Blazor入门-调用js+例子

参考：
Blazor入门笔记（3）-C#与JS交互 - 半野 - 博客园
https://www.cnblogs.com/zxyao/p/12638233.html

本地环境：win10, visual studio 2022 community

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其他例子写了再更新！

调用js函数并传递参数

首先要加上@inject IJSRuntime JsRuntime，在需要调用的地方写：

var name = "world";
var a = 11;
var b = 22;
var element = await JsRuntime.InvokeAsync<string>("interop.runJs", name, a, b);

其中runJs是函数的名称，后面是参数列表。element将得到返回值。再看runJs：

<script>window.interop = {runJs: (name, a, b) => {console.warn("runJs is executing");console.warn("hello " + name);return "OK " + (a + b);}}
</script>

绘制一个半径可随窗口大小变化的圆形

@page "/"@inject IJSRuntime JsRuntime<PageTitle>Index</PageTitle><svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg"><circle id="circle" cx="50" cy="50" r="@radius" fill="blue" />
</svg>@code {private double radius = 20;protected override async Task OnAfterRenderAsync(bool firstRender){if (firstRender){await UpdateCircleRadius();}}async Task UpdateCircleRadius(){var element = await JsRuntime.InvokeAsync<IJSObjectReference>("document.getElementById", "circle");var width = await element.InvokeAsync<int>("getBoundingClientRect").ConfigureAwait(false);radius = width / 10;}
}