Can not upload photos: NullReferenceException [duplicate] - asp.net

Question

This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 8 years ago.
Hello everyone I've been struggling with this error message for days:
Here is the error message:
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 7:
Line 8: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Line 9: UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString()
Line 10: cannotUploadImageMessage.Visible = False
Line 11: End Sub
Source File: C:\Users\Collins\Documents\Visual Studio 2005\WebSites\living to please god world\PhotoAdmin\Default.aspx.vb Line: 9
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
PhotoAdmin_Default.Page_Load(Object sender, EventArgs e) in C:\Users\Collins\Documents\Visual Studio 2005\WebSites\living to please god world\PhotoAdmin\Default.aspx.vb:9
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627
This is my complete code to upload photos. Can someone help me please?
Imports System.Data
Imports System.IO
Imports System.Data.SqlClient
Partial Class PhotoAdmin_Default
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString()
cannotUploadImageMessage.Visible = False
End Sub
Protected Sub dvPictureInsert_ItemInserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertedEventArgs) Handles dvPictureInsert.ItemInserted
'If the record was successfully inserted, save the picture
If e.AffectedRows > 0 Then
'Determine the maximum pictureID for this user
Dim results As DataView = CType(maxPictureIDDataSource.Select(DataSourceSelectArguments.Empty), DataView)
Dim pictureIDJustAdded As Integer = CType(results(0)(0), Integer)
'Reference the FileUpload control
Dim imageUpload As FileUpload = CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)
If imageUpload.HasFile Then
Dim baseDirectory As String = Server.MapPath("~/UploadedImages/")
imageUpload.SaveAs(baseDirectory & pictureIDJustAdded & ".jpg")
End If
End If
If e.Exception Is Nothing Then
' Use the AffectedRows property to determine whether the
' record was inserted. Sometimes an error might occur that
' does not raise an exception, but prevents the insert
' operation from completing.
If e.AffectedRows = 1 Then
MessageLabel.Text = "Record inserted successfully."
Else
MessageLabel.Text = "An error occurred during the insert operation."
' Use the KeepInInsertMode property to remain in insert mode
' when an error occurs during the insert operation.
e.KeepInInsertMode = True
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception has already been handled.
e.ExceptionHandled = True
e.KeepInInsertMode = True
End If
End Sub
Protected Sub dvPictureInsert_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertEventArgs) Handles dvPictureInsert.ItemInserting
Dim cancelInsert As Boolean = False
Dim imageUpload As FileUpload =CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)
If Not imageUpload.HasFile Then
cancelInsert = True
Dim acceptedExtensions = New String() {".jpg", ".png", ".gif"}
If Not acceptedExtensions.Contains(imageUpload.FileName, StringComparer.OrdinalIgnoreCase) Then
cancelInsert = True 'Invalid image file!
End If
Else
Dim image As System.Drawing.Image = System.Drawing.Image.FromStream(imageUpload.PostedFile.InputStream)
If image.Width > 1300 Or image.Height > 950 Then
cancelInsert = True
End If
End If
If cancelInsert Then
e.Cancel = True
cannotUploadImageMessage.Visible = True
End If
'Set the UserId value to the currently logged on user's ID
e.Values("UserId") = Membership.GetUser().ProviderUserKey
'Set the UploadedOn value to the current date/time
e.Values("UploadedOn") = DateTime.Now
End Sub
Protected Sub gvPictures_RowDeleted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeletedEventArgs) Handles gvPictures.RowDeleted
Dim baseDirectory As String = Server.MapPath("~/UploadedImages/")
Dim fileName As String = baseDirectory & e.Keys("PictureID") & ".jpg"
File.Delete(fileName)
End Sub
Protected Sub gvPictures_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles gvPictures.RowUpdating
e.NewValues("UserId") = Membership.GetUser().ProviderUserKey
End Sub
End Class

Answer 1

Are you sure Membership.GetUser() is actually returning a user?
You are authenticated and not an anonymous user, correct? You should add a null check or a check to make sure they are authenticated first. I believe you can use User.Identity.IsAuthenticated

Answer 2

Just while editing for formatting I see line 9 has to do with membership and a control. Gut instinct is saying you're not logged in or that control doesn't exist.
Place a breakpoint at your line 9, run the site in debug, and see if the Membership.GetUser() or UserIdValue are null.