070-506 全真模擬試験 DEMO

問題9: }
You attempt to run the application. You receive the following error message:
"Invalid crossthread access."
You need to ensure that worker executes successfully.
What should you do?
A. Replace line 11 with the following code segment.
var b = (bool )checkBox.GetValue(CheckBox.IsCheckedProperty)
bool isChecked = b.HasValue && b.Value
B. Replace line 11 with the following code segment.
bool isChecked = false
Dispatcher.BeginInvoke(() =>
{
isChecked = checkBox.IsChecked.HasValue && checkBox.IsChecked.Value
})
C. Replace line 18 with the following code segment.
statusTextBlock.SetValue(TextBlock.TextProperty, e.ProgressPercentage + "%")
D. Replace line 18 with the following code segment.
Dispatcher.BeginInvoke(() =>
{
statusTextBlock.Text = e.ProgressPercentage + "%"
})
正解: B
13.You are developing an application by using Silverlight 4 and Microsoft.NET Framework 4.
You add the following code segment. (Line numbers are included for reference only.)
01 public class MyControl : Control
02 {
03
04 public string Title
05 {
06 get { return (string)GetValue(TitleProperty)
}
07 set { SetValue(TitleProperty, value)
}
08 }
09 }
You need to create a dependency property named TitleProperty that allows developers to set the Title.
You also need to ensure that the default value of the TitleProperty dependency property is set to Untitled.
Which code segment you add at line 03?
A. public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Untitled",
typeof(string),
typeof(MyControl),
null)
B. public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Untitled",
typeof(string),
typeof(MyControl),
new PropertyMetadata("Title"))
C. public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Title",
typeof(string),
typeof(MyControl),
new PropertyMetadata("Untitled"))
D. public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Title",
typeof(string),
typeof(MyControl),
new PropertyMetadata(new PropertyChangedCallback((depObj, args) =>
{
depObj.SetValue(MyControl.TitleProperty, "Untitled")
})))
正解: C
14.You are developing an application by using Silverlight 4 and Microsoft.NET Framework 4.
You create a control named MyControl in the application. Each instance of the control contains a list of
FrameworkElement objects.
You add the following code segment. (Line numbers are included for reference only.)
01 public class MyControl : Control
02 {
03
04 public List<FrameworkElement> ChildElements
05 {
06 get {
07 return List<FrameworkElement>)GetValue(MyControl.ChildElementsProperty)
08 }
09 }
10
11 public MyControl()
12 {
13
14 }
15 static MyControl()
16 {
17
18 }
19 }
You need to create the ChildElementsProperty dependency property. You also need to initialize the
property by using an empty list of FrameworkElement objects.
Which two actions should you perform? (Each correct answer presents part of the solution. Choose two.)
A. Add the following code segment at line 03.
public static readonly DependencyProperty ChildElementsProperty =
DependencyProperty.Register("ChildElements", typeof(List<FrameworkElement>), typeof(MyControl),
new PropertyMetadata(new List<FrameworkElement>()))
B. Add the following code segment at line 03.
public static readonly DependencyProperty ChildElementsProperty =
DependencyProperty.Register("ChildElements", typeof(List<FrameworkElement>), typeof(MyControl),
new PropertyMetadata(null))
C. Add the following code segment at line 13.
SetValue(MyControl.ChildElementsProperty, new List<FrameworkElement>())
D. Add the following code segment at line 17.
ChildElementsProperty =
DependencyProperty.Register("ChildElements", typeof(List<FrameworkElement>), typeof(MyControl),
new PropertyMetadata(new List<FrameworkElement>()))
正解: B, C
15.You are developing an application by using Silverlight 4 and Microsoft.NET Framework 4.
You add the following code segment. (Line numbers are included for reference only.)
01 var outerCanvas = new Canvas()
02 var innerCanvas = new Canvas()
03 innerCanvas.Width = 200
04 innerCanvas.Height = 200
05 outerCanvas.Children.Add(innerCanvas)
06
You need to set the distance between the left of the innerCanvas element and the left of the outerCanvas
element to 150 pixels.
Which code segment should you add at line 06?
A. outerCanvas.Margin = new Thickness(0.0, 150.0, 0.0, 0.0)
B. innerCanvas.Margin = new Thickness(0.0, 150.0, 0.0, 0.0)
C. outerCanvas.SetValue(Canvas.LeftProperty, 150.0)
D. innerCanvas.SetValue(Canvas.LeftProperty, 150.0)
正解: D
16.You are developing a Silverlight 4 application. The application contains a Product class that has a
public Boolean property named IsAvailable.
