日期:2014-05-19  浏览次数:20412 次

js生成的值,服务端无法读取?
在A页面中有: <asp:TextBox   ReadOnly= "true "   runat=server   id= "pageid "> </asp:TextBox>
该值输入框的值我通过打开另一页面B,使用window.opener.document.getElementById( "pageid ").value=...得到.
然后关闭B,然后在A中点击按钮回送.可是在服务器中发现pageid的Text值为 " ";读取不到在A页面中显示的值.
请问这是怎么回事?



------解决方案--------------------
在以前的ASP.NET 1.x版本中,设置为ReadOnly的TextBox控件在客户端更改了值后,在服务器端仍然可以得到修改后的值,但在ASP.NET 2.0中,这种做法已经限制。这是为了提高应用程序安全性所考虑的。下面就是TextBox控件获得数据的内部方法,由此可以看出ReadOnly的限制:

protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection)
{
base.ValidateEvent(postDataKey);
string text1 = this.Text;
string text2 = postCollection[postDataKey];
if (!this.ReadOnly && !text1.Equals(text2, StringComparison.Ordinal))
{
this.Text = text2;
return true;
}
return false;
}

这里限制的只是Text属性,而没有限制提交数据的名称/值的NameValueCollection,因此,通过Request[ "表单名称 "]的方法仍然可以得到值的。下面的例子充分说明了这一点,并且提供了既使用ReadOnly,又可以通过Text属性获得值的方法:

<%@ Page Language= "C# " EnableViewState= "false " %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN " "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">

<script runat= "server ">

protected void Button1_Click(object sender, EventArgs e)
{
Response.Write( " <li> TextBox1 = " + TextBox1.Text);
Response.Write( " <li> TextBox2 = " + TextBox2.Text);
Response.Write( " <li> TextBox3 = " + TextBox3.Text);
Response.Write( " <li> Request.Form[TextBox1] = " + Request.Form[TextBox1.UniqueID]);
Response.Write( " <li> Request.Form[TextBox2] = " + Request.Form[TextBox2.UniqueID]);
Response.Write( " <li> Request.Form[TextBox3] = " + Request.Form[TextBox3.UniqueID]);
}

protected void Page_Load(object sender, EventArgs e)
{
TextBox3.Attributes.Add( "readonly ", "readonly ");
}
</script>

<script type= "text/javascript ">
// <![CDATA[
function SetNewValue()
{
document.getElementById( ' <%=TextBox1.ClientID %> ').value = "TextBox1 new Value ";
document.getElementById( ' <%=TextBox2.ClientID %> ').value = "TextBox2 new Value ";
document.getElementById( ' <%=TextBox3.ClientID %> ').value = "TextBox3 new Value ";
}
//]]>
</script>

<html xmlns= "http://www.w3.org/1999/xhtml ">
<head runat= "server ">
<title> ASP.NET 2.0中TextBox控件与ReadOnly和Enabled属性 </title>
</head>
<body>
<form id= "form1 " runat= "server ">
<span> TextBox1 ReadOnly: </span>
<asp:TextBox ID= "TextBox1 " runat= "server " ReadOnly= "True " Text= "TextBox1 Old Value "> </asp:TextBox> <br />
<span> TextBox2 Enabled: </span>
<asp:TextBox ID= "TextBox2 " runat= "server " Enabled= "False " Text= "TextBox2 Old Value "> </asp:TextBox> <br />
<span> TextBox3 ReadOnly: </span>
<asp:TextBox ID= "TextBox3 " runat= "server " Text= "TextBox3 Old Value "> </asp:TextBox> <br />
<br />