asp.net 1.1中,有不少验证控件,大大方便了我们,但有的时候,当需要做特殊的验证时,还会觉得不够用的,于是我们可以用自定义验证控件CustomValidator,要使用这个控件,必须在服务端写相应的事件,格式如下:
Sub _FunctionName_ (sender as Object, args as ServerValidateEventArgs)
...
End Sub
其中注意两个参数
value:指示当前的CustomValidator验证的是哪一个控件
IsValid:为真时,表示页面控件已经通过验证。
举一个验证页面中文本框的输入是否为素数的例子:
1<script language="vb" runat="server">
2 Sub btnSubmit_Click(sender as Object, e as EventArgs)
3 If Page.IsValid then
4 Response.Write("<font color=""red""><i>" & txtPrimeNumber.Text & _
5 " is, indeed, a good prime number.</i></font>")
6 Else
7 Response.Write("<font color=""red""><i>" & txtPrimeNumber.Text & _
8 " is <b>not</b> a prime number.</i></font>")
9 End If
10 End Sub
11
12
13 Sub PrimeNumberCheck(sender as Object, args as ServerValidateEventArgs)
14 Dim iPrime as Integer = Cint(args.Value), iLoop as Integer, _
15 iSqrt as Integer = CInt(Math.Sqrt(iPrime))
16
17 For iLoop = 2 to iSqrt
18 If iPrime mod iLoop = 0 then
19 args.IsValid = False
20 Exit Sub
21 End If
22 Next
23
24 args.IsValid = True
25 End Sub
26 </script>
1<form method="post" runat="server">
2 Enter your favorite prime number:
3 <asp:textbox id="txtPrimeNumber" runat="server"></asp:textbox>
4
5 ```
6-- Create the CustomValidator control --
<asp:customvalidator **="" **onservervalidate="PrimeNumberCheck" controltovalidate="txtPrimeNumber" errormessage="Invalid Prime Number" id="custPrimeCheck" runat="server"></asp:customvalidator>
```
-- Create two CompareValidator controls: the first ensures that the number entered by the user is an Integer; the second makes sure it is positive. --
1 <asp:comparevalidator controltovalidate="txtPrimeNumber" display="Dynamic" errormessage="You must enter an integer value." id="compPrimeNumber" operator="DataTypeCheck" runat="server" type="Integer"></asp:comparevalidator>
2<asp:comparevalidator controltovalidate="txtPrimeNumber" display="Dynamic" errormessage="You must enter a value greater than zero." id="compPrimeNumberPositive" operator="GreaterThan" runat="server" type="Integer" valuetocompare="0"></asp:comparevalidator>
3<p><asp:button id="btnSubmit" onclick="btnSubmit_Click" runat="server" text="Submit"></asp:button>
4</p></form>
可以看到,在验证控件中, OnServerValidate="PrimeNumberCheck"中,要定义具体的onservervalidate事件
,之后,在具体的事件处理过程中,一定要返回args.isvalid的值,以价讲明是否验证成功;当然,最后要用page.isvalid属性
来进行全面验证