CType NullReferenceException when trying to upload a picture

Question

Can someone help me correct this code? I am receiving the following error:

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 21:   'Determine the maximum pictureID for this user
Line 22:   Dim results As DataView = CType(maxPictureIDDataSource.Select(DataSourceSelectArguments.Empty), DataView)
Line 23:   Dim pictureIDJustAdded As Integer = CType(results(0)(0), Integer)
Line 24:   'Reference the FileUpload control
Line 25:   Dim imageUpload As FileUpload = CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)

Source File: C:\Users\Collins\Documents\Visual Studio 2005\WebSites\living to please god world\PhotoAdmin\Default.aspx.vb    Line: 23

and the red error line is on this line of code:

Line 23:   Dim pictureIDJustAdded As Integer = CType(results(0)(0), Integer)

Does anyone have an idea of where I can start to look?

Peladao · Accepted Answer · 2011-01-26 21:18:24Z

3

The element results(0) may not exist or element results(0)(0) may not exist (depending on what the previous statement returns) and therefore return Nothing.

So you should first check these things before using CType on them, for instance:

Dim pictureIDJustAdded As Integer
If results(0) IsNot Nothing AndAlso results(0).Length > 0 Then
  pictureIDJustAdded = CType(results(0)(0), Integer)
Else
  'report error
End If

edited Jan 26, 2011 at 21:18

answered Jan 26, 2011 at 9:30

Peladao

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2 Comments

onfire4JesusCollins Over a year ago

Hello thanks for the help. Can you pls show me were to insert your above code? Here is the full codes for the picture upload below

Peladao Over a year ago

After line 22 (Dim pictureIDJustAdded As Integer is now included in the code fragment), and replacing your line 23.

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