Question

我想在我的ListView中每页设置4个项目，我总共有5个项目，我的代码工作正常，但是当我执行代码时，我总是得到5个项目而不是4个项目：

    ObservableCollection<NvBarberry.Models.One_searchs> customers = new ObservableCollection<NvBarberry.Models.One_searchs>();
        ObservableCollection<NvBarberry.Models.One_searchs> filtered = new ObservableCollection<NvBarberry.Models.One_searchs>();
        int currentPageIndex = 0;
        int itemPerPage = 4;
        int totalPage = 0; 


private void Page_Loaded(object sender, RoutedEventArgs e)
        {
            getLocalsList();
        }

 private void ShowCurrentPageIndex()
        {
            this.tbCurrentPage.Text = (currentPageIndex + 1).ToString();
            if (Convert.ToInt32(tbCurrentPage.Text.ToString()) == totalPage)
            {
                this.tbNextPage.Text = "";
            }
            else
            {
                this.tbNextPage.Text = (currentPageIndex + 2).ToString();
            }
            NextBorder.Opacity = 0.5;
        }

        void Filter()
        {
            ObservableCollection<NvBarberry.Models.One_searchs> filtered = new ObservableCollection<NvBarberry.Models.One_searchs>();
            foreach (NvBarberry.Models.One_searchs item in customers)
            {
                int index = customers.IndexOf(item);

                if (index >= itemPerPage * currentPageIndex && index < itemPerPage * (currentPageIndex + 1))
                {
                    filtered.Add(item);
                }
            }
            this.listme.DataContext = filtered;
        }

        private void btnFirst_Click(object sender, RoutedEventArgs e)
        {
            // Display the first page 
            if (currentPageIndex != 0)
            {
                currentPageIndex = 0;
                Filter();
            }
            ShowCurrentPageIndex();
        }

        private void btnPrev_Click(object sender, RoutedEventArgs e)
        {
            // Display previous page 
            if (currentPageIndex > 0)
            {
                currentPageIndex--;
                Filter();
            }
            ShowCurrentPageIndex();
        }

        private void btnNext_Click(object sender, RoutedEventArgs e)
        {
            // Display next page 
            if (currentPageIndex < totalPage - 1)
            {
                currentPageIndex++;
                Filter();
            }
            ShowCurrentPageIndex();
        }

        private void btnLast_Click(object sender, RoutedEventArgs e)
        {
            // Display the last page 
            if (currentPageIndex != totalPage - 1)
            {
                currentPageIndex = totalPage - 1;
                Filter();
            }
            ShowCurrentPageIndex();
        }

  private async void getLocalsList()
        {
            try
            {
               string UriString2 = "MyWebService";
                  var http = new HttpClient();
            http.MaxResponseContentBufferSize = Int32.MaxValue;
            var response = await http.GetStringAsync(UriString2);
            var rootObject1 = JsonConvert.DeserializeObject<Nv.Models.RootObject>(response);
                    listme.ItemsSource = rootObject1.one_searchs;
                    int itemcount = 5;
                    // Calculate the total pages 
                    totalPage = itemcount / itemPerPage;
                    if (itemcount % itemPerPage != 0)
                    {
                        totalPage += 1;
                    }


                    Filter();
                    ShowCurrentPageIndex();

            }
            catch (Exception e)
            {
                e.Message.ToString();

            }

这是我的xaml代码：

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <Grid.RowDefinitions>
        <RowDefinition Height="*"></RowDefinition>
        <RowDefinition Height="100"></RowDefinition>
    </Grid.RowDefinitions>
    <Grid Grid.Row="0">
        <ListView x:Name="listme" >
            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding ID}"></TextBlock>
                        <TextBlock Text="{Binding Name}"></TextBlock>
                        <TextBlock Text="{Binding Age}"></TextBlock>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Grid>

    <Grid Grid.Row="2" VerticalAlignment="Center" HorizontalAlignment="Center">
        <StackPanel Orientation="Horizontal">

              <Button Height="50" HorizontalAlignment="Left"  Name="btnFirst" 
    VerticalAlignment="Bottom" Width="75" Click="btnFirst_Click" Background="Transparent">
                  <Button.Content>
                    <TextBlock Text="&#xE7A7;" FontFamily="Segoe MDL2 Assets" FontSize="25"/>
                  </Button.Content>
            </Button>
            <Button Height="50" HorizontalAlignment="Left" Name="btnPrev" Background="Transparent"
    VerticalAlignment="Bottom" Click="btnPrev_Click">
                <Button.Content>
                    <TextBlock Text="&#xE0A6;" FontFamily="Segoe MDL2 Assets" FontSize="25"/>
                </Button.Content>
            </Button>
            <Border Name="CurrentBorder" Height="50" Width="50" Background="Purple">
                <TextBlock Name="tbCurrentPage" Height="50" Width="50"></TextBlock>
            </Border>
            <Border Name="NextBorder" Height="50" Width="50" Background="Purple">
                <TextBlock Name="tbNextPage" Height="50" Width="50"></TextBlock>
            </Border>
            <Button Height="50" Name="btnNext" Background="Transparent" 
    VerticalAlignment="Bottom" Click="btnNext_Click">
                <Button.Content>
                    <TextBlock Text="&#xE0AB;" FontFamily="Segoe MDL2 Assets" FontSize="25"/>
                </Button.Content>
            </Button>
            <Button Height="50" HorizontalAlignment="Right" Name="btnLast" Background="Transparent"
    VerticalAlignment="Bottom" Click="btnLast_Click">
                <Button.Content>
                    <TextBlock Text="&#xE7A6;" FontFamily="Segoe MDL2 Assets" FontSize="25"/>
                </Button.Content>
            </Button>
        </StackPanel>
    </Grid>
</Grid>

我遇到的问题是每页只设置4个项目，而不是将它们全部放在我的ListView中的一个页面中，我用我的代码获取，我已将“itemPerPage”变量设置为4但是我总是遇到同样的问题所以，请问我如何更正我的代码，在ListView中每页只放4个项目谢谢你的帮助

Answer 1

索引是0基本值而不是1，并且您在if条件中使用＆gt; = 。只需删除=，您将在第一页上获得4个项目，在第二页上获得8个项目。

int index = customers.IndexOf(item);
if (index > itemPerPage * currentPageIndex && index < itemPerPage * (currentPageIndex + 1))
{
    filtered.Add(item);
}
else { break; }//all items are added no need to traverse all the list.

<强>更新

  int index = 0;
  foreach (NvBarberry.Models.One_searchs item in customers)
        {
            if (index > itemPerPage * currentPageIndex && index < itemPerPage * (currentPageIndex + 1))
            {
                filtered.Add(item);
            } else {break; }
            index++;
        }

更新2

  private async void getLocalsList()
    {
        try
        {
           string UriString2 = "MyWebService";
              var http = new HttpClient();
        http.MaxResponseContentBufferSize = Int32.MaxValue;
        var response = await http.GetStringAsync(UriString2);
        var rootObject1 = JsonConvert.DeserializeObject<Nv.Models.RootObject>(response);
                ///No need, as data will be assigned filter mehtod  listme.ItemsSource = rootObject1.one_searchs;
                int itemcount = 5;
                // Calculate the total pages 
                totalPage = itemcount / itemPerPage;
                if (itemcount % itemPerPage != 0)
                {
                    totalPage += 1;
                }

                currentPageIndex = 1
                Filter();
                ShowCurrentPageIndex();

        }
        catch (Exception e)
        {
            e.Message.ToString();

        }

在通用应用程序的ListView中限制每页4项

1 个答案: