.NET 2.0之使用JavaScript处理Pages和Server Controls
1.使用 Page.ClientScript.RegisterClientScriptBlock
Listing 4-10: Using the RegisterClientScriptBlock method
VB
<%@ Page Language=”VB” %>
<script runat=”server”>
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim myScript As String = “function AlertHello() { alert(‘Hello ASP.NET’); }”
Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), “MyScript”, _
myScript, True)
End Sub
</script>
<html xmlns=”http://www.w3.org/1999/xhtml” >
<head runat=”server”>
<title>Adding JavaScript</title>
</head>
<body>
<form id=”form1” runat=”server”>
<div>
<asp:Button ID=”Button1” Runat=”server” Text=”Button”
OnClientClick=”AlertHello()” />
</div>
</form>
</body>
</html>
c#
<%@ Page Language=”C#” %>
<script runat=”server”>
protected void Page_Load(object sender, EventArgs e)
{
string myScript = @”function AlertHello() { alert(‘Hello ASP.NET’); }”;
Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
“MyScript”, myScript, true);
}
</script>
运行结果如下：
<html xmlns=”http://www.w3.org/1999/xhtml” >
<head><title>
Adding JavaScript
</title></head>
<body>
<form method=”post” action=”JavaScriptPage.aspx” id=”form1”>
<div>
<input type=”hidden” name=”__VIEWSTATE”
value=”/wEPDwUKMTY3NzE5MjIyMGRkiyYSRMg+bcXi9DiawYlbxndiTDo=” />
</div>
<script type=”text/javascript”>
<!--
function AlertHello() { alert(‘Hello ASP.NET’); }// -->
</script>
<div>
<input type=”submit” name=”Button1” value=”Button” onclick=”AlertHello();”
id=”Button1” />
</div>
</form>
</body>
</html>
2.使用Page.ClientScript.RegisterStartupScript
RegisterStartupScript方法与RegisterClientScriptBlock方法最大的不同是：RegisterStartupScript 把script放置在ASP.NET page的底部，而RegisterClientScriptBlock把script放置在ASP.NET page的顶部。
如果你的页面中有如下代码：
<asp:TextBox ID=”TextBox1” Runat=”server”>Hello ASP.NET</asp:TextBox>
Listing 4-11: Improperly using the RegisterClientScriptBlock method
VB
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim myScript As String = “alert(document.forms[0][‘TextBox1’].value);”
Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), “myKey”, myScript, _
True)
End Sub
c#
protected void Page_Load(object sender, EventArgs e)
{
string myScript = @”alert(document.forms[0][‘TextBox1’].value);”;
Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
“MyScript”, myScript, true);
}
此页面运行时会报错，原因是JavaScript function先于text box被安放于浏览器。因此JavaScript function找不到TextBox1。
Listing 4-12: Using the RegisterStartupScript method
VB
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim myScript As String = “alert(document.forms[0][‘TextBox1’].value);”
Page.ClientScript.RegisterStartupScript(Me.GetType(), “myKey”, myScript, _
True)
End Sub
c#
protected void Page_Load(object sender, EventArgs e)
{
string myScript = @”alert(document.forms[0][‘TextBox1’].value);”;
Page.ClientScript.RegisterStartupScript(this.GetType(),
“MyScript”, myScript, true);
}
这段代码把JavaScript function放置于ASP.NET page底部，因此JavaScript运行时它能找到TextBox1。
3.使用Page.ClientScript.RegisterClientScriptInclude
许多开发者把JavaScript放置在.js文件中，使用RegisterClientScriptInclude方法可以注册.js文件中的JavaScript。
Listing 4-13: Using the RegisterClientScriptInclude method
VB
Dim myScript As String = “myJavaScriptCode.js”
Page.ClientScript.RegisterClientScriptInclude(“myKey”, myScript)
c#
string myScript = “myJavaScriptCode.js”
Page.ClientScript.RegisterClientScriptInclude(“myKey”, myScript);
这将在ASP.NET页面产生如下结构：
<script src=”myJavaScriptCode.js” type=”text/javascript”></script>
Listing 4-10: Using the RegisterClientScriptBlock method
VB
<%@ Page Language=”VB” %><script runat=”server”>Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim myScript As String = “function AlertHello() { alert(‘Hello ASP.NET’); }”
Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), “MyScript”, _myScript, True)End Sub</script><html xmlns=”http://www.w3.org/1999/xhtml” ><head runat=”server”><title>Adding JavaScript</title></head><body><form id=”form1” runat=”server”><div><asp:Button ID=”Button1” Runat=”server” Text=”Button”OnClientClick=”AlertHello()” /></div></form></body></html><%@ Page Language=”C#” %><script runat=”server”>protected void Page_Load(object sender, EventArgs e){
string myScript = @”function AlertHello() { alert(‘Hello ASP.NET’); }”;Page.ClientScript.RegisterClientScriptBlock(this.GetType(),“MyScript”, myScript, true);}</script>运行结果如下：
<html xmlns=”http://www.w3.org/1999/xhtml” ><head><title>Adding JavaScript</title></head><body><form method=”post” action=”JavaScriptPage.aspx” id=”form1”><div><input type=”hidden” name=”__VIEWSTATE”value=”/wEPDwUKMTY3NzE5MjIyMGRkiyYSRMg+bcXi9DiawYlbxndiTDo=” /></div><script type=”text/javascript”><!--function AlertHello() { alert(‘Hello ASP.NET’); }// --></script><div><input type=”submit” name=”Button1” value=”Button” onclick=”AlertHello();”id=”Button1” /></div></form></body></html>2.使用Page.ClientScript.RegisterStartupScript
RegisterStartupScript方法与RegisterClientScriptBlock方法最大的不同是：RegisterStartupScript 把script放置在ASP.NET page的底部，而RegisterClientScriptBlock把script放置在ASP.NET page的顶部。
如果你的页面中有如下代码：
<asp:TextBox ID=”TextBox1” Runat=”server”>Hello ASP.NET</asp:TextBox>Listing 4-11: Improperly using the RegisterClientScriptBlock method
VB
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)Dim myScript As String = “alert(document.forms[0][‘TextBox1’].value);”Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), “myKey”, myScript, _True)End Subprotected void Page_Load(object sender, EventArgs e){string myScript = @”alert(document.forms[0][‘TextBox1’].value);”;Page.ClientScript.RegisterClientScriptBlock(this.GetType(),“MyScript”, myScript, true);}Listing 4-12: Using the RegisterStartupScript method
VB
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)Dim myScript As String = “alert(document.forms[0][‘TextBox1’].value);”Page.ClientScript.RegisterStartupScript(Me.GetType(), “myKey”, myScript, _True)End Subprotected void Page_Load(object sender, EventArgs e){string myScript = @”alert(document.forms[0][‘TextBox1’].value);”;Page.ClientScript.RegisterStartupScript(this.GetType(),“MyScript”, myScript, true);}3.使用Page.ClientScript.RegisterClientScriptInclude
许多开发者把JavaScript放置在.js文件中，使用RegisterClientScriptInclude方法可以注册.js文件中的JavaScript。
Listing 4-13: Using the RegisterClientScriptInclude method
VB
Dim myScript As String = “myJavaScriptCode.js”Page.ClientScript.RegisterClientScriptInclude(“myKey”, myScript)string myScript = “myJavaScriptCode.js”Page.ClientScript.RegisterClientScriptInclude(“myKey”, myScript);<script src=”myJavaScriptCode.js” type=”text/javascript”></script>
