I am using xamarin.forms. having two projects Android and IOS.
I have one ContentView page with following code
<ContentView.Content>
<StackLayout x:Name="slMain" Padding="1" BackgroundColor="#7ABA45">
<StackLayout VerticalOptions="FillAndExpand" Padding="0,0,20,0" HeightRequest="50" HorizontalOptions="FillAndExpand">
<Label x:Name="lblTitle" VerticalOptions="CenterAndExpand" />
</StackLayout>
<StackLayout x:Name="sl" IsVisible="False" BackgroundColor="White">
</StackLayout>
</StackLayout>
</ContentView.Content>
// In Behind code(.cs file)
public ExpandCollapseStackLayout()
{
InitializeComponent();
var tapGestureRecognizer = new TapGestureRecognizer();
tapGestureRecognizer.Tapped += (s, e) =>
{
sl.IsVisible = !sl.IsVisible;
};
lblTitle.GestureRecognizers.Add(tapGestureRecognizer);
slMain.GestureRecognizers.Add(tapGestureRecognizer);
}
public string Title
{
get
{
return lblTitle.Text;
}
set
{
lblTitle.Text = value;
}
}
I want to add controls in StackLayout named "sl" of contentview in ContentPage at design time.
I dont want to add at runtime
Please suggest me how can I add Control in Contentview stacklayout?
If you want to add controls in design time simply declare them in your XAML, example:
<StackLayout x:Name="sl" IsVisible="False" BackgroundColor="White">
<!-- Add here your controls -->
<Label ... />
<Button .. />
</StackLayout>
If you want to add controls at runtime, you need to do it using your code behind page in C#. Example:
void AddControl()
{
var btn = new Button();
sl.Children.Add(btn);
}
Code for ContentView:
<ContentView.Content>
<StackLayout x:Name="slMain" Padding="1" BackgroundColor="#7ABA45" >
<StackLayout VerticalOptions="FillAndExpand" Padding="0,0,10,0" HeightRequest="50" HorizontalOptions="FillAndExpand" Orientation="Horizontal">
<Label x:Name="lblTitle" VerticalOptions="CenterAndExpand" HorizontalOptions="FillAndExpand" Margin="10,0,0,0" TextColor="White" FontAttributes="Bold" />
<Label Text="{ x:Static local:GrialShapesFont.ArrowDown }" HorizontalOptions="End" VerticalOptions="CenterAndExpand" TextColor="White" Style="{ StaticResource FontIconBase }" FontSize="26" />
</StackLayout>
<Frame Padding="10" IsVisible="False" BackgroundColor="White" x:Name="ContentFrame" OutlineColor="Black" HasShadow="False">
</Frame>
</StackLayout>
</ContentView.Content>
CS Code for ContentView:
[ContentProperty("ContainerContent")]
public partial class ExpandCollapseStackLayout : ContentView
{
public ExpandCollapseStackLayout()
{
InitializeComponent();
var tapGestureRecognizer = new TapGestureRecognizer();
tapGestureRecognizer.Tapped += (s, e) =>
{
ContentFrame.IsVisible = !ContentFrame.IsVisible;
};
lblTitle.GestureRecognizers.Add(tapGestureRecognizer);
slMain.GestureRecognizers.Add(tapGestureRecognizer);
}
public View ContainerContent
{
get { return ContentFrame.Content; }
set { ContentFrame.Content = value; }
}
public string Title
{
get
{
return lblTitle.Text;
}
set
{
lblTitle.Text = value;
}
}
}
Add Control in ContentPage:
<control:ExpandCollapseStackLayout Title="Demo" Padding="0,10,0,0">
<control:ExpandCollapseStackLayout.ContainerContent >
<StackLayout>
<Label Text="Add Content Here"></Label>
</StackLayout>
</control:ExpandCollapseStackLayout.ContainerContent>
</control:ExpandCollapseStackLayout>
Related
I want to know how do I pass data from one CollectionView which is in my MainPage.xaml to another page called DetailsPage when user clicks on a frame that is inside a CollectionView, I hope you know what I meant.
