ASP.NET中使用自訂驗證控制項

來源:互聯網
上載者:User

  asp.net 1.1中,有不少驗證控制項,大大方便了我們,但有的時候,當需要做特殊的驗證時,還會覺得不夠用的,於是我們可以用自訂驗證控制項CustomValidator,要使用這個控制項,必須在服務端寫相應的事件,格式如下:

  Sub FunctionName(sender as Object, args as ServerValidateEventArgs)
  ...
  End Sub

  其中注意兩個參數 value:指示當前的CustomValidator驗證的是哪一個控制項 IsValid:為真時,表示頁面控制項已經通過驗證。舉一個驗證頁面中文字框的輸入是否為素數的例子:

<script language="vb" runat="server">
  Sub btnSubmit_Click(sender as Object, e as EventArgs)
  If Page.IsValid then
  Response.Write("<font color=""red""><i>" & txtPrimeNumber.Text & _
  " is, indeed, a good prime number.</i></font>")
  Else
  Response.Write("<font color=""red""><i>" & txtPrimeNumber.Text & _
  " is <b>not</b> a prime number.</i></font>")
  End If
  End Sub

  Sub PrimeNumberCheck(sender as Object, args as ServerValidateEventArgs)
  Dim iPrime as Integer = Cint(args.Value), iLoop as Integer, _
  iSqrt as Integer = CInt(Math.Sqrt(iPrime))

  For iLoop = 2 to iSqrt
  If iPrime mod iLoop = 0 then
  args.IsValid = False
  Exit Sub
  End If
  Next

  args.IsValid = True
  End Sub
  </script>

  <form method="post" runat="server">
  Enter your favorite prime number:
  <asp:textbox id="txtPrimeNumber" runat="server" />

  <%-- Create the CustomValidator control --%>
  <asp:CustomValidator runat="server" id="custPrimeCheck"
  ControlToValidate="txtPrimeNumber"
  OnServerValidate="PrimeNumberCheck"
  ErrorMessage="Invalid Prime Number" />

  <%-- Create two CompareValidator controls: the first ensures that
  the number entered by the user is an Integer; the second
  makes sure it is positive. --%>
  <asp:CompareValidator runat="server" id="compPrimeNumber"
  Operator="DataTypeCheck" Type="Integer"
  Display="Dynamic" ControlToValidate="txtPrimeNumber"
  ErrorMessage = "You must enter an integer value." />
  <asp:CompareValidator runat="server" id="compPrimeNumberPositive"
  Operator="GreaterThan" Type="Integer"
  Display="Dynamic" ValueToCompare="0"
  ControlToValidate="txtPrimeNumber"
  ErrorMessage = "You must enter a value greater than zero." />

  <p><asp:button id="btnSubmit" runat="server"
  OnClick="btnSubmit_Click" Text="Submit" />
  </form>

  可以看到,在驗證控制項中,   OnServerValidate="PrimeNumberCheck"中,要定義具體的onservervalidate事件,之後,在具體的事件處理過程中,一定要返回args.isvalid的值,以價講明是否驗證成功;當然,最後要用page.isvalid屬性來進行全面驗證。

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