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VisualStateManager.GoToElementState(FrameworkElement, String, Boolean) Metodo

Definizione

Esegue la transizione dell'elemento tra due stati. Utilizzare questo metodo per eseguire la transizione degli stati definiti da un'applicazione, anziché da un controllo.

public:
 static bool GoToElementState(System::Windows::FrameworkElement ^ stateGroupsRoot, System::String ^ stateName, bool useTransitions);
public static bool GoToElementState (System.Windows.FrameworkElement stateGroupsRoot, string stateName, bool useTransitions);
static member GoToElementState : System.Windows.FrameworkElement * string * bool -> bool
Public Shared Function GoToElementState (stateGroupsRoot As FrameworkElement, stateName As String, useTransitions As Boolean) As Boolean

Parametri

stateGroupsRoot
FrameworkElement

Elemento radice che contiene l'oggetto VisualStateManager.

stateName
String

Stato finale della transizione.

useTransitions
Boolean

true per utilizzare un oggetto VisualTransition per eseguire la transizione tra stati; in caso contrario, false.

Restituisce

Boolean

true se il controllo ha eseguito correttamente la transizione al nuovo stato. In caso contrario, false.

Eccezioni

stateGroupsRoot è null.

-oppure- stateName è null.

Esempio

Nell'esempio seguente viene creata un'applicazione che richiede all'utente di indovinare un numero compreso tra 1 e 100. Quando l'utente immette un numero, l'applicazione indica se l'ipotesi è troppo elevata, troppo bassa o corretta. Il codice XAML seguente crea l'interfaccia utente per l'applicazione e definisce 4 stati: TooLow, TooHigh, Correcte Guessing. All'avvio dell'applicazione, si trova nello Guessing stato . .

<Grid x:Name="LayoutRoot">
  <Grid.Background>
    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
      <GradientStop Color="#FF022343" Offset="0"/>
      <GradientStop Color="#FF006BD2" Offset="1"/>
    </LinearGradientBrush>
  </Grid.Background>
  <VisualStateManager.VisualStateGroups>
    <VisualStateGroup x:Name="ResultStates">
      <VisualStateGroup.Transitions>
        <VisualTransition GeneratedDuration="0:0:0.5">
          <VisualTransition.GeneratedEasingFunction>
            <CubicEase EasingMode="EaseOut"/>
          </VisualTransition.GeneratedEasingFunction>
        </VisualTransition>
      </VisualStateGroup.Transitions>
      <VisualState x:Name="TooLow">
        <Storyboard>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[1].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FFD22700"/>
          </ColorAnimationUsingKeyFrames>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[0].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FFE2D7D0"/>
          </ColorAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleX)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleY)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[0].(GradientStop.Offset)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingDoubleKeyFrame KeyTime="0" Value="0.5"/>
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </VisualState>
      <VisualState x:Name="TooHigh">
        <Storyboard>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[1].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FFF3EBE9"/>
          </ColorAnimationUsingKeyFrames>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[0].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FFF12807"/>
          </ColorAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleX)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleY)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[1].(GradientStop.Offset)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingDoubleKeyFrame KeyTime="0" Value="0.5"/>
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </VisualState>
      <VisualState x:Name="Correct">
        <Storyboard>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[0].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FF0E4302"/>
          </ColorAnimationUsingKeyFrames>
          <ColorAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(Panel.Background).
              (GradientBrush.GradientStops)[1].(GradientStop.Color)" 
            Storyboard.TargetName="LayoutRoot">
            <EasingColorKeyFrame KeyTime="0" Value="#FF14D200"/>
          </ColorAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleX)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetProperty="(UIElement.RenderTransform).
              (TransformGroup.Children)[0].(ScaleTransform.ScaleY)" 
            Storyboard.TargetName="viewbox">
            <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </VisualState>
      <VisualState x:Name="Guessing"/>
    </VisualStateGroup>
  </VisualStateManager.VisualStateGroups>
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto"/>
    <RowDefinition Height="Auto"/>
    <RowDefinition/>
  </Grid.RowDefinitions>
  <Grid.ColumnDefinitions>
    <ColumnDefinition/>
    <ColumnDefinition Width="247"/>
  </Grid.ColumnDefinitions>
  <TextBlock Grid.Row="0" Grid.ColumnSpan="2" Margin="20,5,20,5" 
             FontSize="24" Foreground="White"
             Text="Guess a number between 1 and 100"/>
  <TextBox x:Name="Guess" Grid.Row="1" Margin="20,20,10,10" 
           TextWrapping="Wrap" FontSize="48" 
           TextChanged="OnTypingGuess"/>
  <Button x:Name="GuessButton" Grid.Row="1" Content="Guess" 
          Margin="10,20,20,10" Grid.Column="1" 
          FontSize="48" Click="OnGuess" 
          IsDefault="True"/>
  <Viewbox x:Name="viewbox" Grid.ColumnSpan="2" Grid.Row="2"
           Margin="20,10,20,20" RenderTransformOrigin="0.5,0.5">
    <Viewbox.RenderTransform>
      <TransformGroup>
        <ScaleTransform ScaleX="0" ScaleY="0"/>
        <SkewTransform/>
        <RotateTransform/>
        <TranslateTransform/>
      </TransformGroup>
    </Viewbox.RenderTransform>
    <TextBlock x:Name="Result" TextWrapping="Wrap"/>
  </Viewbox>
</Grid>