This is my MainPage.xaml:
<CollectionView x:Name="CVSubjects" Margin="0,-50,0,0" ItemsLayout="HorizontalList">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout Margin="20,0,0,0">
<Frame BackgroundColor="{Binding BackgroundColor}" WidthRequest="250" HeightRequest="180" HorizontalOptions="Center" CornerRadius="30">
<Frame.GestureRecognizers>
<TapGestureRecognizer Tapped="TapGestureRecognizer_Tapped"/>
</Frame.GestureRecognizers>
<StackLayout>
<Frame BackgroundColor="white" HasShadow="False" WidthRequest="30" HorizontalOptions="Start" CornerRadius="50" HeightRequest="10">
<StackLayout Orientation="Horizontal" HeightRequest="10">
<Image Source="redstaricon.png" WidthRequest="14" Margin="-10,-2,0,0"></Image>
<Label Text="{Binding Rating}" VerticalOptions="Center" Margin="0,-5,0,0" FontAttributes="Bold" TextColor="Black"></Label>
</StackLayout>
</Frame>
<Label Text="{Binding Name}" FontSize="21" TextColor="White" FontAttributes="Bold" Padding="0,10,0,0" WidthRequest="250"></Label>
<StackLayout Orientation="Horizontal">
<Frame CornerRadius="100"
HeightRequest="55"
WidthRequest="60"
HorizontalOptions="Center"
Padding="0"
IsClippedToBounds="True"
Margin="0,20,0,0"
>
<Image Source="{Binding ImageUrl}"
HorizontalOptions="Center"
VerticalOptions="Center"
Aspect="Fill"></Image>
</Frame>
<Label Text="Teacher" TextColor="White" WidthRequest="100" Margin="0,25,0,0">
</Label>
<Label Text="{Binding Teacher}" VerticalOptions="Center" TextColor="White" WidthRequest="200" FontAttributes="Bold" Margin="-100,45,0,0" FontSize="17">
</Label>
</StackLayout>
</StackLayout>
</Frame>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
and this is MainPage.xaml.cs:
public partial class MainPage : ContentPage
{
ObservableCollection<Subjects> subjects;
public MainPage()
{
InitializeComponent();
subjects = new ObservableCollection<Subjects>() { new Subjects { Id = 1, Name = "UX - UI Design", Teacher = "Gustavo Kenter", Rating = "4.9", BackgroundColor = "#FE2E47", ImageUrl="teacher1.png", TeacherTitle="Designer" },
new Subjects{Id = 2, Name = "Animation in After Effects", Teacher = "Tiana Mango", Rating = "4.3", BackgroundColor = "#FDB2C0", ImageUrl="teacher2.png", TeacherTitle="Animator" },
new Subjects{Id = 3, Name = "Mobile App Design", Teacher = "Dulce Bator", Rating = "4.1", BackgroundColor = "#D0BCD0", ImageUrl="teacher3.png", TeacherTitle="Designer" },
new Subjects {Id = 4, Name = "3D Design", Teacher = "Lincoln Bator", Rating = "4.6", BackgroundColor = "#88B5FC", ImageUrl="teacher4.png", TeacherTitle="3D Designer" },
new Subjects{ Id = 5, Name = "Mobile App Development", Teacher = "Livia Lubin", Rating = "4.7", BackgroundColor = "#FDB2C0", ImageUrl="teacher5.png", TeacherTitle="Developer" } };
GetSubjects();
}
private void GetSubjects()
{
CVSubjects.ItemsSource = subjects;
CVGridSubjects.ItemsSource = subjects;
}
private void TapGestureRecognizer_Tapped(object sender, EventArgs e)
{
Navigation.PushModalAsync(new DetailsPage());
}
}
How do I know pass the data from my CollectionView, I have tried to pass the data through parameters but for some reason when I add a name to for example a lable that contains the name of the subject, I cannot access it inisde c# code, anyone knows how to fix this?
