@using System.ComponentModel.DataAnnotations

@inject IJSRuntime js

<label><TelerikCheckBox @bind-Value="@EnableScrollWorkaround" /> Enable Workaround</label>

<TelerikGrid Data="@GridData"
             EditMode="@GridEditMode.Inline"
             OnAdd="@OnGridAdd"
             OnUpdate="@OnGridUpdate"
             OnCreate="@OnGridCreate"
             Width="700px"
             Height="400px"
             Class="grid-class">
    <GridToolBarTemplate>
        <GridCommandButton Command="Add">Add Item</GridCommandButton>
    </GridToolBarTemplate>
    <GridColumns>
        <GridColumn Field="@nameof(Product.Name)" Width="200px" Locked="true" />
        <GridColumn Field="@nameof(Product.Price)" Width="200px" />
        <GridColumn Field="@nameof(Product.Quantity)" Width="200px" />
        <GridCommandColumn Width="200px" Locked="true">
            <GridCommandButton Command="Edit">Edit</GridCommandButton>
            <GridCommandButton Command="Save" ShowInEdit="true">Save</GridCommandButton>
            <GridCommandButton Command="Cancel" ShowInEdit="true">Cancel</GridCommandButton>
        </GridCommandColumn>
    </GridColumns>
</TelerikGrid>

<script suppress-error="BL9992">

    function scrollGridToTop() {
        var gridContentArea = document.querySelector(".grid-class .k-grid-content");
        if (gridContentArea) {
            gridContentArea.scrollTop = 0;
        }
    }

</script>

@code {
    private bool EnableScrollWorkaround { get; set; } = true;

    private List<Product> GridData { get; set; } = new();

    private int LastId { get; set; }

    private async Task OnGridAdd(GridCommandEventArgs args)
    {
        if (EnableScrollWorkaround)
        {
            await js.InvokeVoidAsync("scrollGridToTop");
        }
    }

    private void OnGridUpdate(GridCommandEventArgs args)
    {
        var updatedItem = (Product)args.Item;
        var originalItemIndex = GridData.FindIndex(i => i.Id == updatedItem.Id);

        if (originalItemIndex != -1)
        {
            GridData[originalItemIndex] = updatedItem;
        }
    }

    private void OnGridCreate(GridCommandEventArgs args)
    {
        var createdItem = (Product)args.Item;

        createdItem.Id = ++LastId;

        GridData.Insert(0, createdItem);
    }

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 30; i++)
        {
            GridData.Add(new Product()
            {
                Id = ++LastId,
                Name = $"Product {LastId}",
                Quantity = (short)Random.Shared.Next(0, 1000),
                StartDate = DateTime.Now.AddDays(-Random.Shared.Next(60, 1000)),
                IsActive = LastId % 4 > 0
            });
        }
    }

    public class Product
    {
        public int Id { get; set; }
        [Required]
        public string Name { get; set; } = string.Empty;
        public decimal Price { get; set; }
        public int Quantity { get; set; }
        public DateTime StartDate { get; set; }
        public bool IsActive { get; set; }
    }
}

Microsoft.JSInterop.JSException: Cannot read properties of null (reading 'addEventListener')
TypeError: Cannot read properties of null (reading 'addEventListener')

<script suppress-error="BL9992">
    window.navigateToHref = (ev) => {
        if (ev.key === "Enter") {
            location.href = ev.target.href
        }
    };
</script>

@* This example shows how to create header and footer for the Drawer and select an item manually. *@
<TelerikDrawer @bind-Expanded="@DrawerExpanded"
               Data="@Data"
               MiniMode="true"
               Mode="@DrawerMode.Push"
               @bind-SelectedItem="@SelectedItem"
               @ref="@DrawerRef">
    <Template>
        @* the header *@
        <div>
            <TelerikButton OnClick="@(() => DrawerRef.ToggleAsync())" Icon="@FontIcon.Menu" />
            @if (DrawerExpanded)
            {
                <div class="text-info" style="border-bottom:solid; font-weight: bold; margin-bottom: 3em; white-space:nowrap">
                    <a href="https://google.com" onkeydown="navigateToHref(event)">
                        My Custom Navigation to Google
                    </a>
                </div>
            }
            else
            {
                <div class="text-info" style="border-bottom:solid; font-weight: bold;">
                    Nav
                </div>
            }
        </div>

