UWP中的消息提示框(一)

不管什麼平臺，應用內難免會出現一些消息提示框，下麵就來聊聊我在UWP里用到的消息提示框。

彈窗也可按是否需要用戶操作促發一些邏輯進行分為兩大類。

  不需要用戶干涉的一類：

  MessageDialog：操作簡單，寫起來也省事，想具體瞭解的請參考MSDN 先看看效果

   PC上效果：

  mobile上效果：

  再看看代碼(●'◡'●)

    前臺：

   <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" >
        <RelativePanel  HorizontalAlignment="Center">
            <TextBlock x:Name="tbHW" Text="Hello 彈窗"  />
            <TextBlock x:Name="tb" RelativePanel.Below="tbHW" Margin="0,10" FontSize="20" Foreground="#f90"/>
        </RelativePanel>
        <StackPanel VerticalAlignment="Bottom" Orientation="Horizontal">
            <Button Content="MessageDialog" Click="Button_Click"/>
        </StackPanel>
    </Grid>

  後臺：

 private void Button_Click(object sender, RoutedEventArgs e)
        {
            this.tb.Text = "";
            Button btn = sender as Button;
            switch (btn.Content.ToString())
            {
                case "MessageDialog":
                    ShowMessageDialog();
                    break;
            }
        }

        private async void ShowMessageDialog()
        {
            var msgDialog = new Windows.UI.Popups.MessageDialog("我是一個提示內容") { Title = "提示標題" };
            msgDialog.Commands.Add(new Windows.UI.Popups.UICommand("確定", uiCommand => { this.tb.Text = $"您點擊了：{uiCommand.Label}"; }));
            msgDialog.Commands.Add(new Windows.UI.Popups.UICommand("取消", uiCommand => { this.tb.Text = $"您點擊了：{uiCommand.Label}"; }));
            await msgDialog.ShowAsync();
        }

       很簡單，但是不能控制顯示位置、字體顏色、大小等，實際應用中醬紫的界面也很難說服UI妹紙。。。不要方，辦法還是很多滴，下麵再來介紹另外一種實現:通過Popup+UserControl來實現自己消息提示框。

    還是先看效果吧。

繼續來看代碼：

新建一個用戶控制項，暫叫它MessagePopupWindow吧。

MessagePopupWindow.xaml

 <Grid>
        <Border x:Name="OutBorder" Background="#55000000" 
                VerticalAlignment="Stretch" 
                HorizontalAlignment="Stretch"/>

        <StackPanel x:Name="ContentGrid" Background="White" 
              Margin="45,45"
              Orientation="Vertical"
              VerticalAlignment="Center">

            <Grid Padding="20">
                <TextBlock x:Name="tbContent"
                           Grid.Row="0" 
                           TextWrapping="Wrap"  
                           HorizontalAlignment="Center" />
            </Grid>

            <Grid Padding="15">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="15"/>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <Button Grid.Column="0" x:Name="btnLeft" 
                        Content="確定" 
                        HorizontalAlignment="Stretch"
                        HorizontalContentAlignment="Center"
                        VerticalAlignment="Center"
                        VerticalContentAlignment="Center"
                        BorderThickness="0" 
                        Click="LeftButton_Click"
                        Background="#f90"
                        Foreground="White"
                        MaxWidth="150"/>
                <Button 
                    Grid.Column="2" 
                    x:Name="btnRight" 
                    Content="取消" 
                    Click="RightButton_Click"
                    HorizontalAlignment="Stretch"
                    HorizontalContentAlignment="Center"
                    VerticalAlignment="Center"  
                    VerticalContentAlignment="Center"
                    BorderThickness="0"
                    Background="Gray"
                    Foreground="BlanchedAlmond"
                    MaxWidth="150"/>
            </Grid>
        </StackPanel>
    </Grid>

MessagePopupWindow.xaml.cs

 public sealed partial class MessagePopupWindow : UserControl
    {
        private Popup m_Popup;
        private string m_TextBlockContent;
        private MessagePopupWindow()
        {
            this.InitializeComponent();

            m_Popup = new Popup();
            this.Width = Window.Current.Bounds.Width;
            this.Height = Window.Current.Bounds.Height;
            m_Popup.Child = this;
            this.Loaded += MessagePopupWindow_Loaded;
            this.Unloaded += MessagePopupWindow_Unloaded;
        }


        public MessagePopupWindow(string showMsg) : this()
        {
            this.m_TextBlockContent = showMsg;
        }
        private void MessagePopupWindow_Loaded(object sender, RoutedEventArgs e)
        {
            this.tbContent.Text = m_TextBlockContent;
            Window.Current.SizeChanged += MessagePopupWindow_SizeChanged; ;
        }

        private void MessagePopupWindow_SizeChanged(object sender, Windows.UI.Core.WindowSizeChangedEventArgs e)
        {
            this.Width = e.Size.Width;
            this.Height = e.Size.Height;
        }

        private void MessagePopupWindow_Unloaded(object sender, RoutedEventArgs e)
        {
            Window.Current.SizeChanged -= MessagePopupWindow_SizeChanged; ;
        }


        public void ShowWIndow()
        {
            m_Popup.IsOpen = true;
        }

        private void DismissWindow()
        {
            m_Popup.IsOpen = false;
        }

        private void LeftButton_Click(object sender, RoutedEventArgs e)
        {
            DismissWindow();
            LeftClick?.Invoke(this, e);
        }

        private void RightButton_Click(object sender, RoutedEventArgs e)
        {
            DismissWindow();
            RightClick?.Invoke(this, e);
        }

        public event EventHandler<RoutedEventArgs> LeftClick;
        public event EventHandler<RoutedEventArgs> RightClick;
    }

MainPage.xaml改動如下:

MainPage.xaml.cs在Button_Click里增加一個case來處理點擊“Custom”按鈕的點擊事件,

case "Custom":
                    ShowMessagePopupWindow();
                    break;

ShowMessagePopupWindow方法主要如下：

 private void ShowMessagePopupWindow()
        {
            var msgPopup = new Controls.MessagePopupWindow("我是一個提示內容");
            msgPopup.LeftClick += (s, e) => { this.tb.Text = "您點擊了：確定"; };
            msgPopup.RightClick += (s, e) => { this.tb.Text = "您點擊了：取消"; };
            msgPopup.ShowWIndow();
        }

這樣，一個自定義的消息提示框就完成了。。。

還有另一種不需要用戶干預自己消失的提示框我們下期再約。

謝謝觀賞！