C# WebClient.DownloadDataAsync正在冻结我的UI_C#_.net_Webclient

C# WebClient.DownloadDataAsync正在冻结我的UI

c# .net

C# WebClient.DownloadDataAsync正在冻结我的UI,c#,.net,webclient,C#,.net,Webclient,在我的表单构造函数中，InitializeComponent之后有以下代码： using (WebClient client = new WebClient()) { client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); client.DownloadDataAsync("http://example.com/version.txt"

在我的表单构造函数中，InitializeComponent之后有以下代码：

using (WebClient client = new WebClient())
{
    client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);
    client.DownloadDataAsync("http://example.com/version.txt");
}

当我启动表单时，用户界面直到客户端下载数据完成后才会出现。 client_DownloadDataCompleted方法为空，因此没有问题

我做错了什么？如何在不冻结UI的情况下执行此操作

谢谢您抽出时间。
致以最良好的祝愿

完整代码：

Program.cs

using System;
using System.Windows.Forms;

namespace Lala
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

using System;
using System.Net;
using System.Windows.Forms;

namespace Lala
{
    public partial class Form1 : Form
    {
        WebClient client = new WebClient();

        public Form1()
        {
            client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);
            client.DownloadDataAsync(new Uri("http://www.google.com"));
            InitializeComponent();
        }

        void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
        {
            textBox1.Text += "A";
        }
    }

    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 12);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(12, 41);
            this.textBox1.Multiline = true;
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(468, 213);
            this.textBox1.TabIndex = 1;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(492, 266);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.TextBox textBox1;
    }
}

使用系统；
使用System.Windows.Forms；
名称空间拉拉
{
静态类程序
{
/// 
///应用程序的主要入口点。
/// 
[状态线程]
静态void Main（）
{
Application.EnableVisualStyles（）；
Application.SetCompatibleTextRenderingDefault（false）；
Application.Run（新Form1（））；
}
}
}

Form1.cs

using System;
using System.Windows.Forms;

namespace Lala
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

using System;
using System.Net;
using System.Windows.Forms;

namespace Lala
{
    public partial class Form1 : Form
    {
        WebClient client = new WebClient();

        public Form1()
        {
            client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);
            client.DownloadDataAsync(new Uri("http://www.google.com"));
            InitializeComponent();
        }

        void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
        {
            textBox1.Text += "A";
        }
    }

    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 12);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(12, 41);
            this.textBox1.Multiline = true;
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(468, 213);
            this.textBox1.TabIndex = 1;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(492, 266);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.TextBox textBox1;
    }
}

使用系统；
Net系统；
使用System.Windows.Forms；
名称空间拉拉
{
公共部分类Form1:Form
{
WebClient客户端=新的WebClient（）；
公共表格1（）
{
client.DownloadDataCompleted+=新的DownloadDataCompletedEventHandler（client\u DownloadDataCompleted）；
client.DownloadDataAsync（新Uri（“http://www.google.com"));
初始化组件（）；
}
无效客户端\u DownloadDataCompleted（对象发送方，DownloadDataCompletedEventArgs e）
{
textBox1.Text+=“A”；
}
}
部分类Form1
{
/// 
///必需的设计器变量。
/// 
private System.ComponentModel.IContainer components=null；
/// 
///清理所有正在使用的资源。
/// 
///如果应释放托管资源，则为true；否则为false。
受保护的覆盖无效处置（布尔处置）
{
if（处理和（组件！=null））
{
组件。Dispose（）；
}
基地。处置（处置）；
}
#区域Windows窗体设计器生成的代码
/// 
///设计器支持所需的方法-不修改
///此方法的内容与代码编辑器一起使用。
/// 
私有void InitializeComponent（）
{
this.button1=new System.Windows.Forms.Button（）；
this.textBox1=new System.Windows.Forms.TextBox（）；
这个.SuspendLayout（）；
// 
//按钮1
// 
this.button1.Location=新系统图纸点（12,12）；
this.button1.Name=“button1”；
this.button1.Size=新系统图纸尺寸（75,23）；
this.button1.TabIndex=0；
this.button1.Text=“button1”；
this.button1.UseVisualStyleBackColor=true；
// 
//文本框1
// 
this.textBox1.Location=新系统.图纸.点（12,41）；
this.textBox1.Multiline=true；
this.textBox1.Name=“textBox1”；
this.textBox1.Size=新系统.Drawing.Size（468213）；
this.textBox1.TabIndex=1；
// 
//表格1
// 
此.AutoScaleDimensions=新系统.Drawing.SizeF（6F，13F）；
this.AutoScaleMode=System.Windows.Forms.AutoScaleMode.Font；
this.ClientSize=新系统.Drawing.Size（492266）；
this.Controls.Add（this.textBox1）；
this.Controls.Add（this.button1）；
this.Name=“Form1”；
this.Text=“Form1”；
此选项为.resume布局（false）；
这个。执行布局（）；
}
#端区
private System.Windows.Forms.Button按钮1；
private System.Windows.Forms.TextBox textBox1；
}
}

如果要在不同的线程中运行下载，请参阅作为起点。

我已经尝试了您的代码，效果很好

运行此操作时，能否发布Main（Args[]）方法以及a和b的值：

    int a, b;
    ThreadPool.GetMaxThreads(out a, out b);

我在.NET3.5和VS2008中试用过。我有点不知所措，但我确信这与您机器上的设置有关。不是代码。检查以下内容：

检查线程池（上图）。我得到a=250，b=1000
禁用所有第三方插件
加载VS“清洁”（是否重新启动）
关闭尽可能多的程序/服务
检查你的IE配置。我认为该类使用IE代码/设置
防火墙？杀毒软件
在另一台电脑上试试

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