Need a challenge.

[Begginnerdev]

Hello my fellow Daniwebers.

I am to ask for some ideas for a challenge.

I want a good challenge for my skills, and even help expand my skills

Please post your challenge below.

Thanks,
Begginnerdev

[adam_k]

I've got a feeling that this will end up in a "Build Windows or Office" type of thread, where even if you do build a basic Excel type of thing with formulas and everything they will still argue that Excel has VBA or that you don't have macro security and miss the whole picture.

If I'm out of topic, then consider it a challenge to keep this thread (or article as it's called nowadays) from becoming what I've just described.

[Unhnd_Exception]

Make an image viewer control. I attached a pic of an example I put together.

The control should do the following.

Display a thumbnail strip of images. When the thumbnail is clicked the full image is displayed in the center.

The control should only get what is needed. If the image source has 1,000 images the only images that should be processed are the thumbnails visible on the screen and the full image.

So you will need to get a count of all the images in the source and then determine which indexes are needed in the thumbnail strip and only get those images.

Make the control unaware of its source. Create a method on the control to start the image viewing that takes in an Interface.

For example,
A method named ShowImages(byval reader as ISlideReader)

The ISlideReader interface should have a couple of methods that the image viewer would need such as GetThumbnails, GetCount, and GetImage. When the ImageViewer needed its data it would call reader.GetCount, reader.GetThumbnails, and reader.GetImage.

After you have made the interface then create three classes that implemented the interface

For example

Public class SqlImageReader
implements ISlideReader

..... implementation
End Class

Public class FolderImageReader
implements ISlideReader
.....
End Class

Public class WebImageReader
implements ISlideReader
....
End Class

With those 3 implementations you should be able to pass in an instance to ShowImages to the ImageViewer and it will display images from a database, folder system, or even a web page with out having to change any code in the ImageViewer control.

Example: ImageViewerControl1.ShowImages(New WebImageReader("a web url"))

And go ahead and make an orientation property for the thumbnails. Left, Right, Top, Bottom.

Make a hot and selected state for the thumbnails.

You could even make the thumbnail strip draggable.

Hope it makes since. And looks like something you want to do. At the end, you will have a versatile image control you could plug in for any situation you needed.

[Begginnerdev]

Awesome, thanks Exception. I will give it a try.

[Begginnerdev]

This is how far I have gotten as of right now;

Imports System.Data.OleDb
Imports System.IO

Public Class main_form
    Implements IPictures

    Private curDir As String

    Private Sub OpenDirectoryToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles OpenDirectoryToolStripMenuItem.Click
        If FolderBrowserDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
            If FolderBrowserDialog1.SelectedPath <> "" Then
                If IO.Directory.Exists(FolderBrowserDialog1.SelectedPath) = True Then
                    Me.curDir = FolderBrowserDialog1.SelectedPath & "/"

                    CreatePanels(getPictures(IPictures.SourceType.Local, Me.curDir))
                End If
            End If
        End If
    End Sub

    Public Function CreateIndexedList(path As String) As System.Collections.ArrayList Implements IPictures.CreateIndexedList
        Try
            If IO.Directory.Exists(path) Then
                Dim al As New ArrayList
                Dim dir As New IO.DirectoryInfo(path)
                Dim fi As IO.FileInfo

                For Each fi In dir.GetFiles()
                    al.Add(fi.FullName)
                Next
                Return al
            Else
                MsgBox("Path was incorrect.")
                Return Nothing
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Function getPictureCount(path As String) As Integer Implements IPictures.getPictureCount
        Try
            If IO.Directory.Exists(path) Then
                Dim i As Integer
                Dim dir As New IO.DirectoryInfo(path)
                Dim fi As IO.FileInfo
                For Each fi In dir.GetFiles()
                    i += 1
                Next
                Return i
            Else
                MsgBox("Path was incorrect.")
                Return Nothing
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Function getPictures(ST As IPictures.SourceType, Optional ByVal Path As String = "", Optional ByVal dbCon As OleDb.OleDbConnection = Nothing, Optional ByVal webAdd As String = "") As Image() Implements IPictures.getPictures
        Try
            If ST = IPictures.SourceType.Local And Path <> "" Then
                If IO.Directory.Exists(Path) Then
                    Dim i As Integer = 0
                    Dim dir As New IO.DirectoryInfo(Path)
                    Dim fi As IO.FileInfo
                    Dim im(getPictureCount(Path)) As Image
                    For Each fi In dir.GetFiles()
                        If fi.Extension = ".jpeg" Or fi.Extension = ".bmp" Or fi.Extension = ".png" Or fi.Extension = ".tiff" Then
                            Dim str As New IO.FileStream(fi.FullName, IO.FileMode.Open)
                            im(i) = Drawing.Image.FromStream(str)
                            str.Flush()
                        End If
                    Next
                    Return im
                Else
                    MsgBox("Path was incorrect.")
                    Return Nothing
                End If
            ElseIf ST = IPictures.SourceType.Database And dbCon IsNot Nothing Then

