Blazor:单击按钮时调用服务器方法吗? [英] Blazor: Call a server method when a button is clicked?

问题描述

我创建了一个示例Blazor项目.脚手架有两个示例，(1)调用网页中存在的C#方法=计数器，(2)在网页初始化=天气表的开始处调用服务器方法.但是，没有任何单击按钮时调用服务器方法并获得结果的示例.有可能吗?

I created a sample Blazor project. The scaffolding has two examples, (1)calling a C# method that exists IN the web page = counter, (2)calling a server method at the BEGINNING of the web page initialisation = weather table. But not any example for calling a server method and get result when a button is clicked. Is that possible?

例如，我可以在"WeathrForecastService.cs"中添加这样的方法吗?

For example, can I add a method like this to the "WeathrForecastService.cs":

    public int Add(int a, int b)
    {
        return a + b;
    }

并像计数器"示例一样，在页面上添加一个按钮，然后单击该按钮，显示其结果:

and like the "counter" example, add a button on the page, and when the button is clicked, display the result of it:

@page "/fetchdata"

@using BlazorApp1.Data
@inject WeatherForecastService ForecastService

<h1>Weather forecast</h1>

<p>This component demonstrates fetching data from a service.</p>

@if (forecasts == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <p>Current count: @[display the result of ForecastService.Add(1,2)]</p>
    <button class="btn btn-primary" @onclick="[call ForecastService.Add(1,2)]">Click me</button>
}

@code {
    WeatherForecast[] forecasts;

    protected override async Task OnInitializedAsync()
    {
        forecasts = await ForecastService.GetForecastAsync(DateTime.Now);
    }
}

推荐答案

调用服务器方法并在单击按钮时获取结果.有可能吗?

calling a server method and get result when a button is clicked. Is that possible?

是的.如果您使用的是Blazor服务器端，则将通过内部的SignalR调用服务器端方法.

Yes. If you're using Blazor Server Side, the server side method will be invoked via SignalR under the hood.

类似于我们在Angular/React中所做的那样，为了显示结果，我们需要创建一个_sum字段来缓存结果，以便以后可以显示/更改它:

Similar to the way we do in Angular/React, in order to display the result, we need create a _sum field to cache the result so that we can display/change it later:

@code {
    private int _sum;
}

并如下更改您的onclick:

<p>Current count: @this._sum</p>
<button class="btn btn-primary" @onclick="()=>this._sum= ForecastService.Add(1, 2)" >Click me</button>

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