Trial - boosting prospect grid loading performance

FoodsharingSiegen.Server/Pages/ProspectsAll.razor.cs

@@ -5,6 +5,7 @@ using FoodsharingSiegen.Contracts.Helper;
 using FoodsharingSiegen.Contracts.Model;
 using FoodsharingSiegen.Server.Data.Service;
 using FoodsharingSiegen.Server.Dialogs;
+using FoodsharingSiegen.Shared.Helper;
 using Microsoft.AspNetCore.Components;
 
 namespace FoodsharingSiegen.Server.Pages
@@ -37,7 +38,17 @@ namespace FoodsharingSiegen.Server.Pages
         /// <summary>
         ///     Gets or sets the value of the prospect list (ab)
         /// </summary>
-        private List<Prospect>? ProspectList { get; set; }
+        private List<Prospect> ProspectList { get; set; } = [];
+
+        private bool IsLoadingProspects { get; set; }
+
+        private bool IsLoadingMoreProspects { get; set; }
+
+        private bool HasMoreProspects { get; set; }
+
+        private int CurrentPageSize { get; set; } = 50;
+
+        private int CurrentSkip { get; set; }
 
         private ProspectSortOption CurrentSort { get; set; } = ProspectSortOption.NameAscending;
 
@@ -71,6 +82,9 @@ namespace FoodsharingSiegen.Server.Pages
         {
             Filter = arg;
             await LocalStorageService.SetItem(StorageKeys.ProspectFilter, Filter);
+            CurrentSkip = 0;
+            ProspectList = [];
+            await LoadProspects();
         }
 
         #endregion
@@ -80,17 +94,83 @@ namespace FoodsharingSiegen.Server.Pages
         /// <summary>
         ///     Loads the prospects (a. beging, 11.04.2022)
         /// </summary>
+        private bool HasActiveFilter()
+        {
+            return !string.IsNullOrWhiteSpace(Filter.Text)
+                || Filter.WithoutStepInBriefing
+                || Filter.WithoutIdCheck
+                || Filter.DeletedOnly
+                || Filter.IdCheckPossible
+                || Filter.NoActivity
+                || Filter.RecentActivity;
+        }
+
         private async Task LoadProspects()
         {
-            var parameter = new GetProspectsParameter
-            {
-                IncludeDeleted = true
-            };
-            
-            var prospectsR = await ProspectService.GetProspectsAsync(parameter);
-            if (prospectsR.Success) ProspectList = prospectsR.Data;
+            if (IsLoadingProspects || IsLoadingMoreProspects) return;
 
-            await InvokeAsync(StateHasChanged);
+            try
+            {
+                if (CurrentSkip == 0)
+                {
+                    IsLoadingProspects = true;
+                }
+                else
+                {
+                    IsLoadingMoreProspects = true;
+                }
+
+                await InvokeAsync(StateHasChanged);
+
+                while (true)
+                {
+                    var parameter = new GetProspectsParameter
+                    {
+                        Skip = CurrentSkip,
+                        Take = CurrentPageSize,
+                        IncludeDeleted = true
+                    };
+
+                    var prospectsR = await ProspectService.GetProspectsAsync(parameter);
+                    if (!prospectsR.Success)
+                    {
+                        break;
+                    }
+
+                    var loadedProspects = prospectsR.Data ?? [];
+                    if (CurrentSkip == 0)
+                    {
+                        ProspectList = loadedProspects;
+                    }
+                    else
+                    {
+                        ProspectList = [.. ProspectList, .. loadedProspects];
+                    }
+
+                    CurrentSkip += loadedProspects.Count;
+                    HasMoreProspects = loadedProspects.Count == CurrentPageSize;
+
+                    var filteredCount = ProspectList.ApplyFilter(Filter).Count;
+                    if (!HasActiveFilter() || filteredCount > 0 || !HasMoreProspects || loadedProspects.Count == 0)
+                    {
+                        break;
+                    }
+                }
+
+                await InvokeAsync(StateHasChanged);
+            }
+            finally
+            {
+                IsLoadingProspects = false;
+                IsLoadingMoreProspects = false;
+                await InvokeAsync(StateHasChanged);
+            }
+        }
+
+        private async Task LoadMoreProspects()
+        {
+            if (IsLoadingProspects || IsLoadingMoreProspects || !HasMoreProspects) return;
+            await LoadProspects();
         }
 
         #endregion