我想要一個按鈕來更改標簽的可見性，一旦我單擊它。xaml視圖：<local:ButtonRenderer Text="Connect" BackgroundColor="#6DCFF6" TextColor="White" Command="{Binding viewTemperature}" CornerRadius="10" WidthRequest="200" IsVisible="{Binding !isConnecting}"/><Label Text="PlaceholderText" TextDecorations="Underline" TextColor="White" Margin="0,5,0,0" HorizontalTextAlignment="Center" IsVisible="{Binding !isConnecting}"/>視圖模型viewTemperature = new Command(async () =>{ isConnecting = true; await _navigation.PushModalAsync(new TemperaturePage());}) ;public bool isConnecting{ get { return _isConnecting; } set { _isConnecting = value; PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(_isConnecting.ToString())); }}我已經在代碼中放置了斷點，并且 isConnected 在我的視圖模型中被更改為 true。但是，我的標簽的可見性沒有改變。我懷疑這PropertyChanged不應該改變布爾值？
2 回答
滄海一幻覺
TA貢獻1824條經驗 獲得超5個贊
你不能這樣做IsVisible="{Binding !isConnecting}"，這是行不通的。
您可以制作 InvertBoolConverter，或者更簡單的選項是使用觸發器。這是一個示例：
<Label Text="PlaceholderText" TextDecorations="Underline" TextColor="White" Margin="0,5,0,0" HorizontalTextAlignment="Center"
IsVisible="{Binding isConnecting}">
<Label.Triggers>
<DataTrigger TargetType="Label" Binding="{Binding isConnecting}" Value="True">
<Setter Property="IsVisible" Value="False" />
</DataTrigger>
<DataTrigger TargetType="Label" Binding="{Binding isConnecting}" Value="False">
<Setter Property="IsVisible" Value="True" />
</DataTrigger>
</Label.Triggers>
</Label>
BIG陽
TA貢獻1859條經驗 獲得超6個贊
您可以改進您的代碼ViewModel
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
private bool isconnecting ;
public bool isConnecting
{
get
{
return isconnecting;
}
set
{
if (isconnecting != value)
{
isconnecting = value;
NotifyPropertyChanged();
}
}
}
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