ASP.NET中檔案上傳與下載
檔案下載
ASP.NET依託.net framework類庫,封裝了大量的功能,使得上傳檔案非常簡單,主要有以下三種基本方法。
方法一:用Web控制元件FileUpload,上傳到網站根目錄。
Test.aspx關鍵程式碼:
- <formid="form1"runat="server">
- <asp:FileUploadID="FileUpload1"runat="server"/>
- <asp:ButtonID="Button1"runat="server"Text="上傳"OnClick="Button1_Click"/>
-
<asp:Label
- </form>
Test.aspx.cs關鍵程式碼:
- protectedvoid Button1_Click(object sender, EventArgs e)
- {
- if (FileUpload1.HasFile)
- {
- FileUpload1.SaveAs(Server.MapPath("~/") + FileUpload1.FileName);
-
Label1.Text = "上傳成功!"
- }
- }
方法二:用Html控制元件HtmlInputFile,上傳到網站根目錄。
Test.aspx關鍵程式碼:
- <formid="form1"runat="server">
- <inputtype="file"id="file1"runat="server"/>
- <asp:ButtonID="Button1"runat="server"Text="上傳"OnClick="Button1_Click"/>
-
<asp:LabelID="Label1"runat="server"Text=""Style="color: Red"
- </form>
Test.aspx.cs關鍵程式碼:
- protectedvoid Button1_Click(object sender, EventArgs e)
- {
- if (file1.PostedFile.ContentLength > 0)
- {
- file1.PostedFile.SaveAs(Server.MapPath("~/") + Path.GetFileName(file1.PostedFile.FileName));
- Label1.Text = "上傳成功!";
- }
- }
方法三:用Html元素<input type="file" …/>,通過Request.Files上傳到網站根目錄。
Test.aspx關鍵程式碼:
- <formid="form1"runat="server"enctype="multipart/form-data">
- <inputtype="file"name="file"/>
- <asp:ButtonID="Button1"runat="server"Text="上傳"OnClick="Button1_Click"/>
- <asp:LabelID="Label1"runat="server"Text=""Style="color: Red"></asp:Label>
- </form>
Test.aspx.cs關鍵程式碼:
- protectedvoid Button1_Click(object sender, EventArgs e)
- {
- if (Request.Files["file"].ContentLength > 0)
- {
- Request.Files["file"].SaveAs(Server.MapPath("~/") + Path.GetFileName(Request.Files["file"].FileName));
- Label1.Text = "上傳成功!";
- }
- }
注意兩個區別:
一:FileUpload.FileName獲取客戶端上傳檔名(不帶路徑),而file1.PostedFile.FileName 和Request.Files["file"].FileName在不同瀏覽器下情況不同:IE8下獲得的是客戶端上傳檔案的完全限定名(帶路徑),谷歌、蘋果等瀏覽器下則仍為檔名(不帶路徑)。
二:FileUpload控制元件有HasFile屬性,用於判斷使用者是否選擇了上傳檔案,而後面兩種方法則需要通過判斷上傳檔案大小ContentLength屬性,當用戶沒有選擇上傳檔案時,該屬性值為0。
可以看出FileUpload封裝程度更高,但靈活性也稍差。
檔案下載:
protected
void Button1_Click(object sender, EventArgs e)
{
/*
微軟為Response物件提供了一個新的方法TransmitFile來解決使用Response.BinaryWrite
下載超過400mb的檔案時導致Aspnet_wp.exe程序回收而無法成功下載的問題。
程式碼如下:
*/
Response.ContentType = "application/x-zip-compressed";
Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");
string filename = Server.MapPath("DownLoad/aaa.zip");
Response.TransmitFile(filename);
}
//WriteFile實現下載
protected void Button2_Click(object sender, EventArgs e)
{
/*
using System.IO;
*/
string fileName ="aaa.zip";//客戶端儲存的檔名
string filePath=Server.MapPath("DownLoad/aaa.zip");//路徑
FileInfo fileInfo = new FileInfo(filePath);
Response.Clear();
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
Response.AddHeader("Content-Length", fileInfo.Length.ToString());
Response.AddHeader("Content-Transfer-Encoding", "binary");
Response.ContentType = "application/octet-stream";
Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
Response.WriteFile(fileInfo.FullName);
Response.Flush();
Response.End();
}
//WriteFile分塊下載
protected void Button3_Click(object sender, EventArgs e)
{
string fileName = "aaa.zip";//客戶端儲存的檔名
string filePath = Server.MapPath("DownLoad/aaa.zip");//路徑
System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);
if (fileInfo.Exists == true)
{
const long ChunkSize = 102400;//100K 每次讀取檔案,只讀取100K,這樣可以緩解伺服器的壓力
byte[] buffer = new byte[ChunkSize];
Response.Clear();
System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
long dataLengthToRead = iStream.Length;//獲取下載的檔案總大小
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
while (dataLengthToRead > 0 && Response.IsClientConnected)
{
int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//讀取的大小
Response.OutputStream.Write(buffer, 0, lengthRead);
Response.Flush();
dataLengthToRead = dataLengthToRead - lengthRead;
}
Response.Close();
}
}
//流方式下載
protected void Button4_Click(object sender, EventArgs e)
{
string fileName = "aaa.zip";//客戶端儲存的檔名
string filePath = Server.MapPath("DownLoad/aaa.zip");//路徑
//以字元流的形式下載檔案
FileStream fs = new FileStream(filePath, FileMode.Open);
byte[] bytes = new byte[(int)fs.Length];
fs.Read(bytes, 0, bytes.Length);
fs.Close();
Response.ContentType = "application/octet-stream";
//通知瀏覽器下載檔案而不是開啟
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName,
System.Text.Encoding.UTF8));
Response.BinaryWrite(bytes);
Response.Flush();
Response.End();
}