@result

<TelerikButton OnClick="@ToggleWindow">Toggle the Window</TelerikButton>

<TelerikWindow Visible="@isVisible" VisibleChanged="@VisibleChangedHandler">
    <WindowTitle>
        <strong>The Title</strong>
    </WindowTitle>
    <WindowContent>
        This is my window <strong>popup</strong> content.
    </WindowContent>
    <WindowActions>
        <WindowAction Name="MyCustomClose" Icon="@IconName.Close" OnClick="@MyCustomCloseHandler" />
    </WindowActions>
</TelerikWindow>

@code {
    bool isVisible { get; set; }
    string result { get; set; }

    void VisibleChangedHandler(bool currVisible)
    {
        // if you don't do this, the window won't close because of the user action
        // so if you don't update the view-model here, the window will not close when Esc is pressed

        //isVisible = currVisible;

        result = $"the window is now visible: {isVisible}";

        Console.WriteLine($"Closing because of Esc key");
    }

    void MyCustomCloseHandler()
    {
        //will fire on click only
        isVisible = false;
        //since the built-in window UI didn't invoke this change, the event will not fire
    }

    public void ToggleWindow()
    {
        isVisible = !isVisible;

        result = $"the window is now visible: {isVisible}";
    }
}