asked on

New Storage

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using Windows.Storage;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace New_Storage
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
StorageLibrary activelibrary = null;
StorageLibrary publicvideoslibrary = null;
StorageLibrary publicmusiclibrary = null;

StorageLibrary publicpictureslibrary = null;

IStorageFolder mainfolder = null;

IStorageItem item = null;

IStorageFile file = null;

ListBoxItem itm = null;

TextBox publictextbox = null;

public MainPage()
{
this.InitializeComponent();

this.Loading += MainPage_Loading;

this.RightTapped += MainPage_RightTapped;

this.DoubleTapped += MainPage_DoubleTapped;

libraries_listbox.SelectionChanged += Libraries_listbox_SelectionChanged;

libraries_listbox.Items.Insert(0, "videos");

libraries_listbox.Items.Insert(1, "pictures");

libraries_listbox.Items.Insert(2, "music");

items_listbox.SelectionChanged += Items_listbox_SelectionChanged;

items_listbox.DoubleTapped += Items_listbox_DoubleTapped;

ListViewItem createfolderitem = new ListViewItem();

createfolderitem.Content = "Create Folder:";

ListViewItem createfileitem = new ListViewItem();

createfileitem.Content = "Create File:";

ListViewItem deleteitem = new ListViewItem();

deleteitem.Content = "Delete:";

ListViewItem renameitem = new ListViewItem();

renameitem.Content = "Rename:";

TextBox t = new TextBox();

listviewitem.Items.Add(createfolderitem);

listviewitem.Items.Add(createfileitem);

listviewitem.Items.Add(deleteitem);

listviewitem.Items.Add(renameitem);

listviewitem.Items.Add(t);

listviewitem.Visibility = Visibility.Collapsed;

listviewitem.SelectionChanged += Listviewitem_SelectionChanged;

publictextbox = t;

}

private async void Listviewitem_SelectionChanged(object sender, SelectionChangedEventArgs e)
{

if (listviewitem.SelectedItem == listviewitem.Items[0])
{
await mainfolder.CreateFolderAsync(publictextbox.Text);

listviewitem.Visibility = Visibility.Collapsed;
}
if (listviewitem.SelectedItem == listviewitem.Items[1])
{
await mainfolder.CreateFileAsync(publictextbox.Text);

listviewitem.Visibility = Visibility.Collapsed;
}
if (listviewitem.SelectedItem == listviewitem.Items[2])
{
item = await mainfolder.GetItemAsync(items_listbox.SelectedValue.ToString());

await item.DeleteAsync(StorageDeleteOption.Default);

listviewitem.Visibility = Visibility.Collapsed;
}
if (listviewitem.SelectedItem == listviewitem.Items[3])
{
item = await mainfolder.GetItemAsync(items_listbox.SelectedValue.ToString());

await item.RenameAsync(publictextbox.Text);

listviewitem.Visibility = Visibility.Collapsed;

}
}

private async void Items_listbox_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
{
[b] item = await mainfolder.GetItemAsync(itm.Content.ToString());
[/b]
if (item.GetType() == mainfolder.GetType())
{
mainfolder = await mainfolder.GetFolderAsync(item.Name);

foreach (IStorageItem itm in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(itm);
}
}
if (item.GetType() == publicpictureslibrary.SaveFolder.GetType())
{
mainfolder = await mainfolder.GetFolderAsync(item.Name);

items_listbox.Items.Clear();

foreach (IStorageItem itm in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(itm.Name);
}
}
}

private void Items_listbox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
itm = items_listbox.SelectedItem as ListBoxItem;

}

private void MainPage_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
{

}

private async void Libraries_listbox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (libraries_listbox.SelectedItem == libraries_listbox.Items[0])
{
activelibrary = publicvideoslibrary;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach(IStorageItem item in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(item.Name);
}

}

else if (libraries_listbox.SelectedItem == libraries_listbox.Items[1])
{
activelibrary = publicpictureslibrary;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach (IStorageItem item in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(item.Name);
}
}
else if (libraries_listbox.SelectedItem == libraries_listbox.Items[2])
{
activelibrary = publicmusiclibrary;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach (IStorageItem item in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(item.Name);
}
}
}

private void MainPage_RightTapped(object sender, RightTappedRoutedEventArgs e)
{
listviewitem.Visibility = Visibility.Visible;
}

private async void MainPage_Loading(FrameworkElement sender, object args)
{
StorageLibrary videoslibrary = await StorageLibrary.GetLibraryAsync(KnownLibraryId.Videos);

publicvideoslibrary = videoslibrary;

publicvideoslibrary.DefinitionChanged += Publicvideoslibrary_DefinitionChanged;

StorageLibrary musiclibrary = await StorageLibrary.GetLibraryAsync(KnownLibraryId.Music);

publicmusiclibrary = musiclibrary;

publicmusiclibrary.DefinitionChanged += Publicmusiclibrary_DefinitionChanged;

StorageLibrary pictureslibrary = await StorageLibrary.GetLibraryAsync(KnownLibraryId.Pictures);

publicpictureslibrary = pictureslibrary;

publicpictureslibrary.DefinitionChanged += Publicpictureslibrary_DefinitionChanged;

}

private async void Publicpictureslibrary_DefinitionChanged(StorageLibrary sender, object args)
{
activelibrary = sender;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach (IStorageItem itm in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(itm.Name);
}
}

private async void Publicmusiclibrary_DefinitionChanged(StorageLibrary sender, object args)
{
activelibrary = sender;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach(IStorageItem itm in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(itm.Name);
}
}

private async void Publicvideoslibrary_DefinitionChanged(StorageLibrary sender, object args)
{
activelibrary = sender;

mainfolder = activelibrary.SaveFolder;

items_listbox.Items.Clear();

foreach (IStorageItem itm in await mainfolder.GetItemsAsync())
{
items_listbox.Items.Add(itm.Name);
}
}
}
}
the problem is in the underlining text

it says object reference not set to an instance object and its really weird!!!:)

it is an almost-completed storage for pictures,videos and music libraries.

and it cant load the items within the mainfolder!:)

AndyAinscow

You have this line of code
IStorageFolder mainfolder = null;
But I don't see anywhere where you actually assign a value to mainfolder.

In your DoubleTapped handler the faulting line
item = await mainfolder.GetItemAsync(itm.Content.ToString());
will fail with your error message if mainfolder is null.

Max Destiny

ASKER

what!?

Mainfolder is assigned from the beginning.The problem aint there.Anyway im gonna add a new listviewitem so...

Max Destiny

ASKER

have you read all the lines?

AndyAinscow

Yes I have and I have searched through your code. You declare a variable called mainfolder and assign the value null to it.
Where do you actually assign a real value to it?

object reference not set to an instance object That error message is when you have something with a value null and attempt to use it eg. null.GetItemAsync

Max Destiny

ASKER

I just did it

Max Destiny

ASKER

mainfolder may be null at beginning but when you select items by the listbox it becomes non-nullable

ASKER CERTIFIED SOLUTION

AndyAinscow

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