[英]Blazor Pass EventCallback as Class Property To Component
我正在嘗試在 Blazor 中開發一個組件,我希望它從 C# 類中獲取其所有功能(文本、EventCallbacks 等)。 像這樣的東西:
Blazor 組件(代碼隱藏):
public partial class Card : ComponentBase
{
[Parameter] public CardData CardData { get; set; }
protected async Task OnActionFiredEvent(EventCallback<object> eventCallback, object itemId)
{
if (eventCallback.HasDelegate)
await CardData.CardTitleOnClickAction.InvokeAsync(itemId);
}
}
Blazor 組件(剃刀):
<!-- Card image -->
<div class="view view-cascade overlay">
<a>
<div class="mask rgba-white-slight waves-effect waves-light"></div>
</a>
</div>
<!-- Card content -->
<div class="card-body card-body-cascade text-center">
<!-- Title -->
<h4 class="card-title">
<a class="waves-effect waves-light" @onclick="@(() => OnActionFiredEvent(CardData.CardTitleOnClickAction, CardData.CardItemId))">
<strong>@CardData.CardTitle</strong>
</a>
</h4>
<!-- Subtitle -->
@if (!string.IsNullOrEmpty(CardData.CardSubTitle))
{
<h6 class="font-weight-bold indigo-text py-2">@CardData.CardSubTitle</h6>
}
<!-- Text -->
@if (!string.IsNullOrEmpty(CardData.CardText))
{
<p class="card-text">
@CardData.CardText
</p>
}
</div>
<!-- Card footer -->
<div class="card-footer text-muted text-center">
@CardData.CardFooter
</div>
CarData 類:
public class CardData
{
public object CardItemId { get; set; }
public string CardTitle { get; set; }
public string CardSubTitle { get; set; }
public string CardText { get; set; }
public string CardFooter { get; set; }
public EventCallback<object> CardTitleOnClickAction { get; set; }
}
用:
<Card CardData="@(new CardData() {
CardTitle = "TextTitle",
CardTitleOnClickAction = EventCallBackMethod,
CardSubTitle = "TextSubTitle",
CardText = "Text"})" />
問題是我在將 EventCallBack 作為類屬性傳遞時收到以下錯誤:無法將方法組“EventCallBackMethod”轉換為非委托類型“EventCallback”。 您是否打算調用該方法?
失敗的方法本身是這樣的:
protected async Task EventCallBackMethod()
{
await DoSomething();
}
知道如何解決這個問題嗎?
正如布賴恩·帕克 (Brian Parker) 所提到的,您的回調中需要有一個類型。 例如,如果您不想傳遞值,則可以傳遞null
;
MyComponent.razor
<button @onclick="OnButtonClicked">Click me</button>
@code{
[Parameter]
public EventCallback ButtonClicked{ get; set; }
protected async Task OnButtonClicked()
{
await ButtonClicked.InvokeAsync(null);
}
}
例如作為剃刀組件,按鈕點擊觸發OnButtonClicked
,然后調用ButtonClicked
參數,該參數可以在父頁面中引用。
Page.razor
@page "/pagename"
<MyComponent ButtonClicked="@ButtonClickedHandler" />
@code{
protected void ButtonClickedHandler()
{
Logger.LogInfo("Button click was handled on the page");
}
}
如果你想傳遞參數,你可以這樣做:
MyNextComponent.razor
<button @onclick="OnButtonClicked">Click me</button>
@code{
[Parameter]
public EventCallback<bool> ButtonClicked{ get; set; }
protected async Task OnButtonClicked(bool value)
{
await ButtonClicked.InvokeAsync(true);
}
}
Page.razor @page "/pagename"
<MyNextComponent ButtonClicked="@ButtonClickedHandler" />
@code{
protected void ButtonClickedHandler(bool value)
{
Logger.LogInfo($"Button click was handled on the page: {value}");
}
}
像這樣創建您的 EventCallback
private async Task Press1()
{
this.message = "F1";
}
EventCallback evt1 = EventCallback.Factory.Create(this, Press1);
財產
public class CardData
{
public EventCallback<object> CardTitleOnClickAction { get; set; }
public static EventCallback GetEvent(CardData data)
{
return data.CardTitleOnClickAction;
}
}
成分
@onclick="() =>Modal.CardData.GetEvent(data).InvokeAsync()"
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