5
我在窗體的構造，在InitializeComponent後，下面的代碼：WebClient.DownloadDataAsync被凍結我的UI
using (WebClient client = new WebClient())
{
client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);
client.DownloadDataAsync("http://example.com/version.txt");
}
當我開始我的形式，直到client_DownloadDataCompleted提高用戶界面不會出現。 client_DownloadDataCompleted方法爲空，所以這裏沒有問題。
我在做什麼錯了？ 如何在不凍結UI的情況下做到這一點？
謝謝你的時間。
此致敬禮。
全碼：
Program.cs的
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());
}
}
}
Form1.cs的
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;
}
}
你的意思是DownloadData或DownloadString？ – chakrit 2008-11-07 11:41:49
你是否設法解決這個問題？ – 2008-11-12 23:16:23
分辨率爲`client.Proxy = null;`。看到這個答案類似的問題：http://stackoverflow.com/questions/4415443/system-net-webclient-unreasonably-slow/4420429#4420429 – 2011-05-28 00:03:42