Solved

System.NullReferenceException was unhandled

Posted on 2013-01-12
9
490 Views
Last Modified: 2013-01-12
I have an error that I cannot resolve. “System.NullReferenceException was unhandled”


What I am trying to do is select images from a combo box so they can be displayed in a picture box. The variable "dra" is the trouble maker for sure.


The Code:

Public Class Orders

    Private m_path As String = "C:\Users\Joe\Documents\Visual Studio 2012\Projects\sa_Shipping-Receiving\My Project\Images\VL"

    Private Sub Orders_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        LoadPictures()

    End Sub

 


   Private Sub LoadPictures()

        Dim dir As New IO.DirectoryInfo(m_path)
        Dim files As IO.FileInfo() = dir.GetFiles("*.jpg")
        Dim dra As IO.FileInfo

        'List the names of all files in the specified directory for each dra in files.



-----The line of code directly below is where the error occurred   (dra.Name). -----

        ComboBox1.Items.Add(dra.Name)




        On Error Resume Next
    End Sub



    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged

        If Not (ComboBox1.SelectedItem Is Nothing) Then
            Me.PictureBox1.Image = Image.FromFile(IO.Path.Combine(m_path, ComboBox1.SelectedItem.ToString))
        End If

    End Sub

    End Class


Thank you for any help.
0
Comment
Question by:jampost
  • 6
  • 2
9 Comments
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 38771032
Where are you initializing the variable dra at?
0
 

Author Comment

by:jampost
ID: 38771053
Kaufmed,

I have been thinking that was the problem. I am not sure how to initial ize it.
0
 
LVL 75

Assisted Solution

by:käµfm³d 👽
käµfm³d   👽 earned 250 total points
ID: 38771057
I suppose that would depend on what lies within, "List the names of all files in the specified directory for each dra in files."
0
 

Author Comment

by:jampost
ID: 38771073
Kaufmed,

  Are you saying list the file names in the code?
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 

Author Comment

by:jampost
ID: 38771076
The only reason I'm asking is because it is 207 files.
0
 

Author Comment

by:jampost
ID: 38771083
They are all jpg files. I thought about getting it to pull up one of them to initialize it, but I couldn't get it to work.
0
 

Author Comment

by:jampost
ID: 38771089
They are all in a single directory, and I can list them in the code if that is what needs to be done.
0
 
LVL 85

Accepted Solution

by:
Mike Tomlinson earned 250 total points
ID: 38771107
You need to iterate over the files in your "files" array:
    Private Sub LoadPictures()
        Dim dir As New IO.DirectoryInfo(m_path)
        Dim files As IO.FileInfo() = dir.GetFiles("*.jpg")
        Dim dra As IO.FileInfo
        For Each dra In files
            ComboBox1.Items.Add(dra.Name)
        Next
    End Sub

Open in new window

0
 

Author Closing Comment

by:jampost
ID: 38771290
kaufmed was giving me the answer, but I wasn't familiar with the terminology. Idle_Mind made it a bit clearer.  Thank you both.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction As chip makers focus on adding processor cores over increasing clock speed, developers need to utilize the features of modern CPUs.  One of the ways we can do this is by implementing parallel algorithms in our software.   One recent…
Whether you've completed a degree in computer sciences or you're a self-taught programmer, writing your first lines of code in the real world is always a challenge. Here are some of the most common pitfalls for new programmers.
This Micro Tutorial will teach you how to censor certain areas of your screen. The example in this video will show a little boy's face being blurred. This will be demonstrated using Adobe Premiere Pro CS6.
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…

867 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

14 Experts available now in Live!

Get 1:1 Help Now