ASP.NET中使用自定义验证控件(原作)

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

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