C# 从json延迟加载gridview

我在gridview中有一个延迟加载，它的数据来自JSON

JSON示例：

{
    "error": false,
    "total_data": 32,
    "data_per_page": "16",
    "current_page": 1,
    "total_page": 2,
    "current_total": 16,
    "data": [
        {
            "id": "2613",
            "judul": "Kamus ID EN",
            "slug": "kamus-id-en",
            "cover": "https://mhnkp2.com/src/umum/cover/kamus_ID_EN-thumb.jpg",
            "path": "https://mhnkp2.com/school/dl/dodl/2613",
            "ukuran": "3504835",
            "formated_size": "3.34 MB",
            "fname": "kamus_ID_EN.pdf",
            "publish": "1",
            "urgent": "400",
            "kelas": "0",
            "nama_kelas": "Umum"
        },

XAML：

代码：

ObservableCollection数据源=新的ObservableCollection（）；
整数偏移=0；
已加载私有void主网格（对象发送方、路由目标）
{
itemGridView.ItemsSource=数据源；
肿瘤（1）；
} 
公务舱布库
{
公共字符串Judul{get；set；}
}
专用异步void umm（整数偏移）
{
urlPath=”https://mhnkp2.com/school/api-v3/fetch/umum";
var httpClient=newhttpclient（newhttpclienthandler（））；
var值=新列表
{
新的KeyValuePair（“halaman”，offset.ToString（）），
新的KeyValuePair（“限制”、“16”），
新的KeyValuePair（“SCH-API-KEY”、“SCH_KEnaBiDeplebt”）
};
var response=wait httpClient.PostAsync（urlPath，新表单URLEncodedcontent（值））；
response.EnsureSuccessStatusCode（）；
string jsonText=await response.Content.ReadAsStringAsync（）；
尝试
{
double total=groupObject1[“total_data”]。GetNumber（）；
double pages=groupObject1[“总页数”]。GetNumber（）；
double page=groupObject1[“当前页面”]。GetNumber（）；
Buku文件=新的Buku（）；
file.PageNo=Convert.ToInt32（第页）；
file.Pages=Convert.ToInt32（页）；
file.Total=Convert.ToInt32（总计）；
JsonArray jsonData1=jsonObject[“数据”].GetArray（）；
foreach（jsonData1中的JsonValue groupValue1）
{
JsonObject groupObject2=groupValue1.GetObject（）；
string title=groupObject2[“judul”].GetString（）；
Buku file1=新的Buku（）；
file1.Judul=标题；
datasource.Add（file1）；
}
itemGridView.ItemsSource=数据源；
}
}
已加载私有void itemGridView_（对象发送方，RoutedEventArgs e）
{
ScrollViewer=GetScrollViewer（this.itemGridView）；
viewer.ViewChanged+=viewer\u ViewChanged；
}
私有void Viewer_ViewChanged（对象发送器，ScrollViewerViewChangedEventArgs e）
{
ScrollViewer视图=（ScrollViewer）发送方；
双进度=view.VerticalOffset/view.ScrollableHeight；
//Debug.WriteLine（进度）；
如果（进度>0.7&&！incall&&！endoflist）
{
incall=true；
busyindicator.IsActive=true；
Umum（++偏移量）；
}
}
公共静态ScrollViewer GetScrollViewer（DependencyObject depObj）
{
如果（depObj是ScrollViewer），则返回depObj作为ScrollViewer；
for（int i=0；i

我有一个问题，gridview应该在第1页和第2页显示数据，但在gridview中，第2页显示的数据是第1页数据的重复，如下所示： 如何修复它

注:

• 页面使用“offset”参数

• 页面限制是JSON中的“总页面”

---

您只需将偏移值传递给加载的

MainGrid\u

，然后将偏移0设置为1

ObservableCollection<Buku> datasource = new ObservableCollection<Buku>();
int offset = 1; // set offset zero to one 
        private void MainGrid_Loaded(object sender, RoutedEventArgs e)
                    {
                        itemGridView.ItemsSource = datasource;
                        Umum(offset); // just change 1 to offset 
                    } 
    public class Buku
        {
            public string Judul { get; set; }
        }

            private async void Umum(int offset)
            {
                urlPath = "mhnkp2.com/school/api-v3/fetch/ktsp2006/kelas/1";
                var httpClient = new HttpClient(new HttpClientHandler());
                var values = new List<KeyValuePair<string, string>>
                {
                    new KeyValuePair<string, string>("halaman", offset.ToString()),
                    new KeyValuePair<string, string>("limit", "16"),
                    new KeyValuePair<string, string>("SCH-API-KEY", "SCH_KEnaBiDeplebt")
                };

                var response = await httpClient.PostAsync(urlPath, new FormUrlEncodedContent(values));
                response.EnsureSuccessStatusCode();
                string jsonText = await response.Content.ReadAsStringAsync();
                try
                {
                    double total = groupObject1["total_data"].GetNumber();
                    double pages = groupObject1["total_page"].GetNumber();
                    double page = groupObject1["current_page"].GetNumber();

