ASP.NET 中使用 JavaScript 实现异步进度条

实现原理与类结构

首先，需要构建两个类：一个负责与数据源进行连接（数据层），另一个负责将数据层与页面展示关联起来（逻辑层）。

JavaScript 进度条逻辑

新建一个名为 JScsrip.js 的文件。

具体代码如下：

 
function setPgb(pgbID, pgbValue,pvalues)
{ 
if ( pgbValue <= pvalues )
{ 
if (lblObj = document.getElementById(pgbID+'_label'))
{ 
lblObj.innerHTML =Math.ceil((pgbValue/pvalues)*100) + '%'; // change the label value
} 
if ( pgbObj = document.getElementById(pgbID) )
{ 
var divChild = pgbObj.children[0];
pgbObj.children[0].style.width = Math.ceil((pgbValue/pvalues)*240);//pgbValue;
} 
window.status = "数据读取第" + pgbValue+"条，请稍候";
} 
if ( pgbValue == pvalues )
{ 
window.status = "数据读取已经完成";
proBar.style.display="none";
Table1.style.display="none";
} 
} 

CSS 样式定义

建立一个 common.css 文件

具体代码如下：

 
.bi-loading-status
{ 
/**//*position: absolute;*/
width: 250px;
padding: 1px;
overflow: hidden;
} 
.bi-loading-status .text{
white-space: nowrap;
overflow: hidden;
width: 100%;
text-overflow: ellipsis;
padding: 1px;
} 
.bi-loading-status .progress-bar {
border: 1px solid ThreeDShadow;
background: window;
height: 10px;
width: 100%;
padding: 1px;
overflow: hidden;
} 
.bi-loading-status .progress-bar div {
background: Highlight;
overflow: hidden;
height: 100%;
filter: Alpha(Opacity=0, FinishOpacity=100, Style=1, StartX=0, StartY=0, FinishX=100, FinishY=0);
} 

HTML 页面结构

建立一个 progressbar.htm 文件

具体代码如下：

 
<body topmargin="0" leftmargin="0">
<table width="100%" height="100%" ID="Table1" runat=server>
<tr>
<td align="center" valign="middle">
<DIV class="bi-loading-status" id="proBar" style=" LEFT: 425px; TOP: 278px" align="left">
<DIV class="text" id="pgbMain_label" align="left"></DIV>
<DIV class="progress-bar" id="pgbMain" align="left">
<DIV STYLE="WIDTH:5%"></DIV>
</DIV>
</DIV>
</td>
</tr>
</table>
</body>

ASP.NET 前端与后台实现

建立一个 Default.aspx 文件

前台代码如下：

 
<head>
<script language="javascript" src="JScript.js" type="text/javascript"></script>
</head>
<body >
<form id="Form1" method="post" runat="server">
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</form>
</body>

后台代码如下：

 
public partial class _Default : System.Web.UI.Page
{ 
DataSet ds;
text ts = new text();
int count = 0;
#region Page_Load
private void Page_Load(object sender, System.EventArgs e)
{ 
if (!Page.IsPostBack)
{ 
ds = Getgridview();
count = ds.Tables[0].Rows.Count;
Response.Write("count=" + count);
string strFileName = Server.MapPath("progressbar.htm");
StreamReader sr = new StreamReader(strFileName, System.Text.Encoding.Default);
string strHtml = sr.ReadToEnd();
Response.Write("<div style='align:center;valign:bottom;'>" + strHtml + "</div>");
sr.Close();
Response.Flush();
Thread thread = new Thread(new ThreadStart(ThreadProc));
thread.Start();
LoadData(ds);
// Getgridview();
//load数据
thread.Join();
} 
} 
#endregion fixedHeader
#region Getgridview
protected DataSet Getgridview()
{ 
ds = ts.QueryProcS("2009/07", "XXXX");//这个是逻辑层中的一个方法
return ds;
} 
#endregion
#region ThreadProc
private void ThreadProc()
{ 
string strScript = "<script>setPgb('pgbMain','{0}','" + count + "');</script>";
for (int i = 0; i <= count; i++)
{ 
System.Threading.Thread.Sleep(80);
Response.Write(string.Format(strScript, i));
Response.Flush();
} 
} 
#endregion LoadData
#region LoadData
private void LoadData(DataSet dds)
{ 
for (int m = 0; m < count; m++)
{ 
for (int i = 0; i < dds.Tables[0].Columns.Count; i++)
{ 
} 
} 
this.GridView1.DataSource = dds.Tables[0].DefaultView;
this.GridView1.DataBind();
} 
#endregion Web Form Designer generated code
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{ 
// 
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
// 
InitializeComponent();
base.OnInit(e);
} 
/**/ 
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{ 
//this.Load += new System.EventHandler(this.Page_Load);
} 
#endregion
} 

启动加载页面时如下图所示。

加载完后会自动显示你要显示的数据。