Add missing item.SetSelected call for multi select when pre-selection is provided (#240)

* Add missing Set Selected for multi select when pre-selection is provided via a parameter.

* Fix selection bug when virtualizing based on an ItemCollection.

* add UpdateSelectedStyles on clearing of search text

Author: radderz

CodeBeam.MudBlazor.Extensions/Components/ListExtended/MudListExtended.razor

@@ -32,7 +32,7 @@
                         {
                             <MudCheckBox CheckedIcon="@SelectAllCheckBoxIcon" Color="@Color" @bind-Checked="_allSelected" @onclick="() => SelectAllItems(_allSelected)" Dense="true" />
                         }
-                        <MudTextField @ref="_searchField" @bind-Value="@_searchString" Class="@ClassSearchBox" Placeholder="@SearchBoxPlaceholder" OnKeyDown="SearchBoxHandleKeyDown" OnKeyUp="@(() => UpdateSelectedStyles())" Immediate="true" Variant="Variant.Outlined" Margin="Margin.Dense"
+                        <MudTextField @ref="_searchField" @bind-Value="@_searchString" Class="@ClassSearchBox" Placeholder="@SearchBoxPlaceholder" OnKeyDown="SearchBoxHandleKeyDown" OnKeyUp="@(() => UpdateSelectedStyles())" OnClearButtonClick="@(() => UpdateSelectedStyles())" Immediate="true" Variant="Variant.Outlined" Margin="Margin.Dense"
                             Adornment="Adornment.End" AdornmentIcon="@Icons.Material.Filled.Search" AdornmentColor="Color" AutoFocus="@SearchBoxAutoFocus" Clearable="@SearchBoxClearable" />
                     </div>
                 </MudListSubheaderExtended>

CodeBeam.MudBlazor.Extensions/Components/ListExtended/MudListExtended.razor.cs

@@ -400,7 +400,6 @@ protected void HandleCentralValueCommander(string changedValueType, bool updateS
             else if (changedValueType == "MultiSelectionOff")
             {
                 SelectedValue = SelectedValues == null ? default(T) : SelectedValues.FirstOrDefault();
-                var items = CollectAllMudListItems(true);
                 SelectedValues = SelectedValue == null ? null : new HashSet<T>(_comparer) { SelectedValue };
                 UpdateSelectedItem();
             }
@@ -762,6 +761,11 @@ protected internal void Register(MudListItemExtended<T> item)
                 //SelectedItem = item;
                 //SelectedItemChanged.InvokeAsync(item);
             }
+
+            if (MultiSelection && SelectedValues != null && SelectedValues.Contains(item.Value))
+            {
+                item.SetSelected(true);
+            }
         }
 
         protected internal void Unregister(MudListItemExtended<T> item)
@@ -1068,7 +1072,11 @@ protected internal void UpdateSelectAllState()
                 {
                     _allSelected = false;
                 }
-                else if (CollectAllMudListItems(true).Count() == _selectedValues.Count)
+                else if (ItemCollection != null && ItemCollection.Count == _selectedValues.Count)
+                {
+                    _allSelected = true;
+                }
+                else if (ItemCollection == null && CollectAllMudListItems(true).Count() == _selectedValues.Count)
                 {
                     _allSelected = true;
                 }
@@ -1134,7 +1142,15 @@ protected void SelectAllItems(bool? deselect = false)
                 _allSelected = true;
             }
 
-            SelectedValues = items.Where(x => x.IsSelected).Select(y => y.Value).ToHashSet(_comparer);
+            if (ItemCollection != null)
+            {
+                SelectedValues = deselect == true ? Enumerable.Empty<T>() : ItemCollection.ToHashSet(_comparer);
+            }
+            else
+            {
+                SelectedValues = items.Where(x => x.IsSelected).Select(y => y.Value).ToHashSet(_comparer);
+            }
+
             if (MudSelectExtended != null)
             {
                 MudSelectExtended.BeginValidatePublic();