C# WinForm窗体如何在窗体加载时显示进度条???

nlqtonglin2006 2009-06-29 10:33:57

在打开子窗体时访问不不访问数据库窗体打开都很慢，如何在打开时显示正在加载不让用户感到死机

...全文

4346 19 打赏收藏转发到动态举报

写回复

用AI写文章

19 条回复

切换为时间正序

请发表友善的回复…

发表回复

yiqinqian 2010-10-12

打赏
举报

急需，代码提供·····

lenovore 2010-09-09

打赏
举报

关注！！！

qqiuzaihui 2009-06-29

打赏
举报

使用线程，给你一个例子，你研究一下。把它的计算数列过程改成加载数据就行了。

//例：计算Fibonacci数列，并实时滚动进度条
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.ComponentModel;

class FibonacciNumber : Form
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new FibonacciNumber());
}

private StatusStrip progressStatusStrip;
private ToolStripProgressBar toolStripProgressBar;
private NumericUpDown requestedCountControl;
private Button goButton;
private TextBox outputTextBox;
private BackgroundWorker backgroundWorker;
private ToolStripStatusLabel toolStripStatusLabel;
private int requestedCount;

public FibonacciNumber()
{
Text = "Fibonacci";

// Prepare the StatusStrip.
progressStatusStrip = new StatusStrip();
toolStripProgressBar = new ToolStripProgressBar();
toolStripProgressBar.Enabled = false;
toolStripStatusLabel = new ToolStripStatusLabel();
progressStatusStrip.Items.Add(toolStripProgressBar);
progressStatusStrip.Items.Add(toolStripStatusLabel);

FlowLayoutPanel flp = new FlowLayoutPanel();
flp.Dock = DockStyle.Top;

Label beforeLabel = new Label();
beforeLabel.Text = "Calculate the first ";
beforeLabel.AutoSize = true;
flp.Controls.Add(beforeLabel);
requestedCountControl = new NumericUpDown();
requestedCountControl.Maximum = 1000;
requestedCountControl.Minimum = 1;
requestedCountControl.Value = 100;
flp.Controls.Add(requestedCountControl);
Label afterLabel = new Label();
afterLabel.Text = "Numbers in the Fibonacci sequence.";
afterLabel.AutoSize = true;
flp.Controls.Add(afterLabel);

goButton = new Button();
goButton.Text = "&Go";
goButton.Click += new System.EventHandler(button1_Click);
flp.Controls.Add(goButton);

outputTextBox = new TextBox();
outputTextBox.Multiline = true;
outputTextBox.ReadOnly = true;
outputTextBox.ScrollBars = ScrollBars.Vertical;
outputTextBox.Dock = DockStyle.Fill;

Controls.Add(outputTextBox);
Controls.Add(progressStatusStrip);
Controls.Add(flp);

backgroundWorker = new BackgroundWorker();
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);

}

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// This method will run on a thread other than the UI thread.
// Be sure not to manipulate any Windows Forms controls created
// on the UI thread from this method.
backgroundWorker.ReportProgress(0, "Working...");
Decimal lastlast = 0;
Decimal last = 1;
Decimal current;
if (requestedCount >= 1)
{ AppendNumber(0); }
if (requestedCount >= 2)
{ AppendNumber(1); }
for (int i = 2; i < requestedCount; ++i)
{
// Calculate the number.
checked { current = lastlast + last; }
// Introduce some delay to simulate a more complicated calculation.
System.Threading.Thread.Sleep(100);
AppendNumber(current);
backgroundWorker.ReportProgress((100 * i) / requestedCount, "Working...");
// Get ready for the next iteration.
lastlast = last;
last = current;
}

backgroundWorker.ReportProgress(100, "Complete!");
}

private delegate void AppendNumberDelegate(Decimal number);
private void AppendNumber(Decimal number)
{
if (outputTextBox.InvokeRequired)
{ outputTextBox.Invoke(new AppendNumberDelegate(AppendNumber), number); }
else
{ outputTextBox.AppendText(number.ToString("N0") + Environment.NewLine); }
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
toolStripProgressBar.Value = e.ProgressPercentage;
toolStripStatusLabel.Text = e.UserState as String;
}

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Error is OverflowException)
{ outputTextBox.AppendText(Environment.NewLine + "**OVERFLOW ERROR, number is too large to be represented by the decimal data type**"); }
toolStripProgressBar.Enabled = false;
requestedCountControl.Enabled = true;
goButton.Enabled = true;

}

private void button1_Click(object sender, EventArgs e)
{
goButton.Enabled = false;
toolStripProgressBar.Enabled = true;
requestedCount = (int)requestedCountControl.Value;
requestedCountControl.Enabled = false;
outputTextBox.Clear();
backgroundWorker.RunWorkerAsync();
}
}