@inject IJSRuntime js

<TelerikEditor @bind-Value="@EditorValue" />

@* Move scripts to separate js files in production. *@
<script suppress-error="BL9992">
    function injectEditorStyleTag() {
        var doc = document.querySelector("iframe").contentWindow.document;
        var head = doc.querySelector("head");
        
        var style = doc.createElement("style");
        style.type = "text/css";
        
        var css = "body { background: #fed; font-size: 24px; }";
        
        style.appendChild(doc.createTextNode(css));
        head.appendChild(style);
    }
</script>

@code {
    private string EditorValue { get; set; } = "<p>The default font-size is 24px.</p>";

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            await js.InvokeVoidAsync("injectEditorStyleTag");
        }
    }
}

@using Telerik.Blazor.Components.Editor

<TelerikButton OnClick="@InsertTable">Insert Table</TelerikButton>

<TelerikEditor @ref="@TheEditor" Value="@TheContent" ValueChanged="@ValueChangedHandler"></TelerikEditor>

@code {
    TelerikEditor TheEditor { get; set; }

    string TheContent { get; set; } = "<p>Lorem ipsum.</p><p>Dolor sit amet.</p>";

    void ValueChangedHandler(string value)
    {
        var checkEnd = value.EndsWith("</table>");

        TheContent = checkEnd == true ? value + "<p></p>" : value;
    }

    async Task InsertTable()
    {
        await TheEditor.ExecuteAsync(new TableCommandArgs(4, 4));
    }
}

@using Telerik.Blazor.Components.Editor

<TelerikButton OnClick="@( () => WindowIsVisible = !WindowIsVisible )">Insert Html</TelerikButton>

<TelerikEditor @ref="@TheEditor" @bind-Value="@TheContent"></TelerikEditor>

<TelerikWindow @bind-Visible="@WindowIsVisible">
    <WindowTitle>
        <strong>Insert Html</strong>
    </WindowTitle>
    <WindowContent>
        <TelerikTextArea @bind-Value="@HtmlToInsert"></TelerikTextArea>
        <TelerikButton OnClick="@InsertHtml">Insert</TelerikButton>
    </WindowContent>
</TelerikWindow>

@code{

    public string HtmlToInsert { get; set; }

    bool WindowIsVisible { get; set; }

    TelerikEditor TheEditor { get; set; }

    string TheContent { get; set; } = "<p>Lorem ipsum.</p><p>Dolor sit amet.</p>";

    async Task InsertHtml()
    {
        await TheEditor.ExecuteAsync(new HtmlCommandArgs("insertHtml", $"<div>{HtmlToInsert}</div>"));

        WindowIsVisible = !WindowIsVisible;

        HtmlToInsert = "";
    }
}

<TelerikEditor @bind-Value="@EditorContent">
    <EditorSettings>
        <EditorPasteSettings 
                             RemoveAttributes="@( new List<string>() )"
                            >
        </EditorPasteSettings>
    </EditorSettings>
</TelerikEditor>

@EditorContent

@code{
    string EditorContent { get; set; }
}

@using System.ComponentModel.DataAnnotations;
@using Telerik.Blazor.Components.Editor

<TelerikForm Model="@Model" OnSubmit="@OnSubmitHandler">
    <FormValidation>
        <DataAnnotationsValidator />
        <ValidationSummary />
    </FormValidation>
    <FormItems>
        <FormItem>
            <Template>
                <TelerikEditor @bind-Value="@Model.Name" @ref="@EditorRef" />
            </Template>
        </FormItem>
    </FormItems>
</TelerikForm>

@code {
    public SampleData Model { get; set; } = new SampleData();
    public TelerikEditor EditorRef { get; set; }

    private async Task OnSubmitHandler(EditContext editContext)
    {
        bool isFormValid = editContext.Validate();

        if (isFormValid)
        {
            //some logic here
        }
        else
        {
            await EditorRef.ExecuteAsync(new HtmlCommandArgs("setHtml", "")); //workaround

            //clear the content of the editor to let the user type anew
            Model.Name = String.Empty;
        }
    }

    public class SampleData
    {
        [Required]
        [MinLength(30, ErrorMessage = "The content should be minimum 30 characters long.")]
        public string Name { get; set; }
    }
}