Initial commit

Chapter07/MyBlog/Components/RazorComponents/Alert.razor

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+<div class="@($"alert alert-{Style.ToString().ToLower()}")" role="alert">
+    @ChildContent
+</div>
+@code{
+    [Parameter]
+    public RenderFragment ChildContent { get; set; }      =@<b>This is a default value</b>;
+    [Parameter]
+    public AlertStyle Style { get; set; }
+    public enum AlertStyle
+    {
+        Primary,
+        Secondary,
+        Success,
+        Danger,
+        Warning,
+        Info,
+        Light,
+        Dark
+    }
+}

Chapter07/MyBlog/Components/RazorComponents/BlogNavigationLock.razor

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+@inject IJSRuntime JSRuntime
+@implements IDisposable
+
+<NavigationLock 
+    ConfirmExternalNavigation="@(CurrentEditContext.IsModified())"
+    OnBeforeInternalNavigation="OnBeforeInternalNavigation" />
+
+@code{
+    [CascadingParameter]
+    public required EditContext CurrentEditContext { get; set; }
+    public string InternalNavigationMessage { get; set; } = "You are about to loose changes, are you sure you want to navigate away?";
+
+    protected override Task OnInitializedAsync()
+    {
+        CurrentEditContext.OnFieldChanged += OnFieldChangedAsync;
+        return base.OnInitializedAsync();
+    }
+
+    private async void OnFieldChangedAsync(object? sender,FieldChangedEventArgs args)
+    {
+        await InvokeAsync(StateHasChanged);
+    }
+
+    private async Task OnBeforeInternalNavigation(LocationChangingContext context)
+    {
+        if (CurrentEditContext.IsModified())
+        {
+            var isConfirmed = await JSRuntime.InvokeAsync<bool>("confirm",
+                InternalNavigationMessage);
+
+            if (!isConfirmed)
+            {
+                context.PreventNavigation();
+            }
+        }
+    }
+
+    void IDisposable.Dispose()
+    {
+        CurrentEditContext.OnFieldChanged -= OnFieldChangedAsync;
+    }
+}

Chapter07/MyBlog/Components/RazorComponents/BootstrapFieldCssClassProvider.cs

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+using Microsoft.AspNetCore.Components.Forms;
+namespace Components;
+public class BootstrapFieldCssClassProvider : FieldCssClassProvider
+{
+    public override string GetFieldCssClass(EditContext editContext, in FieldIdentifier fieldIdentifier)
+    {
+        var isValid = !editContext.GetValidationMessages(fieldIdentifier).Any();
+        var isModified = editContext.IsModified(fieldIdentifier);
+        return (isModified, isValid) switch
+        {
+            (true, true) => "form-control modified is-valid",
+            (true, false) => "form-control modified is-invalid",
+            (false, true) => "form-control",
+            (false, false) => "form-control"
+        };
+    }
+}

Chapter07/MyBlog/Components/RazorComponents/CustomCssClassProvider.cs

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+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Forms;
+namespace Components;
+
+public class CustomCssClassProvider<ProviderType> : ComponentBase where ProviderType : FieldCssClassProvider, new()
+{
+    [CascadingParameter]
+    EditContext? CurrentEditContext { get; set; }
+    public ProviderType Provider { get; set; } = new ProviderType();
+    protected override void OnInitialized()
+    {
+        if (CurrentEditContext == null)
+        {
+            throw new InvalidOperationException($"{nameof(CustomCssClassProvider<ProviderType>)} requires a cascading parameter of type {nameof(EditContext)}. For example, you can use {nameof(CustomCssClassProvider<ProviderType>)} inside an EditForm.");
+        }
+        CurrentEditContext.SetFieldCssClassProvider
+         (Provider);
+    }
+}

Chapter07/MyBlog/Components/RazorComponents/InputTextAreaOnInput.cs

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+using System.Diagnostics.CodeAnalysis;
+using Microsoft.AspNetCore.Components.Rendering;
+namespace Microsoft.AspNetCore.Components.Forms;
+public class InputTextAreaOnInput :
+ InputBase<string?>
+{
+    protected override void BuildRenderTree(RenderTreeBuilder builder)
+    {
+        builder.OpenElement(0, "textarea");
+        builder.AddMultipleAttributes(1, AdditionalAttributes);
+        builder.AddAttribute(2, "class", CssClass);
+        builder.AddAttribute(3, "value", BindConverter.FormatValue(CurrentValue));
+        builder.AddAttribute(4, "oninput", EventCallback.Factory.CreateBinder<string?>(this, __value => CurrentValueAsString = __value, CurrentValueAsString));
+        builder.CloseElement();
+    }
+    protected override bool TryParseValueFromString(string? value, out string? result, [NotNullWhen(false)] out string? validationErrorMessage)
+    {
+        result = value;
+        validationErrorMessage = null;
+        return true;
+    }
+}

Chapter07/MyBlog/Components/RazorComponents/ItemList.razor

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+@typeparam ItemType
+@using System.Collections.Generic
+<h3>List</h3>
+<table>
+    <Virtualize Items="@Items" Context="item">
+        <tr>
+            <td>
+                <button class="btn btn-primary" @onclick="@(()=>                {SelectEvent.InvokeAsync(item); })">                  Select</button>
+            </td>
+            <td>@ItemTemplate(item)</td>
+            <td>
+                <button class="btn btn-danger" @onclick="@(()=>               {DeleteEvent.InvokeAsync(item);})">                 Delete</button>
+            </td>
+        </tr>
+    </Virtualize>
+</table>
+
+
+@code{
+    [Parameter]
+    public List<ItemType> Items { get; set; } = new List<ItemType>();
+    [Parameter, EditorRequired]
+    public required RenderFragment<ItemType> ItemTemplate { get; set; }
+    [Parameter]
+    public EventCallback<ItemType> DeleteEvent { get; set; }
+    [Parameter]
+    public EventCallback<ItemType> SelectEvent { get; set; }
+
+}