如何在 blazor 服务器端渲染页面时停止 IDisposable 调用? [英] How can I stop IDisposable invokes while render the page in blazor server-side?
问题描述
这是我的代码:
@page "/"
@using Microsoft.AspNetCore.Components.Server.Circuits
@inject CircuitHandler circuitHandler
@implements IDisposable
<h1>Hello, world!</h1>
Welcome to your new app.
@code{
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (firstRender)
{
Console.WriteLine("123");//do something
}
}
#region//circuitHandler
protected override void OnInitialized()
{
// Subscribe to the event handler
(circuitHandler as CircuitHandlerService).CircuitsChanged +=
HandleCircuitsChanged;
}
public void HandleCircuitsChanged(object sender, EventArgs args)
{
Console.WriteLine("123");//do something
}
public void Dispose()
{
(circuitHandler as CircuitHandlerService).CircuitsChanged -=
HandleCircuitsChanged;
}
#endregion
}
using Microsoft.AspNetCore.Components.Server.Circuits;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace BlazorApp2
{
public class CircuitHandlerService : CircuitHandler
{
public ConcurrentDictionary<string, Circuit> Circuits
{
get;
set;
}
public event EventHandler CircuitsChanged;
protected virtual void OnCircuitsChanged()
=> CircuitsChanged?.Invoke(this, EventArgs.Empty);
public CircuitHandlerService()
{
Circuits = new ConcurrentDictionary<string, Circuit>();
}
public override Task OnCircuitOpenedAsync(Circuit circuit,
CancellationToken cancellationToken)
{
Circuits[circuit.Id] = circuit;
//OnCircuitsChanged();
return base.OnCircuitOpenedAsync(circuit,
cancellationToken);
}
public override Task OnCircuitClosedAsync(Circuit circuit,
CancellationToken cancellationToken)
{
Circuit circuitRemoved;
Circuits.TryRemove(circuit.Id, out circuitRemoved);
OnCircuitsChanged();
return base.OnCircuitClosedAsync(circuit,
cancellationToken);
}
public override Task OnConnectionDownAsync(Circuit circuit,
CancellationToken cancellationToken)
{
return base.OnConnectionDownAsync(circuit,
cancellationToken);
}
public override Task OnConnectionUpAsync(Circuit circuit,
CancellationToken cancellationToken)
{
return base.OnConnectionUpAsync(circuit, cancellationToken);
}
}
}
我需要 CircuitHandler
来了解页面是否关闭.
现在我遇到了一个奇怪的问题.当页面被加载时,即使页面没有关闭,IDisposable
总是会被调用.
更重要的是,OnAfterRenderAsync
中有几个代码.当IDisposable
调用时,OnAfterRenderAsync
中没有运行完的代码会突然断掉,没有任何错误.
有人告诉我设置
I need the CircuitHandler
to get to know whether the page is closed.
Now I met a strange problem. When the page is loaded, the IDisposable
always invoke even the page is not closed.
What's more, there are several codes in OnAfterRenderAsync
. When the IDisposable
invokes, the codes in OnAfterRenderAsync
which not runs finished will suddenly break without any error.
Someone told me to set the
@(await Html.RenderComponentAsync<App>(RenderMode.ServerPrerendered))
在_Host.cshtml
到
@(await Html.RenderComponentAsync<App>(RenderMode.Server))
可以解决这个问题.
我试过了,问题依旧.
我该如何解决这个问题?谢谢.
can solve this.
I tried, but the problem still here.
How can I solve this? Thank you.
推荐答案
下面的代码片段与您的完全一样,对我来说非常好.Dispose 方法仅在电路关闭时调用.我会在下面发布我使用的完整代码,复制并运行它,然后我会尝试帮助您解决其他问题.
the code snippet below is exactly like yours, and it works for me perfectly fine. The Dispose method is called only when a Circuit is closed. I'll post below the entire code I use, copy and run it, then I'll try to help with other issues you have.
<app>
@(await Html.RenderComponentAsync<App>(RenderMode.Server))
</app>
注意:我在这里发布整个文件的内容.你必须用你的命名空间来调整我的应用程序的命名空间.
Note: I'm posting here entire files' content. You'll have to adjust the namespaces of my app with yours.
using Microsoft.AspNetCore.Components.Server.Circuits;
using System;
using System.Collections.Concurrent;
using System.Threading;
using System.Threading.Tasks;
namespace BlazorCircuitHandler.Services
{
public class CircuitHandlerService : CircuitHandler
{
public ConcurrentDictionary<string, Circuit> Circuits { get; set; }
public event EventHandler CircuitsChanged;
protected virtual void OnCircuitsChanged()
=> CircuitsChanged?.Invoke(this, EventArgs.Empty);
public CircuitHandlerService()
{
Circuits = new ConcurrentDictionary<string, Circuit>();
}
public override Task OnCircuitOpenedAsync(Circuit circuit, CancellationToken cancellationToken)
{
Circuits[circuit.Id] = circuit;
OnCircuitsChanged();
return base.OnCircuitOpenedAsync(circuit, cancellationToken);
}
public override Task OnCircuitClosedAsync(Circuit circuit, CancellationToken cancellationToken)
{
Circuit circuitRemoved;
Circuits.TryRemove(circuit.Id, out circuitRemoved);
OnCircuitsChanged();
return base.OnCircuitClosedAsync(circuit, cancellationToken);
}
public override Task OnConnectionDownAsync(Circuit circuit, CancellationToken cancellationToken)
{
return base.OnConnectionDownAsync(circuit, cancellationToken);
}
public override Task OnConnectionUpAsync(Circuit circuit, CancellationToken cancellationToken)
{
return base.OnConnectionUpAsync(circuit, cancellationToken);
}
}
}
Index.razor 的代码
@page "/"
@using Microsoft.AspNetCore.Components.Server.Circuits
@using BlazorCircuitHandler.Services
@inject CircuitHandler circuitHandler
@implements IDisposable
<p>
Number of Circuits: @((circuitHandler as
BlazorCircuitHandler.Services.CircuitHandlerService).Circuits.Count)
<ul>
@foreach (var circuit in (circuitHandler as
BlazorCircuitHandler.Services.CircuitHandlerService).Circuits)
{
<li>@circuit.Key</li>
}
</ul>
</p>
@code {
protected override void OnInitialized()
{
(circuitHandler as CircuitHandlerService).CircuitsChanged +=
HandleCircuitsChanged;
}
public void Dispose()
{
(circuitHandler as CircuitHandlerService).CircuitsChanged -=
HandleCircuitsChanged;
}
public void HandleCircuitsChanged(object sender, EventArgs args)
{
InvokeAsync(() => StateHasChanged());
}
}
还有创业班
public void ConfigureServices(IServiceCollection services)
{
// Removed for brevity....
services.AddSingleton<CircuitHandler>(new CircuitHandlerService());
}
当然还有_Host.cshtml
<app>
@(await Html.RenderComponentAsync<App>(RenderMode.Server))
</app>
请不要漏报...
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