Question

我正在设置一个跨平台应用程序。如何使输入字符串的格式正确

这是Xamarim.forms项目

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
 x:Class="TestProjectXamarin.Views.DetailViews.InfoScren1">
<ContentPage.Content>
    <StackLayout x:Name="MainLayout">
        <RelativeLayout VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
            <StackLayout x:Name="SubLayout"
                         Orientation="Vertical"
                         VerticalOptions="FillAndExpand"
                         RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=e}"
                         RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=e}">
                <Label Text="Let's see the bla bla bla Over Here" HorizontalOptions="Center" VerticalOptions="Center"/>

            </StackLayout>

            <ActivityIndicator IsRunning="True" Color="Gray" x:Name="ActivitySpinner"
                               VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand"
                               RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=width, Factor=0.45}"
                               RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0.45}"/>

        </RelativeLayout>

    </StackLayout>
</ContentPage.Content>

我希望代码没有错误，但是它告诉我输入字符串的格式不正确

Answer 1

您得到的错误是因为您正在分配Constant=e，并且Constant必须获得一个值。

常量–用作值的偏移量的值。

此外，在您的ActivityIndicator中，该属性为Width。

这是您的样品。根据需要调整“常数”值。

 <StackLayout x:Name="MainLayout">
        <RelativeLayout VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
            <StackLayout x:Name="SubLayout"
                         Orientation="Vertical"
                         VerticalOptions="FillAndExpand"
                         RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=1}"
                         RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=1}">
                <Label Text="Let's see the bla bla bla Over Here" HorizontalOptions="Center" VerticalOptions="Center"/>

            </StackLayout>

            <ActivityIndicator IsRunning="True" Color="Gray" x:Name="ActivitySpinner"
                               VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand"
                               RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.45}"
                               RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0.45}"/>

        </RelativeLayout>

    </StackLayout>

有关RelativeLayouts的更多信息，请检查docs

如何解决输入字符串格式不正确的问题

1 个答案: