Storage (S3)

The Amazon Simple Storage Service (Amazon S3) is a storage service that allows you to upload any kind of data at any time, from anywhere. This article will demonstrate how one can use this service from a WPF application and manage the uploaded files.

Step 1: Create the WPF Application

Create a standard WPF application and add 3 RadButtons and a RadListBox to it. The first button will list all of the files uploaded in our storage. The second button will upload a file and the third one will delete the selected file in the RadListBox.

Example 1: Defining the view

<Grid> 
    <Grid.ColumnDefinitions> 
        <ColumnDefinition Width="250" /> 
        <ColumnDefinition /> 
    </Grid.ColumnDefinitions> 
 
    <telerik:RadListBox x:Name="radListBox" ItemsSource="{Binding FileNames}" SelectedItem="{Binding SelectedItem, Mode=TwoWay}" /> 
 
    <Grid Grid.Column="1"> 
        <Grid.RowDefinitions> 
            <RowDefinition Height="Auto" /> 
            <RowDefinition Height="Auto"/> 
            <RowDefinition Height="Auto"/> 
        </Grid.RowDefinitions> 
 
        <telerik:RadButton Command="{Binding ListItemsCommand}"  Content="List Items"/> 
        <telerik:RadButton Command="{Binding UploadItemCommand}" Content="Upload Item" Grid.Row="1"/> 
        <telerik:RadButton Command="{Binding DeleteItemCommand}" Content="Delete item" Grid.Row="2"/> 
    </Grid> 
</Grid> 

Step 2: Install the NuGet package

Open the NuGet Package Manager and install the AWSSDK.S3 package.

aws-storage-nuget

In addition you need to add the following to your App.config file:

Example 2: Adding the AWS Profile in App.config

<?xml version="1.0" encoding="utf-8" ?> 
    <configuration> 
        <appSettings> 
            <add key="AWSProfileName" value="Telerik"/> 
            <add key="AWSRegion" value="eu-west-3" /> 
        </appSettings> 
    </configuration> 

If you do not have an AWS account in Visual Studio, please check the Getting Started article.

Step 3: Create a new bucket

Before proceeding with the example you will have to create a new bucket using the AWS Management Console. You can learn how to do that in the Creating a Bucket article.

Step 4: Define the ViewModel

The next step is to create the ViewModel. It will need an IAmazonS3 client object which will be used for managing the data. We also need to implement all of the commands that the RadButtons are bound to.

Example 3: Defining the ViewModel

public class ViewModel 
{ 
    string bucketName = "mytestbucket"; 
    IAmazonS3 client; 
 
    private object selectedItem; 
    private ObservableCollection<string> fileNames; 
    private IFileDialogService fileDialogService; 
 
    public ViewModel(IFileDialogService fileDialogService) 
    { 
        this.fileNames = new ObservableCollection<string>(); 
        this.ListItemsCommand = new DelegateCommand(OnListItems); 
        this.UploadItemCommand = new DelegateCommand(OnUploadItem); 
        this.DeleteItemCommand = new DelegateCommand(OnDeleteItem); 
        this.fileDialogService = fileDialogService; 
        this.client = new AmazonS3Client(); 
    } 
 
    public object SelectedItem 
    { 
        get { return this.selectedItem; } 
        set { this.selectedItem = value; } 
    } 
 
    public ObservableCollection<string> FileNames 
    { 
        get { return this.fileNames; } 
        set { this.fileNames = value; } 
    } 
 
    private ICommand listItemsCommand; 
 
    public ICommand ListItemsCommand 
    { 
        get { return this.listItemsCommand; } 
        set { this.listItemsCommand = value; } 
    } 
 
    private ICommand deleteItemCommand; 
 
    public ICommand DeleteItemCommand 
    { 
        get { return this.deleteItemCommand; } 
        set { this.deleteItemCommand = value; } 
    } 
 
    private ICommand uploadItemCommand; 
 
    public ICommand UploadItemCommand 
    { 
        get { return this.uploadItemCommand; } 
        set { this.uploadItemCommand = value; } 
    } 
 
    private void OnDeleteItem(object obj) 
    { 
        if (this.SelectedItem == null) 
        { 
            MessageBox.Show("Please select an Item"); 
            return; 
        } 
 
        string keyName = this.SelectedItem.ToString(); 
        DeleteObjectRequest request = new DeleteObjectRequest() 
        { 
            BucketName = bucketName, 
            Key = keyName 
        }; 
 
        var response = client.DeleteObject(request); 
    } 
 
    private void OnUploadItem(object obj) 
    { 
        var fileName = fileDialogService.OpenFileDialog(); 
        PutObjectRequest request = new PutObjectRequest() 
        { 
            BucketName = bucketName, 
            Key = fileName 
        }; 
 
        PutObjectResponse response = client.PutObject(request); 
    } 
 
    private void OnListItems(object obj) 
    { 
        var objects = client.ListObjects(bucketName); 
 
        this.FileNames.Clear(); 
 
        foreach (S3Object item in objects.S3Objects) 
        { 
            this.FileNames.Add(item.Key); 
        } 
    } 
} 
Public Class ViewModel 
    Private bucketName As String = "mytestbucket" 
 
    Private client As IAmazonS3 
 
    Private selectedItem As Object 
 
    Private fileNames As ObservableCollection(Of String) 
 
    Private fileDialogService As IFileDialogService 
 
    Public Sub New(ByVal fileDialogService As IFileDialogService) 
        Me.fileNames = New ObservableCollection(Of String)() 
        Me.ListItemsCommand = New DelegateCommand(AddressOf OnListItems) 
        Me.UploadItemCommand = New DelegateCommand(AddressOf OnUploadItem) 
        Me.DeleteItemCommand = New DelegateCommand(AddressOf OnDeleteItem) 
        Me.fileDialogService = fileDialogService 
        Me.client = New AmazonS3Client() 
    End Sub 
 
    Public Property SelectedItem As Object 
        Get 
            Return Me.selectedItem 
        End Get 
 
        Set(ByVal value As Object) 
            Me.selectedItem = value 
        End Set 
    End Property 
 
    Public Property FileNames As ObservableCollection(Of String) 
        Get 
            Return Me.fileNames 
        End Get 
 
        Set(ByVal value As ObservableCollection(Of String)) 
            Me.fileNames = value 
        End Set 
    End Property 
 
    Private listItemsCommand As ICommand 
 
    Public Property ListItemsCommand As ICommand 
        Get 
            Return Me.listItemsCommand 
        End Get 
 
        Set(ByVal value As ICommand) 
            Me.listItemsCommand = value 
        End Set 
    End Property 
 
    Private deleteItemCommand As ICommand 
 
    Public Property DeleteItemCommand As ICommand 
        Get 
            Return Me.deleteItemCommand 
        End Get 
 
        Set(ByVal value As ICommand) 
            Me.deleteItemCommand = value 
        End Set 
    End Property 
 
    Private uploadItemCommand As ICommand 
 
    Public Property UploadItemCommand As ICommand 
        Get 
            Return Me.uploadItemCommand 
        End Get 
 
        Set(ByVal value As ICommand) 
            Me.uploadItemCommand = value 
        End Set 
    End Property 
 
    Private Sub OnDeleteItem(ByVal obj As Object) 
        If Me.SelectedItem Is Nothing Then 
            MessageBox.Show("Please select an Item") 
            Return 
        End If 
 
        Dim keyName As String = Me.SelectedItem.ToString() 
        Dim request As DeleteObjectRequest = New DeleteObjectRequest() With {.BucketName = bucketName, .Key = keyName} 
        Dim response = client.DeleteObject(request) 
    End Sub 
 
    Private Sub OnUploadItem(ByVal obj As Object) 
        Dim fileName = fileDialogService.OpenFileDialog() 
        Dim request As PutObjectRequest = New PutObjectRequest() With {.BucketName = bucketName, .Key = fileName} 
        Dim response As PutObjectResponse = client.PutObject(request) 
    End Sub 
 
    Private Sub OnListItems(ByVal obj As Object) 
        Dim objects = client.ListObjects(bucketName) 
        Me.FileNames.Clear() 
        For Each item As S3Object In objects.S3Objects 
            Me.FileNames.Add(item.Key) 
        Next 
    End Sub 
End Class 

Step 5: Define the OpenFileDialogService

The only thing left is to define the interface through which we are opening the RadOpenFileDialog. We also need to define the implementation of that interface which will simply open a RadOpenFileDialog and return the path of the opened file.

Example 4: Defining the OpenFileDialogService and IFileDialogService

public interface IFileDialogService 
{ 
    string OpenFileDialog(); 
} 
 
public class OpenFileDialogService : IFileDialogService 
{ 
    public string OpenFileDialog() 
    { 
        RadOpenFileDialog choosefiledialog = new RadOpenFileDialog(); 
        choosefiledialog.Filter = "All Files (.)|."; 
        choosefiledialog.FilterIndex = 1; 
        choosefiledialog.Multiselect = false; 
        choosefiledialog.ShowDialog(); 
 
        if (choosefiledialog.DialogResult == true) 
        { 
            return choosefiledialog.FileName; 
        } 
 
        return string.Empty; 
    } 
} 
Interface IFileDialogService 
    Function OpenFileDialog() As String 
End Interface 
 
Public Class OpenFileDialogService 
Inherits IFileDialogService 
 
    Public Function OpenFileDialog() As String 
        Dim choosefiledialog As RadOpenFileDialog = New RadOpenFileDialog() 
        choosefiledialog.Filter = "All Files (.)|." 
        choosefiledialog.FilterIndex = 1 
        choosefiledialog.Multiselect = False 
        choosefiledialog.ShowDialog() 
        If choosefiledialog.DialogResult = True Then 
            Return choosefiledialog.FileName 
        End If 
 
        Return String.Empty 
    End Function 
End Class 

All that is left is to set the DataContext to our ViewModel and pass an instance of the OpenFileDialogService.

Example 5: Set the DataContext

public MainWindow() 
{ 
    InitializeComponent(); 
    this.DataContext = new ViewModel(new OpenFileDialogService()); 
} 
Public Sub MainWindow() 
    InitializeComponent() 
    Me.DataContext = New ViewModel(New OpenFileDialogService()) 
End Sub 

Figure 1: Example after uploading a file and listing it in the Office2016 theme

aws-storage-upload

See Also

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