                    Buku file = new Buku();
                    file.PageNo = Convert.ToInt32(page);
                    file.Pages = Convert.ToInt32(pages);
                    file.Total = Convert.ToInt32(total);
                    JsonArray jsonData1 = jsonObject["data"].GetArray();
                    foreach (JsonValue groupValue1 in jsonData1)
                    {
                        JsonObject groupObject2 = groupValue1.GetObject();
                        string title = groupObject2["judul"].GetString();

                        Buku file1 = new Buku();
                        file1.Judul = title;
                        datasource.Add(file1);
                    }
                    itemGridView.ItemsSource = datasource;
                }
            }

            private void itemGridView_Loaded(object sender, RoutedEventArgs e)
                    {
                        ScrollViewer viewer = GetScrollViewer(this.itemGridView);
                        viewer.ViewChanged += Viewer_ViewChanged;
                    }

                    private void Viewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
                    {
                        ScrollViewer view = (ScrollViewer)sender;
                        double progress = view.VerticalOffset / view.ScrollableHeight;
                        //Debug.WriteLine(progress);
                        if (progress > 0.7 && !incall && !endoflist)
                        {
                            incall = true;
                            busyindicator.IsActive = true;
                            Umum(offset++);
                        }
                    }

                    public static ScrollViewer GetScrollViewer(DependencyObject depObj)
                    {
                        if (depObj is ScrollViewer) return depObj as ScrollViewer;

                        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                        {
                            var child = VisualTreeHelper.GetChild(depObj, i);
                            var result = GetScrollViewer(child);
                            if (result != null) return result;
                        }
                        return null;
                    }

ObservableCollection数据源=新的ObservableCollection（）；
int offset=1；//将偏移量0设置为1
已加载私有void主网格（对象发送方、路由目标）
{
itemGridView.ItemsSource=数据源；
Umum（offset）；//只需将1更改为offset
} 
公务舱布库
{
公共字符串Judul{get；set；}
}
专用异步void umm（整数偏移）
{
urlPath=“mhnkp2.com/school/api-v3/fetch/ktsp2006/kelas/1”；
var httpClient=newhttpclient（newhttpclienthandler（））；
var值=新列表
{
新的KeyValuePair（“halaman”，offset.ToString（）），
新的KeyValuePair（“限制”、“16”），
新的KeyValuePair（“SCH-API-KEY”、“SCH_KEnaBiDeplebt”）
};
var response=wait httpClient.PostAsync（urlPath，新表单URLEncodedcontent（值））；
response.EnsureSuccessStatusCode（）；
string jsonText=await response.Content.ReadAsStringAsync（）；
尝试
{
double total=groupObject1[“total_data”]。GetNumber（）；
double pages=groupObject1[“总页数”]。GetNumber（）；
double page=groupObject1[“当前页面”]。GetNumber（）；
Buku文件=新的Buku（）；
file.PageNo=Convert.ToInt32（第页）；
file.Pages=Convert.ToInt32
ObservableCollection<Buku> datasource = new ObservableCollection<Buku>();
int offset = 0;
        private void MainGrid_Loaded(object sender, RoutedEventArgs e)
                    {
                        itemGridView.ItemsSource = datasource;
                        Umum(1);
                    } 
    public class Buku
        {
            public string Judul { get; set; }
        }

            private async void Umum(int offset)
            {
                urlPath = "https://mhnkp2.com/school/api-v3/fetch/umum";
                var httpClient = new HttpClient(new HttpClientHandler());
                var values = new List<KeyValuePair<string, string>>
                {
                    new KeyValuePair<string, string>("halaman", offset.ToString()),
                    new KeyValuePair<string, string>("limit", "16"),
                    new KeyValuePair<string, string>("SCH-API-KEY", "SCH_KEnaBiDeplebt")
                };

                var response = await httpClient.PostAsync(urlPath, new FormUrlEncodedContent(values));
                response.EnsureSuccessStatusCode();
                string jsonText = await response.Content.ReadAsStringAsync();
                try
                {
                    double total = groupObject1["total_data"].GetNumber();
                    double pages = groupObject1["total_page"].GetNumber();
                    double page = groupObject1["current_page"].GetNumber();

