <asp:Button ID="btnupload" runat="server" Text="上傳檔案" OnClick="btnupload_Click" /> </div> </form>
protected void btnupload_Click(object sender, EventArgs e) { //獲得客戶端上傳的檔案集合 HttpFileCollection files = Request.Files; //獲得指定的檔案物件 HttpPostedFile file = files[0]; if (file.FileName == "") { Response.Write("<script>alert('請選擇檔案上傳');</script>"); return; } //if(file.ContentLength>10*1024) //{ // Response.Write("<script>alert('上傳的檔案不能超過10KB，請壓縮後上傳');</script>"); // return; //} //組裝伺服器端路徑 string serverPath = "~/uploadFolder/" + file.FileName; serverPath = Server.MapPath(serverPath);//上傳的路徑必須是物理路徑 file.SaveAs(serverPath);//實現上傳 Response.Write("<script>alert('上傳成功');</script>"); }
後端程式碼也可以為：
protected void btnupload_Click(object sender, EventArgs e) { if(!myFile.HasFile) { Response.Write("<script>alert('請選擇檔案上傳');</script>"); return; } HttpPostedFile file = myFile.PostedFile; //if (file.ContentLength > 10 * 1024) //{ // Response.Write("<script>alert('上傳的檔案不能超過10KB，請壓縮後上傳');</script>"); // return; //} //組裝伺服器端路徑 string serverPath = "~/uploadFolder/" + file.FileName; serverPath = Server.MapPath(serverPath);//上傳的路徑必須是物理路徑 file.SaveAs(serverPath);//實現上傳 Response.Write("<script>alert('上傳成功');</script>"); }
批量上傳檔案程式碼：
<form id="form1" runat="server" enctype="multipart/form-data"> <div> <input type="button" name="btnaddFile" value="點選上傳" id="btnaddFile" /> <asp:Button ID="btnuploadFile" runat="server" Text="批量上傳" OnClick="btnuploadFile_Click" /> </div> <div id="files"> </div> </form> <script src="scripts/jquery.js"></script> <script> $(function () { var i = 1; $("#btnaddFile").click(function () { var file = $("<input type='file' class='file' name='file" + i + "'/><br/>"); $("#files").append(file); i++; }) }) </script>
protected void btnuploadFile_Click(object sender, EventArgs e) { if (Request.Files.Count == 0) return; int count = 0; for(int i = 0; i < Request.Files.Count; i++) { HttpPostedFile file = Request.Files[i]; string name = file.FileName; if(name!="") { string path = "~/uploadFolder/" + name; path = Server.MapPath(path); file.SaveAs(path); count++; } } Response.Write("<script>alert('成功上傳" + count + "個檔案')</script>"); }
5、下載檔案
<form id="form1" runat="server"> <div> <asp:HyperLink ID="hlDownLoad" runat="server" Text="點選下載"/><br /> <asp:Button ID="btnDownLoad" runat="server" Text="點選下載" OnClick="btnDownLoad_Click"/> </div> </form>
protected void Page_Load(object sender, EventArgs e) { //下載時提代檔案的虛擬路徑或相對路徑 //hlDownLoad.NavigateUrl = "~/uploadFolder/邏輯題.doc"; //hlDownLoad.Text = "邏輯題.doc"; //hlDownLoad.NavigateUrl = "~/uploadFolder/test.xlsx"; //hlDownLoad.Text = "test.xlsx"; //hlDownLoad.NavigateUrl = "~/uploadFolder/test.txt"; //hlDownLoad.Text = "test.txt"; hlDownLoad.NavigateUrl = "~/uploadFolder/book.jpg"; hlDownLoad.Text = "book.jpg"; } protected void btnDownLoad_Click(object sender, EventArgs e) { string fileName = "book.jpg"; string path = "~/uploadFolder/" + fileName; path = Server.MapPath(path); byte[] bytes = null; using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read)) { //建立位元組陣列緩衝區 bytes= new byte[fs.Length]; //讀取檔案到位元組陣列中 fs.Read(bytes, 0, bytes.Length); } //通知瀏覽器檔案是以附件形式下載，而不是直接開啟的 Response.AddHeader("Content-Disposition", "attachment;Filename="+fileName); //將緩衝區的位元組陣列下載到本地 Response.BinaryWrite(bytes); //停止當前頁的執行 Response.End(); }
6、droplist和listbox控制元件
<form id="form1" runat="server"> <div> 班級：<asp:DropDownList ID="drpClass" runat="server" OnSelectedIndexChanged="drpClass_SelectedIndexChanged" Width="150"> </asp:DropDownList> <br /> 學員：<asp:ListBox ID="lstStudents" runat="server" Width="150" SelectionMode="Multiple"> </asp:ListBox> </div> </form> <script src="scripts/jquery.js"></script> <script> $(function () { $("#drpClass").change(function () { var cno=$(this).val();//班級編號 if (cno != "-99") $("#form1").submit();//手動提交表單 else $("#lstStudents").get(0).options.length = 0; //清空下拉列表 }) }) </script>
private void LoadClass() { List<@class> lstClass = [email protected](); lstClass.Insert(0,new @class { className = "--請選擇班級--", classNo = "-99" }); #region 方法1：使用Items屬性 //foreach (var c in lstClass) //{ // ListItem item = new ListItem { Text = c.className, Value = c.classNo }; // drpClass.Items.Add(item); //} #endregion #region 方法2：使用DataSource屬性 drpClass.DataSource = lstClass;//設定資料來源 drpClass.DataTextField = "className";//顯示的屬性是資料來源中的哪個欄位或屬性 drpClass.DataValueField = "classNo";//隱藏的屬性是資料來源中的哪個欄位或屬性 drpClass.DataBind();//將當前控制元件的資料繫結至控制元件中，一定要呼叫 #endregion } /// <summary> /// 班級下拉列表選項改變時觸發 /// </summary> protected void drpClass_SelectedIndexChanged(object sender, EventArgs e) { string cno = drpClass.SelectedValue;//獲取當前選中班級的班級編號 LoadStudents(cno); } /// <summary> /// 根據班級編號載入學員 /// </summary> /// <param name="cno">班級編號</param> private void LoadStudents(string cno) { List<student> lststus = db.student.Where(s => s.classNo == cno).ToList(); lstStudents.DataSource = lststus; lstStudents.DataTextField = "sname"; lstStudents.DataValueField = "sno"; lstStudents.DataBind(); }