ConfigureAwait.aspx
<%@ Page Language="C#" AutoEventWireup="true" Async="true" CodeBehind="ConfigureAwait.aspx.cs" Inherits="ConcurrencyWebForm.ConfigureAwait" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="btnSyncWithoutConfigureAwait" runat="server" Text="SyncWithoutConfigureAwait" OnClick="btnSyncWithoutConfigureAwait_Click" />
<br />
<asp:Button ID="btnSyncWithConfigureAwait" runat="server" Text="SyncWithConfigureAwait" OnClick="btnSyncWithConfigureAwait_Click" />
<br />
<asp:Button ID="btnAsyncWithConfigureAwait" runat="server" Text="AsyncWithConfigureAwait" OnClick="btnAsyncWithConfigureAwait_Click" />
</div>
</form>
</body>
</html>
ConfigureAwait.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace ConcurrencyWebForm
{
public partial class ConfigureAwait : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
//此例會造成Deadlock
//ps.以同步的方式執行非同步的function是非常不建議的
protected void btnSyncWithoutConfigureAwait_Click(object sender, EventArgs e)
{
Task tVal = DoSomethingAsync();
string abc = "";
string cde = "";
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('" + tVal.Result.ToString() + "');", true);
}
private async Task DoSomethingAsync()
{
int val = 13;
// Asynchronously wait 3 second.
//只是為了讓此library function為非同步執行才用Task.Delay，實際尚無特別意義
await Task.Delay(TimeSpan.FromSeconds(3));
val *= 2;
// Asynchronously wait 3 second.
await Task.Delay(TimeSpan.FromSeconds(3));
return val;
}
protected void btnSyncWithConfigureAwait_Click(object sender, EventArgs e)
{
Task tVal = DoSomethingAsyncWithConfigureAwait();
string abc = "";
string cde = "";
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('" + tVal.Result.ToString() + "');", true);
}
//.ConfigureAwait(false)另開了context以儲存library function的執行狀態
private async Task DoSomethingAsyncWithConfigureAwait()
{
int val = 13;
// Asynchronously wait 3 second.
//增加了.ConfigureAwait(false)另開了context
await Task.Delay(TimeSpan.FromSeconds(3)).ConfigureAwait(false);
val *= 2;
// Asynchronously wait 3 second.
//增加了.ConfigureAwait(false)另開了context
await Task.Delay(TimeSpan.FromSeconds(3)).ConfigureAwait(false);
return val;
}
protected async void btnAsyncWithConfigureAwait_Click(object sender, EventArgs e)
{
int intVal = await DoSomethingAsyncWithConfigureAwait();
string abc = "";
string cde = "";
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('" + intVal.ToString() + "');", true);
}
}
}
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