ASP. NET FileUpload controls upload pictures and preview pictures

Page code:

<form id="Form1"runat="Server"> <div> <asp:fileupload id="FileUpload1"runat="Server"/> <asp:button id="Button1"runat="Server"text="Upload"Width="54px"onclick="Button1_Click"/> <asp:label id="Label1"runat="Server"text=""style="color:red"></asp:Label> <asp:image runat="Server"Id="Image1"style="z-index:102; left:20px; Position:absolute ;Top:49px"width="73px"/></div> </form>

Background code:

Using system;using system.data;using system.configuration;using system.web;using system.web.security;using System.web.ui;using system.web.ui.webcontrols;using system.web.ui.webcontrols.webparts;using System.web.ui.htmlcontrols;namespace web.file{public partial class WebForm1:System.Web.UI.Page {protected void page_l Oad (object sender, EventArgs e) {} #region File upload///<summary>//File upload///</summary> protected void B Utton1_click (object sender, EventArgs e) {if (Fileupload1.filename = = "") {this.    Label1.Text = "Upload file cannot be empty";   Return   } bool Fileisvalid = FALSE; If the upload file is confirmed, determine if the file type meets the requirements if (this. Fileupload1.hasfile) {//Gets the suffix of the uploaded file String fileextension = System.IO.Path.GetExtension (this. Fileupload1.filename).    ToLower ();    String[] restrictextension = {". gif", ". jpg", ". bmp", ". png"}; Determine if the file type meets the requirements for (int i = 0; i < restrictextension.length; i++) {if (fileextension = = Restrictextension[i ]) {fileisvalid = TruE }//If the file type meets the requirements, call the SaveAs method to implement the upload and display the relevant information if (Fileisvalid = = true) {//upload file is greater than 10M if (fileupload1.post Edfile.contentlength > (Ten * 1024x768)) {this.       Label1.Text = "Upload file too large";      Return } try {this.       Image1.imageurl = "~/file/" + fileupload1.filename; This.       Fileupload1.saveas (Server.MapPath ("~/file/") + Fileupload1.filename); This.      Label1.Text = "File upload succeeded!"; } catch {this. Label1.Text = "File upload failed!"      "; } finally {}} else {this.     Label1.Text = "Only files with the. gif,.jpg,.bmp,.png suffix can be uploaded"; }}}} #endregion}}

Web. config configuration:

<!--because FileUpload control uploads up to 4M, if you want to upload larger files, change the size of maxRequestLength--><configuration> <system.web> < Compilation debug="true"targetframework="4.0"/> "2.0"Maxrequestlength="10485760"executiontimeout="3600"apprequestqueuelimit="10000"/> </system.web></configuration>

ASP. NET FileUpload controls upload pictures and preview pictures