How to upload a file to a Web server in ASP.NET by using Visual Basic .NET

IN THIS TASK

• SUMMARY

  • Create the ASP.NET application
  • Create the Data directory
  • Modify the WebForm1.aspx page
  • Add the upload code to the WebForm1.aspx.vb code-behind file
  • Test the application
  • Upload larger files
  • Complete code listing

    • WebForm1.aspx
    • WebForm1.aspx.vb
• REFERENCES

Create the ASP.NET application

1. Start Microsoft Visual Studio .NET.
2. On the File menu, point to New, and then click Project.
3. In the New Project dialog box, click Visual Basic Projects under Project Types, and then click ASP.NET Web Application under Templates.
4. In the Location box, type the URL to create the project. For this example, type http://localhost/VBNetUpload, which creates the default project name of VBNetUpload. Notice that the WebForm1.aspx file loads in the Designer view of Visual Studio .NET.

Create the Data directory

1. In the Solution Explorer window of Visual Studio .NET, right-click VBNetUpload, point to Add, and then click New Folder. By default, a new folder that is named NewFolder1 is created.
2. To change the folder name to Data, right-click NewFolder1, click Rename, and then type Data.
3. Start Windows Explorer, and then locate the Data file system folder that you created in step 2. By default, this folder is located in the following folder:

   C:\Inetpub\wwwroot\VBNetUpload\Data
4. To change the security settings to grant write permissions to the Data directory, right-click Data, and then click Properties.
5. In the Data Properties dialog box, click the Security tab, and then click Add.
6. In the Select Users or Groups dialog box, click the ASPNET account, and then click Add. Click OK to close the Select Users or Groups dialog box.
7. Click the aspnet_wp account (computername\ASPNET) account or the Network Service account if you are using Microsoft Internet Information Services (IIS) 6.0, and then click to select the Allow check boxes for the following permissions:

   • Read and Execute
   • List Folder Contents
   • Read
   • Write

   
   Click to clear any other Allow and Deny check boxes.
8. Click OK to close the Data Properties dialog box. You have successfully modified the Data directory permissions to accept user uploaded files.

Modify the WebForm1.aspx page

1. Return to the open instance of Visual Studio .NET. WebForm1.aspx should be open in the Designer window.
2. To view the HTML source of the WebForm1.aspx page, right-click WebForm1.aspx in the Designer window, and then click View HTML Source.
3. Locate the following HTML code, which contains the <form> tag:

   <form id="Form1" method="post" runat="server">
   					

4. Add the enctype="multipart/form-data" name-value attribute to the <form> tag as follows:

   <form id="Form1" method="post" enctype="multipart/form-data" runat="server">
   					

5. After the opening <form> tag, add the following code:

   <INPUT type=file id=File1 name=File1 runat="server" />
   <br>
   <input type="submit" id="Submit1" value="Upload" runat="server" />
   					

6. Verify that the HTML <form> tag appears as follows:

   <form id="Form1" method="post" enctype="multipart/form-data" runat="server">
   <INPUT type=file id=File1 name=File1 runat="server" />
   <br>
   <input type="submit" id="Submit1" value="Upload" runat="server" />
   </form>
   					

Add the upload code to the WebForm1.aspx.vb code-behind file

1. On the View menu, click Design.
2. Double-click Upload. Visual Studio opens the WebForm1.aspx.vb code-behind file and automatically generates the following method code:

   Private Sub Submit1_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit1.ServerClick
   
   End Sub
   					

3. Verify that the following code exists at the class level of the WebForm1.vb file:

   Protected WithEvents Submit1 As System.Web.UI.HtmlControls.HtmlInputButton
   Protected WithEvents File1 As System.Web.UI.HtmlControls.HtmlInputFile
   						

   If this code does not exist in the file, add the code into the file after the following line:

   Inherits System.Web.UI.Page
   					

4. Locate the following code:

   Private Sub Submit1_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit1.ServerClick
   					

5. Press ENTER to add a blank line, and then add the following code:

   If Not File1.PostedFile Is Nothing And File1.PostedFile.ContentLength > 0 Then
   
   Dim fn As String =                      System.IO.Path.GetFileName(File1.PostedFile.FileName)
   Dim SaveLocation as String = Server.MapPath("Data") & "\" & fn
   Try
      		File1.PostedFile.SaveAs(SaveLocation)
      		Response.Write("The file has been uploaded.")
   Catch Exc As Exception
    	Response.Write("Error: " & Exc.Message)
   End Try
   Else
   Response.Write("Please select a file to upload.")
   End If
   						

   This code first verifies that a file has been uploaded. If no file was selected, you receive the "Please select a file to upload" message. If a valid file is uploaded, its file name is extracted by using the System.IO namespace, and its destination is assembled in a SaveAs path. After the final destination is known, the file is saved by using the File1.PostedFile.SaveAs method. Any exception is trapped, and the exception message is displayed on the screen.
6. Verify that the Submit1 subroutine appears as follows:

   Private Sub Submit1_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit1.ServerClick
   	If Not File1.PostedFile Is Nothing And File1.PostedFile.ContentLength > 0 Then
               Dim fn As String = System.IO.Path.GetFileName(File1.PostedFile.FileName)
               Dim SaveLocation as String = Server.MapPath("Data") & "\" & fn
               Try
                   File1.PostedFile.SaveAs(SaveLocation)
                   Response.Write("The file has been uploaded.")
               Catch Exc As Exception
                   Response.Write("Error: " & Exc.Message)
               End Try
           Else
               Response.Write("Please select a file to upload.")
           End If
   End Sub
   					

Test the application

1. On the Build menu, click Build Solution.
2. In Solution Explorer, right-click WebForm1.aspx, and then click View in Browser.
3. After WebForm1.aspx opens in the browser, click Browse.
4. In the Choose File dialog box, select a file that is smaller than 4 megabytes (MB), and then click Open.
5. To upload the file, click Upload. Notice that the file uploads to the Web server and that you receive the "The file has been uploaded" message.
6. Return to the open instance of Windows Explorer, and then locate the Data directory.
7. Verify that the file has been uploaded to the Data directory.

Upload larger files

<httpRuntime 
executionTimeout="90" 
maxRequestLength="4096"
useFullyQualifiedRedirectUrl="false" 
minFreeThreads="8" 
minLocalRequestFreeThreads="4"
appRequestQueueLimit="100"
/>
				

Complete code listing

WebForm1.aspx

<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="VBNetUpload.WebForm1"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
  <HEAD>
    <title>WebForm1</title>
    <meta name="GENERATOR" content="Microsoft Visual Studio.NET 7.0">
    <meta name="CODE_LANGUAGE" content="Visual Basic 7.0">
    <meta name=vs_defaultClientScript content="JavaScript">
    <meta name=vs_targetSchema content="http://schemas.microsoft.com/intellisense/ie5">
  </HEAD>
  <body MS_POSITIONING="GridLayout">

    <form id="Form1" enctype="multipart/form-data" method="post" runat="server">

<INPUT type=file id=File1 name=File1 runat="server" >
<br>
<input type="submit" id="Submit1" value="Upload" runat="server" NAME="Submit1">


    </form>

  </body>
</HTML>
				

WebForm1.aspx.vb

Public Class WebForm1
    Inherits System.Web.UI.Page
    Protected WithEvents File1 As System.Web.UI.HtmlControls.HtmlInputFile
    Protected WithEvents Submit1 As System.Web.UI.HtmlControls.HtmlInputButton

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: This method call is required by the Web Form Designer
        'Do not modify it using the code editor.
        InitializeComponent()
    End Sub

#End Region

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
    End Sub

    Private Sub Submit1_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit1.ServerClick

        If Not File1.PostedFile Is Nothing And File1.PostedFile.ContentLength > 0 Then
            Dim fn As String = System.IO.Path.GetFileName(File1.PostedFile.FileName)
            Dim SaveLocation as String = Server.MapPath("Data") & "\" & fn
            Try
                File1.PostedFile.SaveAs(SaveLocation)
                Response.Write("The file has been uploaded.")
            Catch Exc As Exception
                Response.Write("Error: " & Exc.Message)
            End Try
        Else
            Response.Write("Please select a file to upload.")
        End If

    End Sub
End Class
				

• The page cannot be displayed.
• Server Application is Unavailable

  In the event log, the error message will be similar to the following:

  aspnet_wp.exe (PID:PIDNumber) was recycled because memory consumption exceeded the SizeLimit MB (Percentage percent of available RAM).
  

• Exception of type System.OutOfMemoryException was thrown.