        @* custom items rendering and item selection *@

        <div class="k-drawer-items">
            <ul>
                @if (SelectedItem != null && DrawerExpanded)
                {
                    <li class="k-drawer-item" style="white-space:nowrap">
                        <div>
                            <p><strong>@SelectedItem.Text</strong></p>
                            <p>@SelectedItem.Description</p>
                        </div>
                    </li>
                }

                @foreach (var item in Data)
                {
                    @* Use onclick to handle manual item selection *@
                    <li @onclick="@(() => SelectedItem = item)"
                    class="k-drawer-item @GetSelectedItemClass(item)" style="white-space:nowrap">
                        <TelerikFontIcon Icon="@item.Icon"></TelerikFontIcon>
                        @if (DrawerExpanded)
                        {
                            <div>
                                <div>@item.Text</div>
                            </div>
                        }
                    </li>
                }
            </ul>
        </div>

        @* the footer *@
        @if (DrawerExpanded)
        {
            <div style="text-align: center; margin-top: 3em; padding-top: 2em; border-top: 2px solid black; white-space:nowrap">
                <img src="user-avatar.png" alt="my avatar" style="border-radius: 50%; width: 50px; height: 50px;" />
                <br /><br />
                <TelerikButton Icon="@FontIcon.Logout" ThemeColor="primary">Log Out</TelerikButton>
            </div>
        }
    </Template>
    <DrawerContent>
        <div class="m-5">Content for @SelectedItem?.Text - @SelectedItem?.Description</div>
    </DrawerContent>
</TelerikDrawer>


@code {
    public TelerikDrawer<DrawerItem> DrawerRef { get; set; }
    public DrawerItem SelectedItem { get; set; }
    public bool DrawerExpanded { get; set; } = true;
    public IEnumerable<DrawerItem> Data { get; set; } = new List<DrawerItem>
    {
        new DrawerItem {Text = "Shopping Cart", Icon = FontIcon.Cart, Description = "Items in shopping cart"},
        new DrawerItem {Text = "Settings", Icon = FontIcon.Gear, Description = "My profile settings"},
        new DrawerItem {Text = "Notifications", Icon = FontIcon.ExclamationCircle, Description = "My profile notifications"},
        new DrawerItem {Text = "Calendar", Icon = FontIcon.Calendar, Description = "My events"},
    };

    public string GetSelectedItemClass(DrawerItem item)
    {
        if (SelectedItem == null) return string.Empty;
        return SelectedItem.Text.ToLowerInvariant().Equals(item.Text.ToLowerInvariant()) ? "text-info" : "";
    }

    public class DrawerItem
    {
        public string Text { get; set; }
        public FontIcon? Icon { get; set; }
        public string Description { get; set; }
    }
}

@using System.IO

@if (ShouldRenderFileManager)
{
    <TelerikFileManager @ref="@FileManagerRef"
                        Data="@Files"
                        @bind-Path="@DirectoryPath"
                        View="@CurrentView"
                        ViewChanged="@OnViewChanged"
                        Height="400px"
                        OnCreate="@OnCreateHandler"
                        OnUpdate="@OnUpdateHandler"
                        OnDelete="@OnDeleteHandler"
                        OnModelInit="@OnModelInitHandler"
                        OnDownload="@OnDownloadHandler"
                        SelectedItems="@SelectedItems"
                        SelectedItemsChanged="@((IEnumerable<FlatFileEntry> selectedFiles) => OnSelect(selectedFiles))">
    </TelerikFileManager>
}

