How set Eventcallback<> by Code

Question

User62590854 posted

Hello,

I apologize for my ignorance but I need helt to some base of C#

I made a blazor component:

        <FidaBlazorUI.FlexContainer FlexBehaviour="FlexBehaviour.d_flex" @attributes="@Attributes">
            <FlexContainer Style="margin-right:0.31em">
                <span>@Nome</span>
            </FlexContainer>
            <FlexContainer Style="margin-right:0.31em">
                <span>@Start - @End</span>
            </FlexContainer>
            <FlexContainer>
                <span>@Place</span>
            </FlexContainer>
            <FlexContainer Style="font-size:0.9em">
                <Button Text="@ButtonText"
                        Type="BtnType.button"
                        ButtonStyle="BtnStyle.primary"
                        ButtonClick="@(() => { ButtonClick.InvokeAsync(WorkSheet); })" />
            </FlexContainer>
        </FidaBlazorUI.FlexContainer>
@code {
    [CascadingParameter]
    public CalendarTemplate TemplateType { get; set; }
    [Parameter]
    public object WorkSheet { get; set; }
    [Parameter]
    public CalendarTaskType CalendarTaskType { get; set; }
    [Parameter]
    public bool Confirmed { get; set; }
    [Parameter]
    public string Nome { get; set; }
    [Parameter]
    public string Start { get; set; }
    [Parameter]
    public string End { get; set; }
    [Parameter]
    public string Place { get; set; }
    [Parameter]
    public EventCallback<object> ButtonClick { get; set; }
    private string style;
    [Parameter]
    public string Style
    {
        get => style;
        set
        {
            style = value;
            Attributes.SetStyleKey(value);
        }
    }
    [Parameter]
    public string ButtonText { get; set; }
    public CalendarTask()
    {
    }
    public CalendarTask(object workSheet, string nome, string start, string end, string place, string buttonText, EventCallback<object> buttonClick)
    {
        this.WorkSheet = workSheet;
        this.Nome = nome;
        this.Start = start;
        this.End = end;
        this.Place = place;
        this.ButtonText = buttonText;
        this.ButtonClick = buttonClick;
    }
    private Dictionary<string, object> Attributes = new();
}

Where there is a button that invoke an EventCallback that return an object (Worksheet in my case).

With a normal implementation the use of new Component and related Eventcallback would be:

    <FidaBlazorUI.FastCalendar.CalendarTask ButtonClick="@(val => { OnButtonClick(val); })" />

But I need to instantiate a new CalendarTask by code like it:

row.Child = new FidaBlazorUI.FastCalendar.CalendarTask(ws,
                            GetName(ws, "myName"),
                            row.Start.GetFormattedTime(TimeSpanFormat.HourMinutes),
                            row.End.GetFormattedTime(TimeSpanFormat.HourMinutes),
                            GetPlace(ws),
                            txt.Translate("Open Task"), ????);

The problem is that I dont know how pass the EventCallBack parameter  "ButtonClick"

the equivalent in code of this lambda expression: ButtonClick="@(val => { OnButtonClick(val); })"

Thankyou for help

Answer 1

User-2054057000 posted

EventCallback are helpful in creating 2 way binding between parent and child components. This is also known as chain binding. 

Recommend you to refer - Custom Binding between Parent & Child components – “chained bind”