            ElseIf ST = IPictures.SourceType.Web And webAdd <> "" Then

            Else

            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Sub CreatePanels(imgs() As System.Drawing.Image) Implements IPictures.CreatePanels
        Try
            For i = 0 To imgs.Count - 1
                Dim p As New Panel

                p.Size = New Size(128, 128)
                p.BackColor = SystemColors.ActiveCaptionText
                p.BackgroundImage = imgs(i)
                p.BackgroundImageLayout = ImageLayout.Stretch
                ImagesFlowLayoutPanel.Controls.Add(p)
                AddHandler p.DoubleClick, AddressOf Panel_DoubleClick
            Next

        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Private Sub Panel_DoubleClick(sender As Object, e As EventArgs)
        ImagePanel.BackgroundImage = CType(sender, Panel).BackgroundImage
    End Sub

    End Class

Public Interface IPictures

    Enum SourceType
        Local = 1
        Database = 2
        Web = 3
    End Enum

    Function getPictures(ST As SourceType, Optional ByVal Path As String = "", Optional ByVal dbCon As OleDb.OleDbConnection = Nothing, Optional ByVal webAdd As String = "") As Image()

    Function getPictureCount(path As String) As Integer

    Function CreateIndexedList(path As String) As ArrayList

    Sub CreatePanels(imgs As Image())

End Interface

[GaryR]

How about something for the non coding world. Something just for fun or hobbies. Things like control for turning things on or off, model train layouts, stuff like that. Sounds simple, but is it? Like anything else, it's as simple as you want to make it.

[Begginnerdev]

Have some code here, but I seem to be having a problem.

The program throws a null reference exception in the GetImage function when it runs normally. Here is the funny thing, when I cycle through it in debug mode, it works fine!?

Here is what I have so far:

Imports System.Data.OleDb
Imports System.IO
Imports System.Net

Public Class main_form
    Implements IPictures
    Private curDir As String
    Private selectedControl As Integer
    Private webAddress As String = ""
    Private wb As New WebBrowser
    Private hd As HtmlDocument
    Private hc As HtmlElementCollection
    Private he As HtmlElement

    Public Property Website As String
        Get
            Return Me.webAddress
        End Get
        Set(value As String)
            Me.webAddress = value
        End Set
    End Property

    Private Sub OpenDirectoryToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles OpenDirectoryToolStripMenuItem.Click
        If FolderBrowserDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
            If FolderBrowserDialog1.SelectedPath <> "" Then
                If IO.Directory.Exists(FolderBrowserDialog1.SelectedPath) = True Then
                    Me.curDir = FolderBrowserDialog1.SelectedPath & "/"

                    CreatePanels(getPictures(IPictures.SourceType.Local, Me.curDir))
                End If
            End If
        End If
    End Sub

    Public Function CreateIndexedList(path As String) As System.Collections.ArrayList Implements IPictures.CreateIndexedList
        Try
            If IO.Directory.Exists(path) Then
                Dim al As New ArrayList
                Dim dir As New IO.DirectoryInfo(path)
                Dim fi As IO.FileInfo

                For Each fi In dir.GetFiles()
                    al.Add(fi.FullName)
                Next
                Return al
            Else
                MsgBox("Path was incorrect.")
                Return Nothing
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Function getPictureCount(path As String) As Integer Implements IPictures.getPictureCount
        Try
            If IO.Directory.Exists(path) Then
                Dim i As Integer
                Dim dir As New IO.DirectoryInfo(path)
                Dim fi As IO.FileInfo
                For Each fi In dir.GetFiles()
                    i += 1
                Next
                Return i
            Else
                MsgBox("Path was incorrect.")
                Return Nothing
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Function getPictures(ST As IPictures.SourceType, Optional ByVal Path As String = "", Optional ByVal dbCon As OleDb.OleDbConnection = Nothing, Optional ByVal webAdd As String = "") As ArrayList Implements IPictures.getPictures
        Try
            If ST = IPictures.SourceType.Local And Path <> "" Then
                If IO.Directory.Exists(Path) Then
                    Dim i As Integer = 0
                    Dim dir As New IO.DirectoryInfo(Path)
                    Dim fi As IO.FileInfo
                    Dim im As New ArrayList
                    For Each fi In dir.GetFiles()
                        If fi.Extension = ".jpeg" Or fi.Extension = ".bmp" Or fi.Extension = ".png" Or fi.Extension = ".tiff" Then
                            im.Add(Drawing.Image.FromFile(fi.FullName))
                        End If
                    Next
                        Return im
                Else
                    MsgBox("Path was incorrect.")
                    Return Nothing
                End If
            ElseIf ST = IPictures.SourceType.Database And dbCon IsNot Nothing Then

            ElseIf ST = IPictures.SourceType.Web And webAdd <> "" Then
                Dim im As New ArrayList
                wb.Navigate(webAdd)
                hd = wb.Document
                hc = hd.Images
                For Each he As HtmlElement In hc
                    Dim imgurl As String = he.GetAttribute("src")
                    im.Add(getPictureFromWeb(imgurl))
                Next
                Return im
            Else