CollectionView has built in events for handling selection, it is not neccesary to use a GestureRecognizer
<CollectionView SelectionMode="Single"
SelectionChanged="OnCollectionViewSelectionChanged" ... >
then you can pass the selected item to the next page via it's constructor
void OnCollectionViewSelectionChanged(object sender, SelectionChangedEventArgs e)
{
var current = (e.CurrentSelection.FirstOrDefault() as Subjects);
Navigation.PushModalAsync(new DetailsPage(current));
}
I'm building a shopping cart and I have a very annoying problem with a double toolbar being displayed on my pages.
I spent several hours on this and having issues trying to fix it.
My current pages are setup like so:
MainHomePage (This contains a menu and an embedded page titled "MainHomePageDetail")
MainHomePageDetail (this contains a list of images where the user will click on it and it will take them to other pages as well.
PageBulkBuys (This is one of the pages that displays the product details etc)
Problem to be fixed.
I just want to remove the double toolbar that's currently being displayed on the homepage and also the subpages.
Note that if I were to click on one of the menu links, this problem disappears and it only shows one tool bar.
However If I click on one of the links in the homepage, it shows a double tool bar which is really strange.
I've tried a few solutions online but no luck.
Here's my code:
App.CS
public App()
{
InitializeComponent();
MainPage = new NavigationPage(new MainHomePage());
}
MainHomePage XAML
<?xml version="1.0" encoding="utf-8"?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="xxxxx.MainHomePage" xmlns:pages="clr-namespace:xxxxx">
<MasterDetailPage.Master>
<pages:MainHomePageMaster x:Name="MasterPage" />
</MasterDetailPage.Master>
<MasterDetailPage.Detail>
<NavigationPage BarBackgroundColor="Black">
<x:Arguments>
<pages:MainHomePageDetail />
</x:Arguments>
</NavigationPage>
</MasterDetailPage.Detail>
</MasterDetailPage>
MainHomePage CS
public partial class MainHomePage : MasterDetailPage
{
public MainHomePage()
{
InitializeComponent();
MasterPage.ListView.ItemSelected += ListView_ItemSelected;
}
[Obsolete]
private void ListView_ItemSelected(object sender, SelectedItemChangedEventArgs e)
{
var item = e.SelectedItem as MainHomePageMenuItem;
if (item == null)
return;
if (item.Id == 10) // BulkBuys
Navigation.PushAsync(new BulkBuys());
}
}
MainHomePageDetail 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="xxxx.MainHomePageDetail" Title="xxxx" BackgroundColor="Black">
<ContentPage.ToolbarItems>
<ToolbarItem Name="shoppingcarticon" IconImageSource="xxxxxx.png" Priority="0" Order="Primary" Activated="ShoppingCartClicked"/>
</ContentPage.ToolbarItems>
<StackLayout Padding="10">
<ScrollView HorizontalOptions="FillAndExpand">
<StackLayout>
<Image Source="xxxxx.png" WidthRequest="600" HeightRequest="50"/>
<Label x:Name="labelLoggedInUser" TextColor="White" FontAttributes="Bold" FontSize="18"></Label>
<!-- Banner 1 -->
<Frame x:Name="frame1" BackgroundColor="#2e2e2e">
<StackLayout>
<Image x:Name="Banner1Image" WidthRequest="600" HeightRequest="200">
<Image.GestureRecognizers>
<TapGestureRecognizer
Tapped="BtnBulkBargains"
NumberOfTapsRequired="1" />
</Image.GestureRecognizers>
</Image>
<Frame BackgroundColor="Green" HasShadow="False" Padding="5" HorizontalOptions="Center" WidthRequest="250" HeightRequest="20" CornerRadius="00">
<Label x:Name="Banner1Text" FontAttributes="Bold" FontSize="18" TextColor="White" WidthRequest="80" HorizontalTextAlignment="Center" ></Label>
</Frame>
<Label x:Name="Banner1Header" TextColor="White" HorizontalTextAlignment="Center"></Label>
</StackLayout>
</Frame>
<!-- Banner 2 -->
<Frame x:Name="frame2" BackgroundColor="#2e2e2e">
<StackLayout>
<Image x:Name="Banner2Image" WidthRequest="600" HeightRequest="125"></Image>
</StackLayout>
</Frame>
MainHomePageDetail CS
public MainHomePageDetail()
{
InitializeComponent();
}
private void ShoppingCartClicked(object sender, EventArgs e)
{
Navigation.PushAsync(new ViewFBShoppingCart());
}
BulkBuysPage 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="xxxx.PageBulkBuys"
Title="Bulk Buys"
BackgroundColor="Black"
NavigationPage.HasBackButton="True">
<ContentPage.ToolbarItems>
<ToolbarItem Name="shoppingcarticon" IconImageSource="xxxx.png" Priority="0" Order="Primary" Activated="ShoppingCartClicked"/>
</ContentPage.ToolbarItems>
<ContentPage.Content>
<StackLayout>
<Image Source="xxxx.png" WidthRequest="600" HeightRequest="50"/>
<ListView x:Name="productsListView"
HasUnevenRows="True"
VerticalOptions="FillAndExpand"
SeparatorVisibility="None"
ItemSelected="OnItemSelected">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<Frame HasShadow="True" Padding="20" Margin="20">
<StackLayout>
<Image Source="{Binding featured_src}"/>
<Label x:Name="labelProductTitle" Text="{Binding title}" FontSize="Medium" />
<Frame BackgroundColor="Red" Padding="5" HorizontalOptions="Center" WidthRequest="80" HeightRequest="20" CornerRadius="00">
<Label WidthRequest="40" Text="{Binding price, StringFormat='${0}'}" TextColor="White" HorizontalTextAlignment="Center"></Label>
</Frame>
</StackLayout>
</Frame>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage.Content>
</ContentPage>
BulkBuysPage CS
public PageBulkBuys()
{
InitializeComponent();
}
private void ShoppingCartClicked(object sender, EventArgs e)
{
Navigation.PushAsync(new ViewFBShoppingCart());
}
Any help would greatly be appreciated.
Because you used the NavigationPage in your App.cs,it will create a toolbar for you：
MainPage = new NavigationPage(new MainHomePage());
try to change it to :
MainPage = new MainHomePage();
or use NavigationPage.SetHasNavigationBar method in your MainHomePage to hide the toolbar :
public App()
{
InitializeComponent();
MainPage = new NavigationPage(new MainHomePage());
}
public MainHomePage()
{
InitializeComponent();
NavigationPage.SetHasNavigationBar(this, false);
MasterPage.ListView.ItemSelected += ListView_ItemSelected;
}
I have a screen that captures digital signature which, when saving or returning, executes a postasync or postmodalasync when the screen returns to me does not reload. How can I make the page reload or refresh?
<Grid BackgroundColor="WhiteSmoke" Padding="0" RowSpacing="0" VerticalOptions="StartAndExpand">
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ContentView Margin="10,0,10,5" Padding="0" BackgroundColor="LightGray" HeightRequest="500">
<StackLayout Padding="5,0,5,5" BackgroundColor="White" Spacing="1">
<Label
Text="Firma Policia Que Realizo Visita"
HorizontalOptions="Center"
TextColor="Black"
FontSize="Large"
FontAttributes="Bold"
/>
<Frame HasShadow="true"
Padding="8"
VerticalOptions="CenterAndExpand">
<signature:SignaturePadView
x:Name="SignatureView"
BindingContext="{Binding SignatureView}"
WidthRequest="280"
HeightRequest="300"
CaptionText=""
CaptionTextColor="Blue"
ClearText=""
PromptText=""
PromptTextColor="Green"
BackgroundColor="WhiteSmoke"
SignatureLineColor="Black"
StrokeWidth="3"
StrokeColor="Black" />
</Frame>
</StackLayout>
</ContentView>
</Grid>
<StackLayout Orientation="Horizontal" Padding="2" Spacing="2">
<Button
HorizontalOptions="FillAndExpand"
HeightRequest="40"
Text="Guardar"
TextColor="{x:StaticResource WhiteColor}"
FontSize="Small"
VerticalOptions="Center"
BackgroundColor="{x:StaticResource GreenButton}"
Clicked="Button_Clicked">
</Button>
<Button
HorizontalOptions="FillAndExpand"
HeightRequest="40"
Text="Limpiar"
TextColor="{x:StaticResource WhiteColor}"
FontSize="Small"
VerticalOptions="Center"
BackgroundColor="{x:StaticResource SicoqYellowColor}"
Clicked="Button_Clicked_1">
</Button>
</StackLayout>
This is the viewmodel which makes the backbuttoncommand service
public Task RemoveLastModalFromBack(object parameter,bool animated = false)
{
var mainPage = Application.Current.MainPage as NavigationView;
if (mainPage != null)
{
mainPage.Navigation.PopAsync(animated);
}
return Task.FromResult(true);
}
This is the ViewModel which receives the signature data
private async Task BackButton()
{
try
{
IsBusy = true;
await NavigationService.RemoveLastModalFromBack(str3);
o
}
catch (Exception e)
{
IsBusy = false;
// await DialogService.DisplayAlertAsync("Error", e.Message, "Aceptar");
}
finally
{
IsBusy = false;
}
}
The digital signature master page is digital signatures when you save or return the digital signatures page to reload
Do you want to achieve the result like following GIF?
