Xamarin.Forms中在ListView中使用Command

注意事项：

        1、在ListView中无法直接绑定Command需要这样写

Command="{Binding BindingContext.ClaimAssignmentClickCommand,Source={x:Reference cpg}}"

其中cpg是界面名称

2、传递参数

ListView绑定的数据源：

 <ListView x:Name="lv_QMSampList" RowHeight="-1" HasUnevenRows="True" BackgroundColor="#ECECEC" ItemsSource="{Binding QmSampListItemsSource}"  SeparatorVisibility="None">
</ListView>

我想将ListView绑定的参数传递给Command

CommandParameter="{Binding .}"

3、ViewModel中接收

public QMSampAssignmentViewModel(BsUserList user, QMSampAssignmentPage page)
        {
            this.user = user;
            this.page = page;


            ClaimAssignmentClickCommand = new Command<QMSampingListItem>(async (item) => await BtnClaimAssignmentClick(item));
        }



public async Task BtnClaimAssignmentClick(QMSampingListItem item) {
            if (!XaApp.App.IsNetAvailable)
                await page.DisplayAlert("错误", "无网络连接", "确定");

          
        }

源码：

1、创建界面

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
             xmlns:resources="clr-namespace:ErpApp.Resources"
             mc:Ignorable="d"
             Title="领取取样任务"
             x:Name="cpg"
             x:Class="ErpApp.Views.QMSamping.QMSampAssignmentPage" >
    <ContentPage.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <resources:Colors />
                <resources:Styles />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </ContentPage.Resources>
    <ContentPage.Content>
        <StackLayout>

            <StackLayout>
                <!--<ScrollView>-->
                <ListView x:Name="lv_QMSampList" RowHeight="-1" HasUnevenRows="True" BackgroundColor="#ECECEC" ItemsSource="{Binding QmSampListItemsSource}"  SeparatorVisibility="None">
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <ViewCell>
                                <ContentView Padding="5,5">
                                    <Frame Padding="1" CornerRadius="10">
                                        <StackLayout Padding="8,8,0,8">
                                            <StackLayout Orientation="Horizontal">
                                                <Label Text="库　　位:" FontAttributes="Bold" VerticalOptions="CenterAndExpand" HorizontalOptions="Start"></Label>
                                                <Label Text="{Binding STORELOCA_NAME}" VerticalOptions="CenterAndExpand" HorizontalOptions="StartAndExpand"></Label>

                                                <Button Text="领取任务" 
                                                        HorizontalOptions="Start" 
                                                        VerticalOptions="CenterAndExpand"
                                                        Style="{StaticResource PrimaryLayuiButtonStyle}"
                                                        Command="{Binding BindingContext.ClaimAssignmentClickCommand,Source={x:Reference cpg}}"
                                                        CommandParameter="{Binding .}"
                                                        android:Button.UseDefaultShadow="True" 
                                                        android:Button.UseDefaultPadding="True"/>
                                            </StackLayout>


                                        </StackLayout>
                                        <Frame.Triggers>
                                            <DataTrigger TargetType="Frame" Binding="{Binding ISURGQMINSP}" Value="1">
                                                <Setter Property="BackgroundColor" Value="#FF8585"/>
                                            </DataTrigger>
                                        </Frame.Triggers>
                                    </Frame>
                                </ContentView>
                            </ViewCell>
                        </DataTemplate>
                    </ListView.ItemTemplate>
                </ListView>
            </StackLayout>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

2、界面后端代码

namespace ErpApp.Views.QMSamping
{
	[XamlCompilation(XamlCompilationOptions.Compile)]
	public partial class QMSampAssignmentPage : ContentPage
    {
		public QMSampAssignmentPage(BsUserList bsUserList)
		{
			InitializeComponent ();
			this.BindingContext = new QMSampAssignmentViewModel(bsUserList,this);
        }
	}
}

3、ViewModel

using AppUntils;
using EamApp.ViewModels;
using Newtonsoft.Json;
using StrongModel;
using StrongModel.Erp;
using StrongModel.Erp.InspectionModule;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using Xamarin.Forms;


namespace ErpApp.Views.QMSamping.ViewModel
{
    public class QMSampAssignmentViewModel : BaseViewModel
    {
        #region 属性

        public BsUserList user;

        public QMSampAssignmentPage page;




        /// <summary>
        /// 原数据
        /// </summary>
        private List<QMSampingListItem> CopyData =new List<QMSampingListItem>();


        private List<QMSampingListItem> _QmSampListItemsSource =new List<QMSampingListItem>();

        public List<QMSampingListItem> QmSampListItemsSource
        {
            get { return _QmSampListItemsSource; }
            set
            {
                _QmSampListItemsSource = value;
                OnPropertyChanged();
            }
        }




        #endregion





        /// <summary>
        /// 领取任务
        /// </summary>
        public ICommand ClaimAssignmentClickCommand { get; }



        public QMSampAssignmentViewModel(BsUserList user, QMSampAssignmentPage page)
        {
            this.user = user;
            this.page = page;


            ClaimAssignmentClickCommand = new Command<QMSampingListItem>(async (item) => await BtnClaimAssignmentClick(item));
        }

        


        /// <summary>
        /// 领取任务
        /// </summary>
        /// <returns></returns>
        public async Task BtnClaimAssignmentClick(QMSampingListItem item) {
            if (!XaApp.App.IsNetAvailable)
                await page.DisplayAlert("错误", "无网络连接", "确定");

            try
            {
                //var cell = ((sender as VisualElement).Parent.Parent.Parent.Parent.Parent as ViewCell).BindingContext as QMSampingListItem;
                //if (cell.BASIC_BILLSTATUS_ID == "1003")
                //{
                //    await this.DisplayAlert("温馨提示", "该单据已提交，禁止重复提交，请刷新数据！", "确定");
                //    return;
                //}
                QmSampingAssignmentModel model = new QmSampingAssignmentModel();


            }
            catch (Exception ex)
            {
                await page.DisplayAlert("任务领取失败", ex.Message, "确定");
            }
        }






    }
}