Getting Started with Windows 8 development (v) pop-up prompt box messagedialog with await, async keyword

In the previous Silverlight, WPF pop-up window prompts are displayed in the MessageBox class, now Windows 8 uses the Messagedialog class in the Windows.UI.Popups namespace instead of MessageBox.

The Messagedialog class has the following common methods and properties:

Showasync (): Asynchronous pop-up message box.

Commands: Add a command to synchronize the buttons on the pop-up screen.

Defaultcommandindex: Sets the index of the default button and presses the ENTER key to activate the command button for the index

Cancelcommandindex: Sets the index of the Cancel Exit button, and pressing ESC activates the corresponding command button for the index

Title: Caption of pop-up message box

Async: When used for method declarations, this keyword tells the compiler that there may be a await keyword in the method body.

Await: Analog synchronous wait for asynchronous operations, declaring asynchronous operations with this keyword waiting for the asynchronous operation to complete before continuing, but not blocking the UI thread.

Note: The method body using the AWAIT keyword must use the Async declaration method

Now we look at Messagedialog, async, await by an example:

<grid background= "{StaticResource Applicationpagebackgroundthemebrush}" > <button Content= " "Horizontalalignment=" left "margin=" 430,196,0,0 "verticalalignment=" "The Top" height= "Wuyi" Widt H= "114" click= "First_click"/> <button content= "secend Msg" horizontalalignment= "left" margin= "606,196,0,0" verticalalignment= "Top" height= "Wuyi" width= "114" click= "Secend_click"/> <button content= "Third Msg" horizontalalignment= "left" margin= "788,196,0,0" verticalalignment= "Top" Height
            = "Wuyi" width= "114" click= "Third_click"/> <button content= "Fourth MSG" horizontalalignment= "left" Margin= "975,196,0,0" verticalalignment= "Top" height= "WU" width= "114" click= "Fourth_click"/> & Lt
                   TextBlock horizontalalignment= "left" name= "Tbtext" margin= "573,160,0,0" textwrapping= "Wrap" Text= "TextbloCK "verticalalignment=" Top "height=" "width=" 565 "fontsize="/> </Grid> 

One: The simplest of messagedialog

Private async void First_click (Object 

sender, RoutedEventArgs e)   
{   
    messagedialog msg = new Messagedialog (" Hello world! This is the first hint. ");   
    Msg. Title = "Hint 1";   
    var msginfo = await Msg. Showasync ();   
}

Two: custom Command set message box

Private async void Secend_click (object sender, 

RoutedEventArgs e)   
        {   
            Messagedialog msg1 = new Messagedialog ("Hello world! This is the second hint.");   
            Msg1. Title = "Hint 2";   
            MSG1.COMMANDS.ADD ("OK", command =>   
            {   
                this.tbText.Text = "You clicked the OK button, the second set of prompts";   
            });   
            MSG1.COMMANDS.ADD (The New Uicommand ("Cancel", command =>   
            {   
                this.tbText.Text = "You clicked the Cancel button, the second set of prompts";   
            }));   
            var msg1info = await msg1. Showasync ();   
        }

Three: Using await analog synchronization to get the code snippet that is currently running the response using the command ID

Private 

async void Third_click (object sender, RoutedEventArgs e)   
        {   
            Messagedialog msg1 = new Messagedialog (" Hello world! This is the third hint. ");   
            Msg1. Title = "Hint 3";   
            MSG1.COMMANDS.ADD (New Uicommand ("OK", NULL, 0));   
            MSG1.COMMANDS.ADD (New Uicommand ("Cancel", NULL, 1));   
            Msg1. Defaultcommandindex = 0;   
            Msg1. Cancelcommandindex = 1;   
            var msg1info = await msg1. Showasync ();   
            Switch (Convert.ToInt32 (msg1info). Id)   
            {case    
                0:   
                     this.tbText.Text = "You clicked the OK button, the third set of prompts";   
                Case 1:   
                    this.tbText.Text = "You clicked the Cancel button, the third set of prompts";   
                Default: Break   
                    ;   
            }   
        }