If so, you can use MessagingCenter to achieve that.
We can use send method of MessagingCenter, Here is my code in the Button click event of SignaturesPage,Use the MessagingCenter to send the data to the MainPage.
private async void Button_Clicked(object sender, EventArgs e)
{
//get stream of Signatures from the pad
Stream image = await SignaturePad.GetImageStreamAsync(SignatureImageFormat.Png);
MessagingCenter.Send<Stream>(image, "Image");
await Navigation.PopAsync();
}
In the MainPage, I layout have Image to wait the stream from the SignaturesPage.
<StackLayout>
<!-- Place new controls here -->
<Frame BorderColor="Orange"
CornerRadius="10"
HasShadow="True">
<Button AutomationId="Mybutton" Text="Save" x:Name="Mybutton" HorizontalOptions="CenterAndExpand" Clicked="Mybutton_Clicked"/>
</Frame>
<Frame BorderColor="Orange"
CornerRadius="10"
HasShadow="True">
<Image x:Name="MyImage" HeightRequest="500" WidthRequest="400"/>
</Frame>
</StackLayout>
Here is my background code in the MainPage.
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
MessagingCenter.Subscribe<Stream>(this, "Image", (arg) =>
{
MyImage.Source = ImageSource.FromStream(() => arg);
});
}
protected override void OnAppearing()
{
base.OnAppearing();
}
private void Mybutton_Clicked(object sender, EventArgs e)
{
Navigation.PushAsync(new SignaturesPage());
}
}
Is there a way to use absolute layout as a customize pop-up? I am trying to create a customize popup. Is this possible?
<StackLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BackgroundColor="Yellow">
//Elements here
</StackLayout>
<AbsoluteLayout StyleClass="dialogbox" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
//Popup here
</AbsoluteLayout>
You can achieve that with AbsoluteLayout and add a fade animation. Here is running GIF.
There is code.
<StackLayout>
<Button
x:Name="btn"
Text="click"
/>
<ContentView x:Name="popupLoginView" BackgroundColor="#C0808080" Padding="10, 0" IsVisible="false" AbsoluteLayout.LayoutBounds="0, 0, 1, 1" AbsoluteLayout.LayoutFlags="All">
<AbsoluteLayout VerticalOptions="Center" HorizontalOptions="Center">
<StackLayout Orientation="Vertical" HeightRequest="200" WidthRequest="300" BackgroundColor="White">
<Entry Margin="20,20,20,10" Placeholder="Enter Username"></Entry>
<Entry Margin="20,0,20,0" Placeholder="Enter Password"></Entry>
<Button Margin="20,0,20,0" Text="Login"></Button>
</StackLayout>
</AbsoluteLayout>
</ContentView>
</StackLayout>
In xamarin forms, you can add fade animation to view. There is animation code.
