Added possibility to add an item when no item is found (Blazored#215)

timbze · Mar 22, 2021 · 12991c0 · 12991c0
1 parent af77dd8
commit 12991c0
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Showing 5 changed files with 137 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -71,6 +71,9 @@ of `Person` but when a `Person` was selected you wanted the control to bind to a
 a `ConvertMethod` The convert method will be invoked by the control when a selection is made and will be passed the type selected. The method will need to handle the conversion
 and return the new type.
 
+If you want to allow adding an item based on the search when no items have been found, you can achieve this by providing the `AddItemOnEmptyResultMethod` as a parameter.
+This method will make the `NotFoundTemplate` selectable the same way a item would normally be, and will be invoked when the user selects the `NotFoundTemplate`.
+This method passes the `SearchText` and expects a new item to be returned.
 
 ### Local Data Example
 ```cs

diff --git a/samples/BlazorServer/Pages/Index.razor b/samples/BlazorServer/Pages/Index.razor
@@ -150,8 +150,44 @@
     {
         <p>@person.Firstname @person.Lastname</p>
     }
+    <hr />
 }
 
+<h1>Blazored Typeahead - Multi-select - Adding items on empty search result</h1>
+
+<BlazoredTypeahead SearchMethod="GetPeopleLocal"
+                   @bind-Values="SelectedPeopleWithNotFoundTemplate"
+                   Disabled="IsDisabledMulti"
+                   EnableDropDown="true"
+                   MinimumLength="2"
+                   AddItemOnEmptyResultMethod="ItemAddedMethod"
+                   placeholder="Search by first name...">
+    <SelectedTemplate Context="person">
+        @person.Firstname
+    </SelectedTemplate>
+    <HelpTemplate>
+        Please enter a minimum of 2 characters to perform a search.
+    </HelpTemplate>
+    <NotFoundTemplate Context="searchText">
+        Add "@searchText" as a new user <br />
+        The newly added user will be selected after being added.
+    </NotFoundTemplate>
+    <ResultTemplate Context="person">
+        @person.Firstname @person.Lastname (Id: @person.Id)
+    </ResultTemplate>
+</BlazoredTypeahead>
+<button class="btn btn-primary" style="margin-top: 20px;" @onclick="@(() => IsDisabledMulti = !IsDisabledMulti)">@(IsDisabledMulti ? "Enable" : "Disable")</button>
+<hr />
+
+@if (SelectedPeopleWithNotFoundTemplate != null)
+{
+    <p>Selected People:</p>
+    foreach (var person in SelectedPeopleWithNotFoundTemplate)
+    {
+        <p>@person.Firstname @person.Lastname</p>
+    }
+    <hr />
+}
 
 @code {
 
@@ -164,6 +200,7 @@
     private Person SelectedPersonNull;
     private int? SelectedPersonId;
     private IList<Person> SelectedPeople;
+    private IList<Person> SelectedPeopleWithNotFoundTemplate;
     private FormExample FormModel = new FormExample();
 
     protected override void OnInitialized()
@@ -242,4 +279,14 @@
     {
         return People.FirstOrDefault(p => p.Id == id);
     }
+
+    private readonly Random _random = new Random();
+    private Task<Person> ItemAddedMethod(string searchText)
+    {
+        var randomPerson = People[_random.Next(People.Count - 1)];
+        var newPerson = new Person(_random.Next(1000, int.MaxValue), searchText, randomPerson.Lastname, _random.Next(10, 70), randomPerson.Location);
+        People.Add(newPerson);
+        return Task.FromResult(newPerson);
+    }
+
 }
diff --git a/samples/BlazorWebAssembly/Pages/Index.razor b/samples/BlazorWebAssembly/Pages/Index.razor
@@ -146,10 +146,45 @@
     {
         <p>@person.Firstname @person.Lastname</p>
     }
+    <hr />
 }
 
+<h1>Blazored Typeahead - Multi-select - Adding items on empty search result</h1>
+
+<BlazoredTypeahead SearchMethod="GetPeopleLocal"
+                   @bind-Values="SelectedPeopleWithNotFoundTemplate"
+                   Disabled="IsDisabledMulti"
+                   EnableDropDown="true"
+                   MinimumLength="2"
+                   AddItemOnEmptyResultMethod="ItemAddedMethod"
+                   placeholder="Search by first name...">
+    <SelectedTemplate Context="person">
+        @person.Firstname
+    </SelectedTemplate>
+    <HelpTemplate>
+        Please enter a minimum of 2 characters to perform a search.
+    </HelpTemplate>
+    <NotFoundTemplate Context="searchText">
+        Add "@searchText" as a new user <br />
+        The newly added user will be selected after being added.
+    </NotFoundTemplate>
+    <ResultTemplate Context="person">
+        @person.Firstname @person.Lastname (Id: @person.Id)
+    </ResultTemplate>
+</BlazoredTypeahead>
+<button class="btn btn-primary" style="margin-top: 20px;" @onclick="@(() => IsDisabledMulti = !IsDisabledMulti)">@(IsDisabledMulti ? "Enable" : "Disable")</button>