Il codice seguente illustra la logica dell'applicazione. Quando l'utente immette un numero e fa clic sul pulsante, l'applicazione chiama GoToElementState per passare a TooHigh, TooLowo Correct per fornire commenti e suggerimenti all'utente sull'ipotesi. Per provare questo esempio, chiamare il GenerateNumber metodo all'inizio dell'applicazione.

int number;

private void GenerateNumber()
{
    System.Random r = new System.Random();
    number = r.Next(100) + 1;
}

private void OnGuess(object sender, System.Windows.RoutedEventArgs e)
{
    int guess;

    if (int.TryParse(this.Guess.Text, out guess))
    {
        if (guess < this.number)
        {
            VisualStateManager.GoToElementState(this.LayoutRoot, "TooLow", true);
            this.Result.Text = "Too Low!";
        }
        else if (guess > this.number)
        {
            VisualStateManager.GoToElementState(this.LayoutRoot, "TooHigh", true);
            this.Result.Text = "Too High!";
        }
        else
        {
            VisualStateManager.GoToElementState(this.LayoutRoot, "Correct", true);
            this.Result.Text = "Correct!";
        }
    }
}

private void OnTypingGuess(object sender, System.Windows.Controls.TextChangedEventArgs e)
{
    VisualStateManager.GoToElementState(this.LayoutRoot, "Guessing", true);
    this.Result.Text = "";
}
Private number As Integer

Private Sub GenerateNumber()
    Dim r As New System.Random()
    number = r.Next(100) + 1
End Sub

Private Sub OnGuess(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs)
    Dim guess As Integer

    If Integer.TryParse(Me.Guess.Text, guess) Then
        If guess < Me.number Then
            VisualStateManager.GoToElementState(Me.LayoutRoot, "TooLow", True)
            Me.Result.Text = "Too Low!"
        ElseIf guess > Me.number Then
            VisualStateManager.GoToElementState(Me.LayoutRoot, "TooHigh", True)
            Me.Result.Text = "Too High!"
        Else
            VisualStateManager.GoToElementState(Me.LayoutRoot, "Correct", True)
            Me.Result.Text = "Correct!"
        End If
    End If
End Sub

Private Sub OnTypingGuess(ByVal sender As Object, ByVal e As System.Windows.Controls.TextChangedEventArgs)
    VisualStateManager.GoToElementState(Me.LayoutRoot, "Guessing", True)
    Me.Result.Text = ""
End Sub

Commenti

Chiamare il GoToElementState metodo per modificare gli stati in un elemento all'esterno di un ControlTemplate oggetto , ad esempio se si usa un VisualStateManager oggetto in un DataTemplate oggetto o Window. Chiamare il GoToState metodo se si modificano gli stati in un controllo che usa in VisualStateManager .ControlTemplate

Si applica a