                    Buku file = new Buku();
                    file.PageNo = Convert.ToInt32(page);
                    file.Pages = Convert.ToInt32(pages);
                    file.Total = Convert.ToInt32(total);
                    JsonArray jsonData1 = jsonObject["data"].GetArray();
                    foreach (JsonValue groupValue1 in jsonData1)
                    {
                        JsonObject groupObject2 = groupValue1.GetObject();
                        string title = groupObject2["judul"].GetString();

                        Buku file1 = new Buku();
                        file1.Judul = title;
                        datasource.Add(file1);
                    }
                    itemGridView.ItemsSource = datasource;
                }
            }

            private void itemGridView_Loaded(object sender, RoutedEventArgs e)
                    {
                        ScrollViewer viewer = GetScrollViewer(this.itemGridView);
                        viewer.ViewChanged += Viewer_ViewChanged;
                    }

                    private void Viewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
                    {
                        ScrollViewer view = (ScrollViewer)sender;
                        double progress = view.VerticalOffset / view.ScrollableHeight;
                        //Debug.WriteLine(progress);
                        if (progress > 0.7 && !incall && !endoflist)
                        {
                            incall = true;
                            busyindicator.IsActive = true;
                            Umum(++offset);
                        }
                    }

                    public static ScrollViewer GetScrollViewer(DependencyObject depObj)
                    {
                        if (depObj is ScrollViewer) return depObj as ScrollViewer;

                        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                        {
                            var child = VisualTreeHelper.GetChild(depObj, i);
                            var result = GetScrollViewer(child);
                            if (result != null) return result;
                        }
                        return null;
                    }

ObservableCollection<Buku> datasource = new ObservableCollection<Buku>();
int offset = 1; // set offset zero to one 
        private void MainGrid_Loaded(object sender, RoutedEventArgs e)
                    {
                        itemGridView.ItemsSource = datasource;
                        Umum(offset); // just change 1 to offset 
                    } 
    public class Buku
        {
            public string Judul { get; set; }
        }

            private async void Umum(int offset)
            {
                urlPath = "mhnkp2.com/school/api-v3/fetch/ktsp2006/kelas/1";
                var httpClient = new HttpClient(new HttpClientHandler());
                var values = new List<KeyValuePair<string, string>>
                {
                    new KeyValuePair<string, string>("halaman", offset.ToString()),
                    new KeyValuePair<string, string>("limit", "16"),
                    new KeyValuePair<string, string>("SCH-API-KEY", "SCH_KEnaBiDeplebt")
                };

                var response = await httpClient.PostAsync(urlPath, new FormUrlEncodedContent(values));
                response.EnsureSuccessStatusCode();
                string jsonText = await response.Content.ReadAsStringAsync();
                try
                {
                    double total = groupObject1["total_data"].GetNumber();
                    double pages = groupObject1["total_page"].GetNumber();
                    double page = groupObject1["current_page"].GetNumber();

                    Buku file = new Buku();
                    file.PageNo = Convert.ToInt32(page);
                    file.Pages = Convert.ToInt32(pages);
                    file.Total = Convert.ToInt32(total);
                    JsonArray jsonData1 = jsonObject["data"].GetArray();
                    foreach (JsonValue groupValue1 in jsonData1)
                    {
                        JsonObject groupObject2 = groupValue1.GetObject();
                        string title = groupObject2["judul"].GetString();

                        Buku file1 = new Buku();
                        file1.Judul = title;
                        datasource.Add(file1);
                    }
                    itemGridView.ItemsSource = datasource;
                }
            }

            private void itemGridView_Loaded(object sender, RoutedEventArgs e)
                    {
                        ScrollViewer viewer = GetScrollViewer(this.itemGridView);
                        viewer.ViewChanged += Viewer_ViewChanged;
                    }

                    private void Viewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
                    {
                        ScrollViewer view = (ScrollViewer)sender;
                        double progress = view.VerticalOffset / view.ScrollableHeight;
                        //Debug.WriteLine(progress);
                        if (progress > 0.7 && !incall && !endoflist)
                        {
                            incall = true;
                            busyindicator.IsActive = true;
                            Umum(offset++);
                        }
                    }

                    public static ScrollViewer GetScrollViewer(DependencyObject depObj)
                    {
                        if (depObj is ScrollViewer) return depObj as ScrollViewer;

                        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                        {
                            var child = VisualTreeHelper.GetChild(depObj, i);
                            var result = GetScrollViewer(child);
                            if (result != null) return result;
                        }
                        return null;
                    }