(Restrict the size of file upload in asp.net) – Khi xây dựng chức năng Upload file lên Server, khi không giới hạn dung lượng file nếu người dùng Upload file quá lớn trang Web thường hay xuất hiện lỗi. Vậy làm sao để có thể kiểm tra trước dung lượng file trước khi Upload lên Server?
Bài viết dưới đây sẽ giúp chúng ta giải quyết vấn đề kiểm soát kích thước file upload, nếu dung lượng file vượt quá cho phép một cảnh báo sẽ xuất hiện. Ngoài ra chương trình còn kiểm tra dung lượng thư mục (Folder), nếu thư mục còn dung lượng cho phép việc Upload file mới được thực hiện thành công.

Nghe những bài hát đỉnh nhất về Thấy cô giáo - Nghe trên Youtube

- B1: Tạo Project trong Microsoft Visual Studio 2010

- B2: Mở file Default.aspx dưới dạng HTML và nhập mã HTML

C# Code

<%@ PageTitle="Restrict the size of file uploads in ASP.NET" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="RestrictSizeofFileUpload._Default" %>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

<tr>

<td>

<divclass="panel panel-default">

<divclass="panel-heading">

<asp:label id="lblHeader" runat="server" Text="Restrict the size of file uploads"></asp:label>

</div>

<divclass="panel-body">

<tr>

<asp:label id="plFileName"runat="server"Text="File Name (*)"></asp:label>

</td>

<td>

<asp:FileUpload ID="FileUpload"runat="server"Width="150px"/><br />

<asp:label id="lblAllowed"runat="server"></asp:label><br />

<asp:CustomValidator id="valFile"runat="server"CssClass="NormalRed"ValidationGroup="validate"OnServerValidate="valFile_ServerValidate"ErrorMessage="You Must Upload A File" Display="Dynamic"></asp:CustomValidator>

</td>

</tr>

<tr>

<asp:label id="lblMessage"runat="server"Visible="false"></asp:label><br />

</td>

</tr>

</table>

</div>

<divclass="modal-footer">

<asp:LinkButton id="cmdUpload"runat="server"CssClass="btn btn-small" OnClick="cmdUpload_Click" ValidationGroup="validate" Causesvalidation="true">

</asp:LinkButton>

</div>

</td>

</tr>

</table>

</asp:Content>

VB.NET Code

<%@ PageTitle="Restrict the size of file uploads in ASP.NET" Language="vb" MasterPageFile="~/Site.Master" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="RestrictSizeofFileUpload._Default" %>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

<tr>

<td>

<divclass="panel panel-default">

<divclass="panel-heading">

<asp:label id="lblHeader" runat="server" Text="Restrict the size of file uploads"></asp:label>

</div>

<divclass="panel-body">

<tr>

<asp:label id="plFileName"runat="server"Text="File Name (*)"></asp:label>

</td>

<td>

<asp:FileUpload ID="FileUpload"runat="server"Width="150px"/><br />

<asp:label id="lblAllowed"runat="server"></asp:label><br />

<asp:CustomValidator id="valFile"runat="server"CssClass="NormalRed"ValidationGroup="validate"ErrorMessage="You Must Upload A File" Display="Dynamic"></asp:CustomValidator>

</td>

</tr>

<tr>

<asp:label id="lblMessage"runat="server"Visible="false"></asp:label><br />

</td>

</tr>

</table>

</div>

<divclass="modal-footer">

<asp:LinkButton id="cmdUpload"runat="server"CssClass="btn btn-small" ValidationGroup="validate" Causesvalidation="true">

</asp:LinkButton>

</div>

</td>

</tr>

</table>

</asp:Content>

- B3: Viết Code cho file Default.aspx

C# Code

//Visit http://www.laptrinhdotnet.com for more ASP.NET Tutorials

using Microsoft.VisualBasic;

using System;

using System.Collections;

using System.Collections.Generic;

using System.Data;

using System.IO;

using System.Diagnostics;

using System.Web.UI;

using System.Web;

using System.Web.UI.WebControls;

namespace RestrictSizeofFileUpload

{

public partial class _Default : System.Web.UI.Page

{

#region"Private Members"

private stringFilePath = "";

private longRestrictFileSize = 2;

private longRestrictFolderSize = 100;

#endregion

#region"Private Methods"

public longGetFolderSize(string DirPath, bool IncludeSubFolders = true)

{

DirectoryInfo objDir = newDirectoryInfo(DirPath);

DirectoryInfo objFolder = null;

longTotalSize = 0;

FileInfo objFileInfo = null;

foreach (FileInfoobjFileInfo_loopVariable in objDir.GetFiles())

{

objFileInfo = objFileInfo_loopVariable;

TotalSize += objFileInfo.Length;

}

if (IncludeSubFolders)

{

foreach (DirectoryInfoobjFolder_loopVariable inobjDir.GetDirectories())

{

objFolder = objFolder_loopVariable;

TotalSize += GetFolderSize(objFolder.FullName);

}

return TotalSize;

}

protected stringUploadFile(FileUpload file)

{

string fileName = null;

string fileExtension = "";

fileExtension = Path.GetExtension(file.FileName).Replace(".", "");

fileName = file.FileName.Substring(file.FileName.LastIndexOf("\\\\") + 1);

fileName = fileName.Substring(0, fileName.LastIndexOf(fileExtension)) + fileExtension;

FilePath = FilePath + fileName;

file.SaveAs(FilePath);

return fileName;

}

private voidSetFilePath()

{

FilePath = MapPath("~/Upload/");

if (!Directory.Exists(FilePath))

{

Directory.CreateDirectory(FilePath);

}

#endregion

#region"Event Handles"

protected voidPage_Load(object sender, System.EventArgs e)

{

try

{

if (!IsPostBack)

{

lblAllowed.Text = "Allowed only max " + RestrictFileSize + " MB to upload";

}

catch

{

}

protected voidcmdUpload_Click(object sender, System.EventArgs e)

{

if (Page.IsValid)

{

try

{

SetFilePath();

if (FileUpload.HasFile)

{

long FolderSize = 0;

FolderSize = (GetFolderSize(FilePath, true) / 1024) / 1024;

if (FolderSize < RestrictFolderSize)

{

//1MB=1024KB

long filesize = ((FileUpload.PostedFile.ContentLength) / 1024) / 1024;

if (filesize < RestrictFileSize)

{

UploadFile(FileUpload);

lblMessage.Text = "File uploaded successfully.";

lblMessage.ForeColor = System.Drawing.Color.Green;

lblMessage.Visible = true;

}

else

{

lblMessage.Text = "You are allowed to upload more then "+ RestrictFileSize + " MB.";

lblMessage.ForeColor = System.Drawing.Color.Red;

lblMessage.Visible = true;

}

else

{

lblMessage.Text = "The File Exceeds The Amount Of Disk Space You Currently Have Available.";

lblMessage.ForeColor = System.Drawing.Color.Red;

lblMessage.Visible = true;

}

catch

{

}

protected voidvalFile_ServerValidate(object source, ServerValidateEventArgs args)

{

if (FileUpload.PostedFile != null)

{

if (FileUpload.PostedFile.ContentLength > 0)

{

args.IsValid = true;

}

else

{

args.IsValid = false;

}

#endregion

}

VB.NET Code

'Visit http://www.laptrinhdotnet.com for more ASP.NET Tutorials

Imports System.IO

Namespace RestrictSizeofFileUpload

Public Class _Default

Inherits System.Web.UI.Page

#Region "Private Members"

Private FilePath As String = ""

Private RestrictFileSize AsLong = 2

Private RestrictFolderSize AsLong = 100

#End Region

#Region "Private Methods"

Function GetFolderSize(ByValDirPath As String, Optional ByValIncludeSubFolders As Boolean= True) As Long

Dim objDir As DirectoryInfo = NewDirectoryInfo(DirPath)

Dim objFolder As DirectoryInfo

Dim TotalSize As Long

DimobjFileInfo As FileInfo

For Each objFileInfo In objDir.GetFiles()

TotalSize += objFileInfo.Length

If IncludeSubFolders Then

For EachobjFolder In objDir.GetDirectories()

TotalSize += GetFolderSize(objFolder.FullName)

End If

Return TotalSize

End Function

Protected FunctionUploadFile(ByVal file AsFileUpload) AsString

Dim fileName As String

Dim fileExtension As String = ""

fileExtension = Replace(Path.GetExtension(file.FileName), ".", "")

fileName = file.FileName.Substring(file.FileName.LastIndexOf("\\") + 1)

fileName = fileName.Substring(0, fileName.LastIndexOf(fileExtension)) & fileExtension

FilePath = FilePath + fileName

file.SaveAs(FilePath)

Return fileName

End Function

Private SubSetFilePath()

FilePath = MapPath("~/Upload/")

If Not Directory.Exists(FilePath) Then

Directory.CreateDirectory(FilePath)

End If

End Sub

#End Region

#Region "Event Handles"

Protected SubPage_Load(ByVal sender AsObject, ByVal e As System.EventArgs) Handles Me.Load

Try

If Page.IsPostBack = False Then

lblAllowed.Text = "Allowed only max " & RestrictFileSize & " MB to upload"

End If

Catch ex As Exception

End Try

End Sub

Private SubcmdUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) HandlescmdUpload.Click

If Page.IsValid Then

Try

SetFilePath()

If FileUpload.HasFile Then

Dim FolderSize As Long

FolderSize = (GetFolderSize(FilePath, True) / 1024) / 1024

If FolderSize < RestrictFolderSize Then

'1MB=1024KB

Dim filesize As Long = ((FileUpload.PostedFile.ContentLength) / 1024) \ 1024

If filesize < RestrictFileSize Then

UploadFile(FileUpload)

lblMessage.Text = "File uploaded successfully."

lblMessage.ForeColor = System.Drawing.Color.Green

lblMessage.Visible = True

Else

lblMessage.Text = "You are allowed to upload more then "& RestrictFileSize & " MB."

lblMessage.ForeColor = System.Drawing.Color.Red

lblMessage.Visible = True

End If

Else

lblMessage.Text = "The File Exceeds The Amount Of Disk Space You Currently Have Available."

lblMessage.ForeColor = System.Drawing.Color.Red

lblMessage.Visible = True

End If

Catch ex AsException

End Try

End If

End Sub

Private SubvalFile_ServerValidate(ByVal source As System.Object, ByVal args AsSystem.Web.UI.WebControls.ServerValidateEventArgs) Handles valFile.ServerValidate

Try

If Not(FileUpload.PostedFile Is Nothing) Then

If (FileUpload.PostedFile.ContentLength > 0) Then

args.IsValid = True

Return

End If

args.IsValid = False

Catch exc As Exception

End Try

End Sub

#End Region

End Class

End Namespace

Chúc các bạn thành công!

Quang Bình

Kiểm soát kích thước file và thư mục Upload lên Server trong Asp.net

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