C# 根据C中的条件隐藏/取消隐藏按钮#

我在Xamarin工作。在CredentialPage.xml页面中，有一个按钮，我想根据CredentialViewMode.cs页面中凭据的状态隐藏和取消隐藏该按钮

CredentialPage.xml

<Button x:Name="Button_Round"
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" />

要隐藏/取消隐藏按钮的条件

if(_credentialStatus == "Offered")
{
    // Button should be Visible
}
else
{
    // Hide the Button
}

---

使用IsVisible属性：

<Button x:Name="Button_Round"
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" 
IsVisible="{Binding IsOfferButtonVisible}"
/>

<Button x:Name="Button_Round"
IsVisible={Binding CredentialVisible}
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" />

---

使用IsVisible属性：

<Button x:Name="Button_Round"
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" 
IsVisible="{Binding IsOfferButtonVisible}"
/>

<Button x:Name="Button_Round"
IsVisible={Binding CredentialVisible}
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" />

---

将布尔属性添加到ViewModel中，例如：

private bool _credentialVisible;
public bool CredentialVisible
{
    get 
    {
        return _credentialVisible;
    }
    set
    {
       if (_credentialVisible != value)
       {
           _credentialVisible = value;
           NotifyPropertyChanged();
       }
    }
}

您的视图模型应该实现接口

INotifyPropertyChanged

：

public event PropertyChangedEventHandler PropertyChanged;

protected void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

然后在视图中绑定到

IsVisible

属性：

<Button x:Name="Button_Round"
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" 
IsVisible="{Binding IsOfferButtonVisible}"
/>

<Button x:Name="Button_Round"
IsVisible={Binding CredentialVisible}
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" />

然后您可以按如下方式使用它：

<ContentPage.Behaviors>
    <behaviors:EventHandlerBehavior EventName="Appearing">
        <behaviors:InvokeCommandAction Command="{Binding AppearingCommand}" />
    </behaviors:EventHandlerBehavior>
</ContentPage.Behaviors>

---

将布尔属性添加到ViewModel中，例如：

private bool _credentialVisible;
public bool CredentialVisible
{
    get 
    {
        return _credentialVisible;
    }
    set
    {
       if (_credentialVisible != value)
       {
           _credentialVisible = value;
           NotifyPropertyChanged();
       }
    }
}

您的视图模型应该实现接口

INotifyPropertyChanged

：

public event PropertyChangedEventHandler PropertyChanged;

protected void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

然后在视图中绑定到

IsVisible

属性：

<Button x:Name="Button_Round"
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" 
IsVisible="{Binding IsOfferButtonVisible}"
/>

<Button x:Name="Button_Round"
IsVisible={Binding CredentialVisible}
WidthRequest="40"
HeightRequest="40"
CornerRadius="20"
BorderWidth="2"
TextColor="White"
BorderColor="Teal"
BackgroundColor="Teal"
Text="Accept Offer"
Command="{Binding ProcessOffer}" />

然后您可以按如下方式使用它：

<ContentPage.Behaviors>
    <behaviors:EventHandlerBehavior EventName="Appearing">
        <behaviors:InvokeCommandAction Command="{Binding AppearingCommand}" />
    </behaviors:EventHandlerBehavior>
</ContentPage.Behaviors>

---

粘贴代码后，按钮隐藏，但如果状态更改，它仍然隐藏。。为什么？因为代码需要再次运行。是一个事件改变了它吗？如果是，那么在这种情况下，您应该重新检查值并重新分配可绑定属性，我添加了

公共bool IsOfferButtonVisible{get；private set；}

…我会看一看，看看是否可以：）粘贴代码后，按钮会隐藏，但如果状态更改，仍然会隐藏。。为什么？因为代码需要再次运行。是一个事件改变了它吗？如果是，那么在这种情况下，您应该重新检查值并重新分配可绑定属性，我添加了

公共bool IsOfferButtonVisible{get；private set；}

…我会看看是否可以：）谢谢您的回复，@Athanasios Kataras的回复更容易理解。谢谢您的回复，@Athanasios Kataras的答案更容易理解。