 <hr />
 
+@if (SelectedPeopleWithNotFoundTemplate != null)
+{
+    <p>Selected People:</p>
+    foreach (var person in SelectedPeopleWithNotFoundTemplate)
+    {
+        <p>@person.Firstname @person.Lastname</p>
+    }
+    <hr />
+}
+
 <h1>Blazored Typeahead - Header and footer templates</h1>
 
 <BlazoredTypeahead SearchMethod="GetPeopleLocal"
@@ -187,6 +222,7 @@
     private Person SelectedPersonNull;
     private int? SelectedPersonId;
     private IList<Person> SelectedPeople;
+    private IList<Person> SelectedPeopleWithNotFoundTemplate;
     private FormExample FormModel = new FormExample();
     private BlazoredTypeahead<Person, Person> LocalBlazoredTypeahead;
 
@@ -266,4 +302,13 @@
     {
         return People.FirstOrDefault(p => p.Id == id);
     }
+
+    private readonly Random _random = new Random();
+    private Task<Person> ItemAddedMethod(string searchText)
+    {
+        var randomPerson = People[_random.Next(People.Count - 1)];
+        var newPerson = new Person(_random.Next(1000, int.MaxValue), searchText, randomPerson.Lastname, _random.Next(10, 70), randomPerson.Location);
+        People.Add(newPerson);
+        return Task.FromResult(newPerson);
+    }
 }
diff --git a/src/Blazored.Typeahead/BlazoredTypeahead.razor b/src/Blazored.Typeahead/BlazoredTypeahead.razor
@@ -185,9 +185,19 @@
 
             @if (NotFoundTemplate != null)
             {
-                <div class="blazored-typeahead__notfound">
-                    @NotFoundTemplate
-                </div>
+                @if (AddItemOnEmptyResultMethod != null)
+                {
+                    <div class="blazored-typeahead__result @GetSelectedSuggestionClass(0)"
+                         @onclick="@SelectNotFoundPlaceholder">
+                        @NotFoundTemplate(SearchText)
+                    </div>
+                }
+                else
+                {
+                    <div class="blazored-typeahead__notfound">
+                        @NotFoundTemplate(SearchText)
+                    </div>    
+                }
             }
             else
             {

diff --git a/src/Blazored.Typeahead/BlazoredTypeahead.razor.cs b/src/Blazored.Typeahead/BlazoredTypeahead.razor.cs
@@ -4,6 +4,7 @@
 using Microsoft.JSInterop;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Threading.Tasks;
@@ -38,8 +39,9 @@ public partial class BlazoredTypeahead<TItem, TValue> : ComponentBase, IDisposab
 
         [Parameter] public Func<string, Task<IEnumerable<TItem>>> SearchMethod { get; set; }
         [Parameter] public Func<TItem, TValue> ConvertMethod { get; set; }
+        [Parameter] public Func<string, Task<TItem>> AddItemOnEmptyResultMethod { get; set; }
 
-        [Parameter] public RenderFragment NotFoundTemplate { get; set; }
+        [Parameter] public RenderFragment<string> NotFoundTemplate { get; set; }
         [Parameter] public RenderFragment HelpTemplate { get; set; }
         [Parameter] public RenderFragment<TItem> ResultTemplate { get; set; }
         [Parameter] public RenderFragment<TValue> SelectedTemplate { get; set; }
@@ -275,6 +277,10 @@ private async Task HandleKeyup(KeyboardEventArgs args)
             {
                 await SelectTheFirstAndOnlySuggestion();
             }
+            else if (args.Key == "Enter" && ShowNotFound() && AddItemOnEmptyResultMethod != null)
+            {
+                await SelectNotFoundPlaceholder();
+            }
             else if (args.Key == "Enter" && SelectedIndex >= 0 && SelectedIndex < Suggestions.Count())
             {
                 await SelectResult(Suggestions[SelectedIndex]);
@@ -372,6 +378,13 @@ private string GetSelectedSuggestionClass(TItem item, int index)
             return Equals(value, Value) ? resultClass : string.Empty;
         }
 
+        private string GetSelectedSuggestionClass(int index)
+        {
+            const string resultClass = "blazored-typeahead__active-item";
+
+            return index == SelectedIndex ? resultClass : string.Empty;
+        }
+
         private async void Search(Object source, ElapsedEventArgs e)
         {
             if (_searchText.Length < MinimumLength)
@@ -426,6 +439,21 @@ private async Task SelectResult(TItem item)
             Initialize();
         }
 
+        private async Task SelectNotFoundPlaceholder()
+        {
+            Debug.Assert(AddItemOnEmptyResultMethod != null);
+            try
+            {
+                // Potentially dangerous code
+                var item = await AddItemOnEmptyResultMethod(SearchText);
+                await SelectResult(item);
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine(e.Message);
+            }
+        }
+
         private bool ShouldShowHelpTemplate()
         {
             return SearchText.Length > 0 &&