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System.NullReferenceException was unhandled

Posted on 2013-01-12
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494 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.
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Question by:jampost
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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."
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Author Comment

by:jampost
ID: 38771073
Kaufmed,

  Are you saying list the file names in the code?
0
 

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.
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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

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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.
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