xamarin.forms

问题 I have built a xamarin forms app and android size 17mb using proguard, full linking. However UWP size is 76 mb. I am already using configuration as in the screenshot below. I am support x86, x64 and arm architectures on both platforms. in android i create separate packages per abi. thats why 17mb is each abi size. but I couldnt find a similar option in UWP. it is size of bundle. is there a way to provide 3 installers? Beside that why is the size too large and how can i optimize it further? PS

问题 So I am using the FreshMVVM Xamarin.Forms library so I can do ViewModel-first navigation in xamarin. My research tells me that this is a highly recommended practice, yet there seem to be not a whole lot of tutorials for this. What I am trying to achieve is a login page that pops up as a modal once the user opens the app if they are not signed in. I have modified the demo project slightly by adding the modal display button and associated Command from the ViewModel to the first page, however, I

问题 I have a xamarin forms app. There are 2 classes with data, one of the pages is filling the data. The problem is: I'm creating new view, that should use data from both classes. The only way i'm familiar with is to set a class as a bindingContext to pass data between pages, and it's working fine with ONE class, because apparently there couldn't be 2 bindingContext at the same time. EXAMPLE: 1st class (all the classes are filled on the previous page. just accept that they are filled) public

问题 I want to check if the file inside my device exist. When the variable crphoto1 is empty or the file does not exist the " Photo1 " json should be {"Photo1", ""} JObject ph1json = string.IsNullOrEmpty(crphoto1) ? new JObject { {"ContactID", crcontactID}, {"Photo1", ""} } : new JObject { {"ContactID", crcontactID}, {"Photo1", File.ReadAllBytes(crphoto1)} }; 回答1: If you are just looking for how to check if file exist you can use using System.IO; string fileName = Path.Combine(Environment

问题 I'm developing a xamarin.forms project using VS17. I have a build faild with this error: 1>System.IO.FileLoadException: Unable to load file or assembly 'Mono.Cecil.Pdb, Version = 0.10.0.0, PublicKeyToken = 50cebf1cceb9d05e' or one of its dependencies. Invalid parameter (Exception from HRESULT: 0x80070057 (E_INVALIDARG)) 1>File name: 'Mono.Cecil.Pdb, Version=0.10.0.0, PublicKeyToken=50cebf1cceb9d05e' ---> System.ArgumentException: Paramètre incorrect. (Exception de HRESULT : 0x80070057 (E

问题 I wanted to store and retrieve an array in a SQLite database in my Xamarin App. I'm following this Xamarin Tutorial on SQLite. These values will be then show in Picker . I used Models earlier to store array and then get the values and list it in Picker , it was working fine, but the only problem was that it wasn't stored permanently (by closing app array list get empty). Banks using SQLite; namespace Mobile.App { public class Banks { [PrimaryKey, AutoIncrement] public int ID { get; set; }

问题 In Visual Studio 2017, I start a brand new Xamarin.Forms solution, PCL and Blank App template. Here is what the MainPage.xaml content looks like: <Label Text="Welcome to Xamarin Forms!" VerticalOptions="Center" HorizontalOptions="Center" /> Using the Visual Studio Android emulator, I start a debug session, to confirm its working, and then close it. Then I make a small change the MainPage.xaml file, for example: <StackLayout HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand"

问题 In my Xamarin.iOS project I need to reduce the assembly size (Apple's requirement for AppStore applications), and I need to turn on linker, setting the linker behavior either to "Link Framework SDKs only" or "Link All". When I've selected "Link Framework SDKs only" in Linker behavior I get the compilation error upon building the project: Can't resolve the reference 'System.Void System.Data.SqlClient.SqlCommandBuilder::DeriveParameters(System.Data.SqlClient.SqlCommand)', referenced from the

问题 I'm using ServiceStack JsonHttpClient client (5.9.0) in my Xamarin.Forms mobile app. Client is set like this: client = new JsonHttpClient(App.BaseEndpoint) { RefreshToken = RefreshToken, }; var httpClient = client.GetHttpClient(); httpClient.Timeout = new TimeSpan(0, timeout, 0); Refreshing of Bearer token works perfect, but after Refresh Token expires request just hangs with no response and without any exception. here is request example: public async Task GetAsync(string uri) { try { var

问题 I would like to simplify the addition of dialog popups in my code to the absolute minimum needed. Currently I have this code: <pages:PopupPage x:Class="Test.Popup" xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"> <ContentView HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"> <t:PopupFrame> <Label Text="ABC" /> <Label Text="ABC" /> </t:PopupFrame> <