ASP.NET - ASP.NET后台注册javascript脚本方法

注意: .NET Framewrok 1.0/1.1中的Page.RegisterStartupScript 和 Page.RegisterClientScriptBlock方法已经被弃用,这两个用于注册脚本的方法需要一组键/值对,由于方法比较复杂,很可能发生键名冲突.Page.ClientScript属性把所有的脚本注册都放在一起,使代码不容易出错

<1>使用Page.ClientScript.RegisterClientScriptBlock(注册到页面顶部)

两种构建方式:

1).RegisterClientScriptBlock(Type type,String key,String script); //类型,键,脚本

2).RegisterClientScriptBlock(Type type,String key,String script,bool addScriptTags); //类型,键,脚本,是否添加脚本标记

例子:

< ! --.aspx页面-- >

< asp:Button ID ="btnScript" runat ="server" OnClick ="btnScript_Click" Text ="点击输出javascript" />

 

<!--.aspx.cs页面-->

protected void btnScript_Click( object sender, EventArgs e)
{
                MessageBox.Show( this, "myScript", "HelloWorld!!!"); //Page对象,键名,消息.
}

/// <summary>
/// 模拟Winform的MessageBox.Show();
/// </summary>
public class MessageBox    
{
         public static void Show(System.Web.UI.Page page, string key, string Message)
        {
                 string myScript = @"alert('" + Message + "');";
                 if (!page.ClientScript.IsClientScriptBlockRegistered(key))
                {
                        page.ClientScript.RegisterClientScriptBlock(page.GetType(), key, myScript, true);
                }
        }
}

 

<2>使用Page.ClientScript.RegisterStartupScript(注册到页面底部)

两种构建方式:

1).RegisterStartupScript(Type type,String key,String script); //类型,键,脚本

2).RegisterStartupScript(Type type,String key,String script,bool addScriptTags); //类型,键,脚本,是否添加脚本标记

注意:这两种注册方法虽然只是注册部位不一样,但是区别很大.如果页面上有一些处理控件的JavaScript,应该使用RegisterStartupScript

例子:

< ! --.aspx页面-- >

< asp:Button ID ="btnScript" runat ="server" OnClick ="btnScript_Click" Text ="点击输出javascript" />

< asp:TextBox ID ="txtMessage" runat ="server" >Hello ASP.NET! </asp:TextBox>

//错误示范

//<!--.aspx.cs页面(使用RegisterClientScriptBlock报错,找不到指定控件的ID) -->

//protected void btnScript_Click(object sender, EventArgs e)
//{
//        string myScript = @"alert(document.forms[0]['txtMessage'].value);";
//        if (! Page.ClientScript.IsClientScriptBlockRegistered("MyScript"))
//        {
//                Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "MyScript", myScript, true);
//        }
//}

//正确示范

<!--.aspx.cs页面(应该使用RegisterStartupScript) -->

protected void btnScript_Click( object sender, EventArgs e)
{
         string myScript = @"alert(document.forms[0]['txtMessage'].value);";
         if (! Page.ClientScript.IsStartupScriptRegistered( "MyScript"))
        {
                Page.ClientScript.RegisterStartupScript( this.GetType(), "MyScript", myScript, true);
        }
}

<3>使用Page.ClientScript.RegisterClientScriptInclude(引用.js文件)

//C#中:

string myScript = "myJsCode.js";

Page.ClientScript.RegisterClientScriptInclude( "myKey",myScript);

//这会在ASP.NET中生成以下代码

<script scr= "myJsCode.js" type= "text/javascript"></script>

 

<4>使用回调功能(Ajax效果)

步骤:

1)在ASP.NET建立<input type='button' .../>

2)写入调用javscript

3)在.aspx.cs页面中实现ICallBackEventHandler接口

4)实现接口的两个方法:GetCallbackResult,RaiseCallbackEvent

5)在Page_Load里面注册脚本

 

例子:

< ! -- aspx页面 -- >

< script language ="javascript" type ="text/javascript" >
                function GetNumber()    
                {
                        UseCallBack(); //回调函数
                }

                //用来接受返回信息并显示
                function GetRandom(TextBox1, content)
                {
                        document.forms[0].txtMessage.value = TextBox1;
                }
</script>

< asp:TextBox ID ="txtMessage" runat ="server" > </asp:TextBox>    
< input id ="btn" type ="button" value ="GetRandom" onclick ="GetNumber()" />

注意: < asp:button >不能在这里使用

 

<!-- aspx.cs页面 -->

public partial class CallBackPage: System.Web.UI.Page,System.Web.UI.ICallbackEventHandler
{
         private string _callbackResult = null;
         protected void Page_Load( object sender, EventArgs e)
        {
                 //GetRandom是方法名, 不需要括号()
                 string reference = Page.ClientScript.GetCallbackEventReference( this, "arg", "GetRandom", "content");
                 string myScript = @"function UseCallBack(arg,content)" + "{" + reference + ";" + "}";
                Page.ClientScript.RegisterClientScriptBlock( this.GetType(), "key", myScript, true);
        }

ICallbackEventHandler 成员(实现接口) #region ICallbackEventHandler 成员(实现接口)
         string ICallbackEventHandler.GetCallbackResult()
        {
                 return _callbackResult;
        }

         void ICallbackEventHandler.RaiseCallbackEvent( string eventArgument)
        {
                Random random = new Random();
                _callbackResult = random.Next().ToString();
        }
        #endregion
}

 

Page_Load,GetCallbackResult() 写法趋于固定, 只需要换方法名即可.

RaiseCallbackEvent()方法是用来处理需要显示的数据信息. 一般调用连接数据库返回信息.