Question

我正在使用laravel和php，我正在做一个递归函数，问题是该函数的return值不能正常工作echo。

代码就是这个。

public function getSitioPadre($id){
    $padre =  md_sitio_espacios::where([['SITIO_ESPACIOS_ID','=',$id]])->get()->toArray();       
    if($padre[0]["PADRE"] == 0){
        return $padre[0]["SITIO_ESPACIOS_ID"];
    }else{
        $this->getSitioPadre($padre[0]["PADRE"]);
    }
}

当我称这个函数为：

echo $this->getSitioPadre(54);

什么都不返回，

如果在我使用的函数中使用：echo $padre[0]["SITIO_ESPACIOS_ID"]而不是return，则可以使用。

让我知道我能做些什么，谢谢。

Answer 1

你似乎没有在你的其他条款中返回任何内容。

# 1
# Compiles. On Windows throws System.InvalidCastException: 
# 'Unable to cast object of type 'Xamarin.Forms.Binding' 
# to type 'System.Boolean'.'
<ActivityIndicator x:Name="AI" IsEnabled="{Binding Path=IsBusy}" IsRunning="{Binding Path=IsBusy}">
    <ActivityIndicator.IsVisible>
        <OnPlatform x:TypeArguments="x:Boolean">
            <On Platform="Android" Value="True"/>
            <On Platform="iOS" Value="True"/>
            <On Platform="Windows" Value="{Binding Path=IsBusy}"/>
        </OnPlatform>
    </ActivityIndicator.IsVisible>
</ActivityIndicator>

# 2
# Doesn't compile. Gives an error saying "No property, 
# bindable property, or event found for 'IsVisible'"
<ActivityIndicator x:Name="AI" IsEnabled="{Binding Path=IsBusy}" IsVisible="True" IsRunning="{Binding Path=IsBusy}">
    <ActivityIndicator.IsVisible>
        <OnPlatform x:TypeArguments="BindingBase">
            <On Platform="Windows" Value="{Binding Path=IsBusy}"/>
        </OnPlatform>
    </ActivityIndicator.IsVisible>
</ActivityIndicator>

# 3
# Doesn't compile. Gives an error saying "No property, 
# bindable property, or event found for 'IsVisible'"
<ActivityIndicator x:Name="AI" IsEnabled="{Binding Path=IsBusy}" IsVisible="True" IsRunning="{Binding Path=IsBusy}">
    <ActivityIndicator.IsVisible>
        <OnPlatform x:TypeArguments="Binding">
            <On Platform="Windows" Value="{Binding Path=IsBusy}"/>
        </OnPlatform>
    </ActivityIndicator.IsVisible>
</ActivityIndicator>

# 4
# Compiles. On Windows throws System.InvalidCastException: 
# 'Unable to cast object of type 'Xamarin.Forms.Binding' 
# to type 'System.Boolean'.'
<ActivityIndicator x:Name="AI" IsEnabled="{Binding Path=IsBusy}" IsVisible="True" IsRunning="{Binding Path=IsBusy}">
    <ActivityIndicator.IsVisible>
        <OnPlatform x:TypeArguments="x:Boolean">
            <On Platform="Windows">
                <Binding Path="IsBusy" />
            </On>
        </OnPlatform>
    </ActivityIndicator.IsVisible>
</ActivityIndicator>

返回递归函数PHP laravel

1 个答案: