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我正在創建一個Xamarin.Forms便攜式應用程序。我在我的Visual Studio中有一個數據庫，我想將其中的數據顯示到Xamarin ListView中。但是每當我這樣做時，數據就不會顯示在我的Xamarin.Droid上，只留下一個空白區域。我在UWP中嘗試過它，它工作。我將如何在我的Xamarin.Droid中做到這一點？Xamarin.Forms：ListView不會顯示在Xamarin.Droid
（我Xamarin.Droid截圖）
注意ListView控件仍然佔據即使不被顯示的所有記錄的空間。你認爲這背後的原因是什麼？我甚至在我的WEB API中檢查這個數據是否正在被檢索並且IT是否可用。
意思是，真正的問題只發生在顯示ListView上的記錄。希望您能夠幫助我。
這是我試過的代碼。
ClientList.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="XamarinFormsDemo.Views.ClientListPage"
xmlns:ViewModels="clr-namespace:XamarinFormsDemo.ViewModels;assembly=XamarinFormsDemo"
xmlns:controls="clr-namespace:ImageCircle.Forms.Plugin.Abstractions;assembly=ImageCircle.Forms.Plugin.Abstractions"
BackgroundImage="bg3.jpg"
Title="Client List">
<ContentPage.BindingContext>
<ViewModels:CustomerVM/>
</ContentPage.BindingContext>
<StackLayout Orientation="Vertical">
<SearchBar Placeholder="Search" Text="{Binding Keyword}" SearchCommand="{Binding SearchCommand}" x:Name="txtSearch" />
<ListView ItemsSource="{Binding CustomerList}"
HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid Padding="10" RowSpacing="10" ColumnSpacing="5">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<controls:CircleImage Source="icon.png"
HeightRequest="66"
HorizontalOptions="CenterAndExpand"
Aspect="AspectFill"
WidthRequest="66"
Grid.RowSpan="2"
/>
<Label Grid.Column="1"
Text="{Binding CUSTOMER_NAME}"
TextColor="#24e97d"
FontSize="24"/>
<Label Grid.Column="1"
Grid.Row="1"
Text="{Binding CUSTOMER_CODE}"
TextColor="White"
FontSize="18"
Opacity="0.6"/>
<Label Grid.Column="1"
Grid.Row="2"
Text="{Binding CUSTOMER_CONTACT}"
TextColor="White"
FontSize="18"
Opacity="0.6"/>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<StackLayout Orientation="Vertical"
Padding="30,10,30,10"
HeightRequest="20"
BackgroundColor="#24e97d"
VerticalOptions="Center"
Opacity="0.5">
<Label Text="© Copyright 2016 SMESOFT.COM.PH All Rights Reserved "
HorizontalTextAlignment="Center"
VerticalOptions="Center"
HorizontalOptions="Center" />
</StackLayout>
</StackLayout>
</ContentPage>
ClientListViewModel.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using Xamarin.Forms;
using XamarinFormsDemo.Models;
using XamarinFormsDemo.Services;
namespace XamarinFormsDemo.ViewModels
{
public class CustomerVM : INotifyPropertyChanged
{
private List<Customer> _customerList; // keep all customers
private List<Customer> _searchedCustomerList; // keep a copy for searching
private Customer _selectedCustomer = new Customer();
private string _keyword = "";
public string Keyword
{
get
{
return _keyword;
}
set
{
this._keyword = value;
// while keyword changed we filter Employees
//Filter();
}
}
private void Filter()
{
if (string.IsNullOrWhiteSpace(_keyword))
{
CustomerList = _searchedCustomerList;
}
else
{
// var lowerKeyword = _keyword.ToLower();
CustomerList = _searchedCustomerList.Where(r => r.CUSTOMER_NAME.ToLower().Contains(_keyword.ToLower())).ToList();
// EmployeesList = _searchedEmployeesList.Where(r => r.EMPLOYEE_NAME.Contains(_keyword)).ToList();
}
}
public List<Customer> CustomerList
{
get
{
return _customerList;
}
set
{
_customerList = value;
OnPropertyChanged();
}
}
public ICommand SearchCommand
{
get
{
return new Command((sender) =>
{
//var searchBar = (SearchBar)sender;
//this.Keyword = searchBar.Text;
Filter();
});
}
}
public CustomerVM()
{
InitializeDataAsync();
}
private async Task InitializeDataAsync()
{
var customerServices = new CustomerServices();
_searchedCustomerList = await customerServices.GetCustomerAsync();
CustomerList = await customerServices.GetCustomerAsync();
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
CustomerService.cs
using Plugin.RestClient;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using XamarinFormsDemo.Models;
namespace XamarinFormsDemo.Services
{
public class CustomerServices
{
public async Task<List<Customer>> GetCustomerAsync()
{
RestClient_Customer<Customer> restClient = new RestClient_Customer<Customer>();
var customerList = await restClient.GetCustomerAsync();//yung getasync ay pantawag as restclient
return customerList;
}
}
}
個RestClient.cs
public class RestClient_Customer <T>
{
private const string WebServiceUrl = "http://localhost:50857/api/Customer/";
public async Task<List<T>> GetCustomerAsync()
{
var httpClient = new HttpClient();
var json = await httpClient.GetStringAsync(WebServiceUrl);
var taskModels = JsonConvert.DeserializeObject<List<T>>(json);
return taskModels;
}
}
嘗試，作爲一個測試，刪除'ListView'附近的'StackLayout' –
@GeraldVersluis我已經試過了，先生。但仍然沒有顯示ListView。 –