            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return Nothing
        End Try
    End Function

    Public Sub CreatePanels(imgs As ArrayList) Implements IPictures.CreatePanels
        Try
            If imgs IsNot Nothing Then
                For i = 0 To imgs.Count - 1
                    Dim p As New Panel

                    p.Size = New Size(128, 128)
                    p.BackColor = SystemColors.ActiveCaptionText
                    p.BackgroundImage = CType(imgs(i), Image)
                    p.BackgroundImageLayout = ImageLayout.Stretch

                    If i > 0 Then
                        p.Location = New Point(ImagesFlowLayoutPanel.Controls(i - 1).Location.X + 140, ImagesFlowLayoutPanel.Controls(i - 1).Location.Y)
                    End If

                    ImagesFlowLayoutPanel.Controls.Add(p)
                    AddHandler p.DoubleClick, AddressOf Panel_DoubleClick
                Next
            Else
                Return
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Private Sub Panel_DoubleClick(sender As Object, e As EventArgs)
        ImagePanel.BackgroundImage = CType(sender, Panel).BackgroundImage
        selectedControl = ImagesFlowLayoutPanel.Controls.IndexOf(CType(sender, Panel))
    End Sub

    Private Sub PreviousButton_Click(sender As System.Object, e As System.EventArgs) Handles PreviousButton.Click
        If selectedControl > 0 Then
            ImagePanel.BackgroundImage = ImagesFlowLayoutPanel.Controls(selectedControl - 1).BackgroundImage
            selectedControl = ImagesFlowLayoutPanel.Controls.IndexOf(ImagesFlowLayoutPanel.Controls(selectedControl - 1))
        End If
    End Sub

    Private Sub NextButton_Click(sender As System.Object, e As System.EventArgs) Handles NextButton.Click
        If selectedControl < ImagesFlowLayoutPanel.Controls.Count - 1 Then
            ImagePanel.BackgroundImage = ImagesFlowLayoutPanel.Controls(selectedControl + 1).BackgroundImage
            selectedControl = ImagesFlowLayoutPanel.Controls.IndexOf(ImagesFlowLayoutPanel.Controls(selectedControl + 1))
        End If
    End Sub

    Private Sub FirstButton_Click(sender As System.Object, e As System.EventArgs) Handles FirstButton.Click
        ImagePanel.BackgroundImage = ImagesFlowLayoutPanel.Controls(0).BackgroundImage
        selectedControl = 0
    End Sub

    Private Sub LastButton_Click(sender As System.Object, e As System.EventArgs) Handles LastButton.Click
        ImagePanel.BackgroundImage = ImagesFlowLayoutPanel.Controls(ImagesFlowLayoutPanel.Controls.Count - 1).BackgroundImage
        selectedControl = ImagesFlowLayoutPanel.Controls.IndexOf(ImagesFlowLayoutPanel.Controls(ImagesFlowLayoutPanel.Controls.Count - 1))
    End Sub

    Private Sub OpenWebSiteToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles OpenWebSiteToolStripMenuItem.Click
    website_dialog.ShowDialog()
        If Me.Website <> "" Then
            CreatePanels(getPictures(IPictures.SourceType.Web, , , Me.Website))
        End If
    End Sub

    Public Function getPictureFromWeb(path As String) As System.Drawing.Image Implements IPictures.getPictureFromWeb
        Try
            Dim wc As New WebClient
            Dim ib() As Byte = wc.DownloadData(path)

            Dim ims As New MemoryStream(ib)
            Dim pic As Image = Image.FromStream(ims)

            Return pic
        Catch ex As Exception
            MsgBox(ex.Message)
        Return Nothing
        End Try
    End Function

        Private Sub ClearToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles ClearToolStripMenuItem.Click
            ImagesFlowLayoutPanel.Controls.Clear()
            ImagePanel.Controls.Clear()
        End Sub
End Class


Public Interface IPictures

    Enum SourceType
    Local = 1
    Database = 2
    Web = 3
    End Enum

    Function getPictures(ST As SourceType, Optional ByVal Path As String = "", Optional ByVal dbCon As OleDb.OleDbConnection = Nothing, Optional ByVal webAdd As String = "") As ArrayList

    Function getPictureCount(path As String) As Integer

    Function CreateIndexedList(path As String) As ArrayList

    Function getPictureFromWeb(path As String) As Image

    Sub CreatePanels(imgs As ArrayList)

End Interface

[Begginnerdev]

The problem is the web browser hasn't loaded the page correctly.

Has anyone had any experience with delaying code execution until a browser has loaded the document?

I have used the web browsers readystate in a while loop:

While wb.ReadyState <> WebBrowserReadyState.Complete
End While

but it sits in an infinite loop.

[Begginnerdev]

Closing a dead thread.

Sorry to leave it open for so long.