[英]Picker is not getting displayed in Xamarin.Forms app
我对xamarin非常陌生。 我正在开发我的第一个应用程序,其中 第一页显示用户名,密码和登录按钮b。 第二页显示一个下拉列表,因此我使用了选择器控件。 但是选择器未显示在我的应用程序屏幕上。(SecondPage)
应用程式
public class App : Application
{
public App()
{
MainPage = new MainPage();
}
protected override void OnStart()
{
// Handle when your app starts
}
protected override void OnSleep()
{
// Handle when your app sleeps
}
protected override void OnResume()
{
// Handle when your app resumes
}
}
MainPage.xaml.cs
public class MainPage : ContentPage
{
Entry UserName;
Entry Password;
Button LoginButton;
public MainPage()
{
this.Padding = new Thickness(20, 20, 20, 20);
StackLayout panel = new StackLayout
{
Spacing = 15
};
panel.Children.Add(UserName = new Entry
{
Placeholder = "Enter UserName",
});
panel.Children.Add(Password = new Entry
{
Placeholder = "Enter Password",
IsPassword = true,
});
panel.Children.Add(LoginButton = new Button
{
Text = "Login",
IsEnabled = true,
});
LoginButton.Clicked += OnLogin;
this.Content = panel;
}
private async void OnLogin(object sender, EventArgs e)
{
await Navigation.PushModalAsync(new SecondPage());
}
}
SecondPage.xaml.cs
public partial class SecondPage : ContentPage
{
public SecondPage()
{
StackLayout panel = new StackLayout
{
Spacing = 15
};
panel.Children.Add(new Label
{
Text = "Names of associates",
FontSize = Device.GetNamedSize(NamedSize.Medium, typeof(Label))
});
panel.Children.Add(new Label
{
Text = "Remarks",
FontSize = Device.GetNamedSize(NamedSize.Medium, typeof(Label))
});
this.Content = panel;
}
}
SecondPage.xaml
<StackLayout Padding ="10" Orientation="Vertical" >
<Picker x:Name="picker" Title="Select a monkey">
<Picker.ItemsSource>
<x:Array Type="{x:Type x:String}">
<x:String>Baboon</x:String>
<x:String>Capuchin Monkey</x:String>
<x:String>Blue Monkey</x:String>
<x:String>Squirrel Monkey</x:String>
<x:String>Golden Lion Tamarin</x:String>
<x:String>Howler Monkey</x:String>
<x:String>Japanese Macaque</x:String>
</x:Array>
</Picker.ItemsSource>
任何帮助深表感谢..
更新1:这对我有用。但是我不知道为什么使用ItemSource时会出现异常。
SecondPage.xaml
<?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="RegisterApp.SecondPage"
Title="Picker Test">
<StackLayout Padding="10" Orientation="Vertical" >
<Picker Title="Select a monkey">
<Picker.Items>
<x:String>Baboon</x:String>
<x:String>Capuchin Monkey</x:String>
<x:String>Blue Monkey</x:String>
<x:String>Squirrel Monkey</x:String>
<x:String>Golden Lion Tamarin</x:String>
<x:String>Howler Monkey</x:String>
<x:String>Japanese Macaque</x:String>
</Picker.Items>
</Picker>
</StackLayout>
</ContentPage>
这对我有用
<?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="ScratchPad.Pages.MainPage"
Title="Picker Test">
<StackLayout Padding="10" Orientation="Vertical" >
<Picker x:Name="picker" Title="Select a monkey">
<Picker.ItemsSource>
<x:Array Type="{x:Type x:String}">
<x:String>Baboon</x:String>
<x:String>Capuchin Monkey</x:String>
<x:String>Blue Monkey</x:String>
<x:String>Squirrel Monkey</x:String>
<x:String>Golden Lion Tamarin</x:String>
<x:String>Howler Monkey</x:String>
<x:String>Japanese Macaque</x:String>
</x:Array>
</Picker.ItemsSource>
</Picker>
</StackLayout>
</ContentPage>
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