Task List

Create a Task List application with this Tutorial for Listbox-based To Do lists with Open/Save support using LINQ to XML plus Add/Remove Items.

www.cespage.com/silverlight/sl4tut5.html

Step 1

Start Microsoft Visual Web Developer 2010 Express, then Select File then New Project... Select "Visual Basic" then "Silverlight Application" from Templates, select a Location if you wish, then enter a name for the Project and then click OK, see below:

Step 2

New Silverlight Application window should appear, uncheck the box "Host the Silverlight Application in a new Web site" and then select the required Silverlight Version, see below:

Step 3

A Blank Page named MainPage.xaml should then appear, see below:

Step 4

Select Project then Add Reference... The "Add Reference" window should appear, select "System.XML.Linq" from the ".NET" List, see below:

Step 5

Add the Reference to "System.XML.Linq" by Clicking on OK
Then from the All Silverlight Controls section in the Toolbox select the Canvas control:

Step 6

Draw a Canvas on the Page then in the XAML Pane above the "</Grid>" then change the "Canvas1" line to the following:

<Canvas Height="65" Width="400" VerticalAlignment="Top" HorizontalAlignment="Left" Name="Toolbar"></Canvas>

See below:

Step 7

Then from the Common Silverlight Controls section in the Toolbox select the Button control:

Step 8

Draw Five Buttons on the Canvas (Toolbar) by dragging the Buttons from the Toolbox onto the Canvas or in the XAML Pane inbetween the "<Canvas>" and "</Canvas>" tags type the following:

<Button Canvas.Left="6" Canvas.Top="6" Height="23" Width="75" Name="Button1" Content="Button"/> 
<Button Canvas.Left="87" Canvas.Top="6" Height="23" Width="75" Name="Button2" Content="Button"/> 
<Button Canvas.Left="168" Canvas.Top="6" Height="23" Width="75" Name="Button3" Content="Button"/> 
<Button Canvas.Left="249" Canvas.Top="6" Height="23" Width="75" Name="Button4" Content="Button"/> 
<Button Canvas.Left="249" Canvas.Top="35" Height="23" Width="75" Name="Button5" Content="Button"/> 

See below:

Step 9

Click on the first Button (Button1), then goto the Properties box and change the Name to "New" and the Content property from Button to "New" (both without the quotes), see below:

Step 10

Click on the second Button (Button2), then goto the Properties box and change the Name to "Open" and the Content property from Button to "Open...".
Then click on the third Button (Button3) and goto the Properties box and change then Name to "Save" and the Content property from Button to "Save...".
Click on the fourth button (Button4) and then change the Name to "Remove" in the Properties box and the Content property to "Remove".
Then click on the fifth button (Button5) and in the Properties box change the name to "Add" and the Content property to "Add" (all without the quotes), the page should appear as below:

Step 11

Then from the Common Silverlight Controls section in the Toolbox select the TextBox control:

Step 12

Draw a TextBox on the Canvas (Toolbar) with the Buttons, and in the XAML Pane below the "<Button>" tag and above the "</Canvas>" change "TextBox1" to the following:

<TextBox Canvas.Left="6" Canvas.Top="36" Height="23" Width="237" Name="Subject"/> 

See below:

Step 13

Then from the Common Silverlight Controls section in the Toolbox select the ListBox control:

Step 14

Draw a ListBox on the Page, below the Canvas with the Buttons, and in the XAML Pane above the "</Grid>" and below the "</Canvas>" change "ListBox1" to the following:

<ListBox Height="235" Width="400" Margin="0,65,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Name="Tasks"/>

See below:

Step 15

Right Click on the Page or the entry for "MainPage.xaml" in Solution Explorer and choose the "View Code" option. In the Code View above the "Partial Public Class MainPage" line type the following:

Imports System.Xml.Linq

See Below:

Step 16

Return to the Designer View, by selecting the "MainPage.xaml" Tab, or Right Click on the Page or the Entry for "MainPage.xaml" in Solution Explorer and choose the "View Designer" option.
Double Click on the "New" Button Control and type in the New_Click Sub:

If MessageBox.Show("Start a New Task List?", "Task List", _
  MessageBoxButton.OKCancel) = MessageBoxResult.OK Then
  Subject.Text = ""
  Tasks.Items.Clear()
End If

See Below:

Step 17

Return to the Designer View, by selecting the "MainPage.xaml" Tab, or Right Click on the Page or the Entry for "MainPage.xaml" in Solution Explorer and choose the "View Designer" option.
Double Click on the "Open..." Button and type in the Open_Click Sub:

Dim OpenDialog As New OpenFileDialog
Dim _xml As XElement
OpenDialog.Filter = "Task List Files (*.tsk)|*.tsk"
If OpenDialog.ShowDialog Then
  Try
    If OpenDialog.File.Exists Then
      _xml = XElement.Parse(OpenDialog.File.OpenText.ReadToEnd)
      If _xml.Name.LocalName = "tasklist" Then ' Root
        Tasks.Items.Clear()
        For Each _Task As XElement In _xml.Descendants("task")
          Dim _item As New CheckBox
          _item.IsChecked = _Task.FirstAttribute.Value.ToLower = "checked"
          _item.Content = _Task.Value
          Tasks.Items.Add(_item)
      Next
    End If
  End If
  Catch ex As Exception
    ' Ignore Errors
  End Try
End If

See Below:

Step 18

Return to the Designer View again, by selecting the "MainPage.xaml" Tab, or Right Click on the Page or the Entry for "MainPage.xaml" in Solution Explorer and choose the "View Designer" option.
Double Click on the "Save..." Button and type in the Save_Click Sub:

Dim SaveDialog As New SaveFileDialog
Dim _doc As XDocument
SaveDialog.Filter = "Task List Files (*.tsk)|*.tsk"
If SaveDialog.ShowDialog Then
  Try
    Dim _items As New XElement("tasklist")
    For Each _Task As CheckBox In Tasks.Items
      _items.Add(New XElement("task", _Task.Content, _
      New XAttribute("value", IIf(_Task.IsChecked, _
      "checked", "unchecked"))))
    Next
    _doc = New XDocument(New XDeclaration("1.0", "utf-8", "yes"), _items)
  Using FileStream As IO.StreamWriter = New IO.StreamWriter(SaveDialog.OpenFile)
    _doc.Save(FileStream)
  End Using
  Catch ex As Exception
    ' Ignore Errors
  End Try
End If

See Below:

Step 19

Return to the Designer View, by selecting the "MainPage.xaml" Tab, or Right Click on the Page or the Entry for "MainPage.xaml" in Solution Explorer and choose the "View Designer" option.
Double Click on the "Remove" Button Control and type in the Remove_Click Sub:

If Tasks.SelectedIndex > -1 Then ' Item Selected
  Tasks.Items.RemoveAt(Tasks.SelectedIndex) ' Remove Selected
End If

See Below:

Step 20

Return to the Designer View, by selecting the "MainPage.xaml" Tab, or Right Click on the Page or the Entry for "MainPage.xaml" in Solution Explorer and choose the "View Designer" option.
Double Click on the "Add" Button Control and type in the Add_Click Sub:

If Subject.Text <> "" Then ' Has Subject
  Dim _item As New CheckBox
  _item.Content = Subject.Text
  If Tasks.SelectedIndex > -1 Then ' Item Selected
    Tasks.Items.Insert(Tasks.SelectedIndex, _item) ' Insert before Selected
  Else
    Tasks.Items.Add(_item) ' Add to List End
  End If
End If

See Below:

Step 21

Save the Project as you have now finished the Silverlight application. Select Debug then Start Debugging or click on Start Debugging:

After you do, the following will appear in a new Web Browser window:

Step 22

Now type into the TextBox the Subject of a Task, then Click on the Add button to add some Tasks to, you can then "Save" this list to "Open" later, see below:

Step 23

Close the Browser window by clicking on the Close Button on the top right of the Web Browser to Stop the application.

This is a Simple Task List application with the ability to Open and Save Task Lists files as XML including the items checked and the order they appear. Try adding new features like being able to move items Up and Down the list and being able to Edit previously entered Tasks or use this as a basis for more complex XML-based applications!