@foreach (var item in Files)
{
    <div>@item.Name</div>
}

@code {
    private bool ShouldRenderFileManager { get; set; } = true;

    private TelerikFileManager<FlatFileEntry>? FileManagerRef { get; set; }
    private List<FlatFileEntry> Files { get; set; } = new();

    private string DirectoryPath { get; set; } = string.Empty;

    private IEnumerable<FlatFileEntry> SelectedItems { get; set; } = new List<FlatFileEntry>();

    private FileManagerViewType CurrentView { get; set; }

    private void OnViewChanged(FileManagerViewType newView)
    {
        CurrentView = newView;
    }

    private async Task OnCreateHandler(FileManagerCreateEventArgs args)
    {
        var newFolder = args.Item as FlatFileEntry;

        var parent = GetParent(newFolder, DirectoryPath);

        newFolder.Id = "20";
        newFolder.ParentId = parent.Id;
        newFolder.Name = "New folder";
        newFolder.IsDirectory = true;
        newFolder.HasDirectories = false;
        newFolder.DateCreated = DateTime.Now;
        newFolder.DateCreatedUtc = DateTime.Now;
        newFolder.DateModified = DateTime.Now;
        newFolder.DateModifiedUtc = DateTime.Now;
        newFolder.Path = Path.Combine(DirectoryPath, newFolder.Name);
        newFolder.Extension = null;

        var parentDirectory = GetDirectory(DirectoryPath) ?? GetParent(newFolder, DirectoryPath);

        if (parentDirectory != null)
        {
            // Simulate add to the file system.
            newFolder.ParentId = parentDirectory.Id;
            Files.Add(newFolder);
            parentDirectory.HasDirectories = Files.Count(x => x.ParentId == parentDirectory.Id) > 0;
        }
        else
        {
            // Create a folder in the root directory.
            Files.Add(newFolder);
        }

        RefreshData();
    }

    private FlatFileEntry GetDirectory(string path)
    {
        var directory = Files.FirstOrDefault(x => x.IsDirectory && x.Path == path);

        return directory;
    }

    private FlatFileEntry GetParent(FlatFileEntry currItem, string currDirectory)
    {
        var parentItem = Files
            .FirstOrDefault(x => x.IsDirectory && x.Path == currDirectory);

        return parentItem;
    }


    private async Task OnUpdateHandler(FileManagerUpdateEventArgs args)
    {
        var item = args.Item as FlatFileEntry;

        if (item.IsDirectory)
        {
            var name = item.Name ?? string.Empty;

            var updatedItem = Files.FirstOrDefault(x => x.Id == item.Id);
            updatedItem.Name = item.Name;
            updatedItem.Path = Path.Combine(DirectoryPath, name);

            ShouldRenderFileManager = false;
            await Task.Delay(1);
            ShouldRenderFileManager = true;
        }
        else
        {
            // The name property is updated, but also update the path to the file.
            var name = item.Name ?? string.Empty;
            var extension = item.Extension ?? string.Empty;
            var fullName = extension.Length > 0 && name.EndsWith(extension) ?
                name : $"{name}{extension}";

            var updatedItem = Files.FirstOrDefault(x => x.Id == item.Id);

            updatedItem.Name = item.Name;
            updatedItem.Path = Path.Combine(DirectoryPath, fullName);
            Console.WriteLine(updatedItem.Path);
        }
    }

    private async Task OnDownloadHandler(FileManagerDownloadEventArgs args)
    {
        var selectedItem = args.Item as FlatFileEntry;

        // The Filemanager does not have the actual file.
        // Obtain the file contents, based on args.Item, and set the event arguments:

        //args.Stream = the file stream of the actual selected file;
        //args.MimeType = the MIME type of the actual file;
        //args.FileName = the file name that the browser will receive (optional);

        FlatFileEntry actualFile = (FlatFileEntry)args.Item;

        string dummyFileContent = $"This file is a dummy version of {actualFile.Name}. It was downloaded with the Telerik Blazor FileManager.";
        byte[] dummyFileBuffer = System.Text.Encoding.UTF8.GetBytes(dummyFileContent);

        args.Stream = new MemoryStream(dummyFileBuffer);
        args.MimeType = "text/plain";
        args.FileName = $"filemanager-{actualFile.Name}-{DateTime.Now.ToString("yyyy-MM-dd-HH-mm-ss")}.txt";
    }

    private async Task OnDeleteHandler(FileManagerDeleteEventArgs args)
    {
        var currItem = args.Item as FlatFileEntry;

        var itemToDelete = Files.FirstOrDefault(x => x.Id == currItem.Id);

        Files.Remove(itemToDelete);

        RefreshData();
    }

    private FlatFileEntry OnModelInitHandler()
    {
        var item = new FlatFileEntry();
        item.Name = $"New folder";
        item.Size = 0;
        item.Path = Path.Combine(DirectoryPath, item.Name);
        item.IsDirectory = true;
        item.HasDirectories = false;
        item.DateCreated = DateTime.Now;
        item.DateCreatedUtc = DateTime.Now;
        item.DateModified = DateTime.Now;
        item.DateModifiedUtc = DateTime.Now;

        return item;
    }

    private void OnSelect(IEnumerable<FlatFileEntry> selectedFiles)
    {
        // Update the view model.
        SelectedItems = selectedFiles;
    }

    private void RefreshData()
    {
        Files = new List<FlatFileEntry>(Files);
    }

    protected override async Task OnInitializedAsync()
    {
        Files = await GetFlatFileEntries();
    }

    public class FlatFileEntry
    {
        public string Id { get; set; }
        public string ParentId { get; set; }
        public string Name { get; set; }
        public long Size { get; set; }
        public string Path { get; set; }
        public string Extension { get; set; }
        public bool IsDirectory { get; set; }
        public bool HasDirectories { get; set; }
        public DateTime DateCreated { get; set; }
        public DateTime DateCreatedUtc { get; set; }
        public DateTime DateModified { get; set; }
        public DateTime DateModifiedUtc { get; set; }
    }

    // the next lines are hardcoded data generation so you can explore the FileManager freely

    private async Task<List<FlatFileEntry>> GetFlatFileEntries()
    {
        var workFiles = new FlatFileEntry()
        {
            Id = "1",
            ParentId = null,
            Name = "Work Files",
            IsDirectory = true,
            HasDirectories = true,
            DateCreated = new DateTime(2022, 1, 2),
            DateCreatedUtc = new DateTime(2022, 1, 2),
            DateModified = new DateTime(2022, 2, 3),
            DateModifiedUtc = new DateTime(2022, 2, 3),
            Path = Path.Combine("files"),
            Size = 3 * 1024 * 1024
        };

        var Documents = new FlatFileEntry()
        {
            Id = "2",
            ParentId = workFiles.Id,
            Name = "Documents",
            IsDirectory = true,
            HasDirectories = false,
            DateCreated = new DateTime(2022, 1, 2),
            DateCreatedUtc = new DateTime(2022, 1, 2),
            DateModified = new DateTime(2022, 2, 3),
            DateModifiedUtc = new DateTime(2022, 2, 3),
            Path = Path.Combine(workFiles.Path, "documents"),
            Size = 1024 * 1024
        };

        var Images = new FlatFileEntry()
        {
            Id = "3",
            ParentId = workFiles.Id,
            Name = "Images",
            IsDirectory = true,
            HasDirectories = false,
            DateCreated = new DateTime(2022, 1, 2),
            DateCreatedUtc = new DateTime(2022, 1, 2),
            DateModified = new DateTime(2022, 2, 3),
            DateModifiedUtc = new DateTime(2022, 2, 3),
            Path = Path.Combine(workFiles.Path, "images"),
            Size = 2 * 1024 * 1024
        };

        var files = new List<FlatFileEntry>()
{
            workFiles,

            Documents,

            Images
        };

        return files;
    }
}

Microsoft.JSInterop.JSException: Cannot read properties of null (reading 'addEventListener')
TypeError: Cannot read properties of null (reading 'addEventListener')

System.OverflowException: Value was either too large or too small for a Decimal.