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
btn.Clicked += Btn_Clicked;
}
private async void Btn_Clicked(object sender, EventArgs e)
{
if (popupLoginView.IsVisible==true)
{
btn.IsEnabled = false;
await popupLoginView.FadeTo(0,2000);
await Task.Delay(2000);
popupLoginView.Opacity = 0;
popupLoginView.IsVisible = false;
btn.IsEnabled = true;
return;
}
if (popupLoginView.IsVisible == false)
{
if (popupLoginView.Opacity==1)
{
popupLoginView.Opacity = 0;
}
popupLoginView.IsVisible = true;
btn.IsEnabled = false;
await popupLoginView.FadeTo(1, 2000);
await Task.Delay(2000);
btn.IsEnabled = true;
popupLoginView.Opacity = 1;
return;
}
}
}
There is article about fade animation.
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/animation/simple#fading
If you want to achieve it with Rg.Plugins.Popup and add the animation, you can refer to this article, it will add some animations.
https://www.c-sharpcorner.com/article/learn-about-xamarin-forms-animation-with-popuppage/
After press, the return button on-screen keyboard the listview hide from the iOS screen. The same code is running perfectly on Android. I have create the 30 second video that will help you understand the problem.
The code file and Video can be download from here https://drive.google.com/drive/folders/1Q4O1KexIHvrCX79AR3CesRXJRWM1o2JR?usp=sharing
<ListView x:Name="listViewOrder" ItemTapped="OnActivitySelected" HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Frame HasShadow="True" OutlineColor="Silver" Padding="3">
<Grid BackgroundColor="{Binding RowColour}" ColumnSpacing="2" Padding="2">
<StackLayout Orientation="Horizontal" HeightRequest="35" BackgroundColor="{Binding RowColour}" Padding="10">
<StackLayout Spacing="0" BackgroundColor="{Binding RowColour}" Orientation="Horizontal" HorizontalOptions="Start">
<Label FontSize="Medium" TextColor="#707070" Text="{Binding GFIELD3}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"/>
</StackLayout>
<StackLayout Spacing="0" BackgroundColor="{Binding RowColour}" Orientation="Horizontal" HorizontalOptions="EndAndExpand">
<Image Aspect="AspectFit" Source = "{Binding ImageStatus}" HorizontalOptions="StartAndExpand" VerticalOptions="Center" HeightRequest = "20" WidthRequest="20" />
</StackLayout>
</StackLayout>
</Grid>
</Frame>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<StackLayout x:Name="layoutForBluetooth" HeightRequest="200" Padding="5, 5, 5, 5" BackgroundColor="#5DCBEE" Orientation="Horizontal" HorizontalOptions="FillAndExpand">
<Frame Padding="5,5,5,5" HorizontalOptions="FillAndExpand" OutlineColor="Black" HasShadow="True">
<Grid>
<Label Text="Scan Your Barcode" x:Name="lblDriverNumber" TextColor="Black" FontSize="Medium" HorizontalOptions="FillAndExpand" Margin="0,10" />
<Entry x:Name="txtentry" FontSize="Medium" TextColor="Black" WidthRequest="400" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand" />
</Grid>
</Frame>
async void Txtentry_Completed(object sender, EventArgs e)
{
BiendListview(orderID);
}
public void BiendListview(int OID)
{
try
{
List<GenericFields> GN = new List<GenericFields>();
GN = GetDeliveryOrderItems(OID);
if (GN != null)
{
// listViewOrder.BeginRefresh();
listViewOrder.ItemsSource = GN;
// listViewOrder.EndRefresh();
}
}
catch (Exception ex)
{
}
}
Please make a breakpoint to debug your GN's value. From your code:
if (GN != null)
{
// listViewOrder.BeginRefresh();
listViewOrder.ItemsSource = GN;
// listViewOrder.EndRefresh();
}
This if statement will always be true, since you have construct the GN by List<GenericFields> GN = new List<GenericFields>();. It will never be null.
You can try to modify it to:
if (GN.Count != 0)
{
// listViewOrder.BeginRefresh();
listViewOrder.ItemsSource = GN;
// listViewOrder.EndRefresh();
}