You need to create a value converter that binds data to the Visibility property of a Button control.
Which code segment should you use?
A. public class BoolToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo
culture)
{
bool result = System.Convert.ToBoolean(parameter)
return result Visibility.Visible : Visibility.Collapsed
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException()
}
}
B. public class BoolToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo
culture)
{
bool result = System.Convert.ToBoolean(value)
return result Visibility.Visible : Visibility.Collapsed
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException()
}
}
C. public class BoolToVisibilityConverter : PropertyPathConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo
culture)
{
return this.ConvertTo(value, typeof(Visibility))
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException()
}
}
D. public class BoolToVisibilityConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo
culture)
{
bool result = System.Convert.ToBoolean(value)
return result Visibility. Visible : Visibility. Collapsed
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException()
}
}
正解: B
17.You are developing a Silverlight 4 application. The application contains a Product class that has a
public string property named Name.
You create a TextBox control by using the following XAML fragment.
<TextBox Text="{Binding Name, ValidatesOnDataErrors=True}" />
You need to ensure that validation errors are reported to the user interface. You also need to ensure that
a validation error will occur when the TextBox control is empty.
Which code segment should you use?
A. public class Product
{
[Required()]
public string Name { get
set
}
}
B. public class Product : IDataErrorInfo
{
public string Name { get
set
}
public string Error { get { return null
} }
public string this[string columnName]
{
get
{
if (columnName == "Name" && string.IsNullOrEmpty(Name))
{
throw new ValidationException("Name should not be empty!")
}
return string.Empty
}
}
}
C. public class Product : IDataErrorInfo
{
public string Name { get
set
}
public string Error { get { return null
} }
public string this[string columnName]
{
get
{
if (columnName == "Name" && string.IsNullOrEmpty(Name))
{
return "Name should not be empty!"
}
return string.Empty
}
}
}
D. public class Product
{
private string _name
public string Name
{
get { return _name
}
set
{
if (string.IsNullOrEmpty(value))
throw new ValidationException("Name should not be empty!")
_name = value
}
}
}
正解: C
18.You are developing a ticketing application by using Silverlight 4. You have a listbox named lstTickets
that contains a list of the tickets. The page contains a button that allows the user to print the tickets. The
PrintView UserControl binds to the type in lstTickets and is designed to fit a standard sheet of paper.
You add the following code segment to the button event handler. (Line numbers are included for
reference only.)
01 var doc = new PrintDocument()
02 var view = new PrintView()
03 doc.PrintPage += (s, args) =>
04 {
05 var ppc = doc.PrintedPageCount
06 if (ppc < lstTickets.Items.Count)
07 {
08 var data = lstTickets.Items[ppc]
09 view.DataContext = data
10 args.PageVisual = view
11
12
13 }
14 }
15 doc.Print("tickets")
You need to use the Silverlight printing API to print each ticket on its own page. You also need to ensure
that all tickets in the listbox are printed.
Which code segment should you insert at lines 11 and 12?
A. if (args.HasMorePages == false)
return
B. if (args.HasMorePages == true)
return
C. if (doc.PrintedPageCount < this.lstTickets.Items.Count 1)
args.HasMorePages = true
D. if (ppc == this.lstTickets.Items.Count 1)
doc.EndPrint += (o, p) => { return
}
正解: C
19.You are developing an outofbrowser
application by using Silverlight 4.
The main page of the application contains the following code segment.
public MainPage()
{
InitializeComponent()
NetworkChange.NetworkAddressChanged += (s, e) => CheckNetworkStatusAndRaiseToast()
CheckNetworkStatusAndRaiseToast()
}
You need to ensure that the application will raise a toast notification when network connectivity changes.
Which two actions should you perform in the CheckNetworkStatusAndRaiseToast method? (Each correct
answer presents part of the solution. Choose two.)
A. Verify that App.Current.IsRunningOutOfBrowser is true.
B. Verify that App.Current.IsRunningOutOfBrowser is false.
C. Verify that App.Current.HasElevatedPermissions is true.
D. Verify that App.Current.HasElevatedPermissions is false.
E. Examine NetworkInterface.GetIsNetworkAvailable().
F. Call App.Current.CheckAndDownloadUpdateAsync() in a try/catch block.
正解: A, E