控制項 RangeValidator控制項主要界定輸入的值的範圍。因為有時我們要求輸入的值是要有一定範圍的，所以我們要使用RangeValidator來判斷。
在下面的這個例子中，我們將來介紹RangeValidator控制項。
請看validata5.aspx的程式內容：
<!--源檔案：form\web頁面簡介\validate5.aspx-->
<%@ Page clienttarget=downlevel %>
<html>
<center>
<title>RangeValidator控制項示範</title>
<head>
<script language="VB" runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
If (Page.IsValid) Then
lblOutput.Text = "結果正確!"
Else
lblOutput.Text = "結果不正確!"
End If
End Sub
Sub lstOperator_SelectedIndexChanged(sender As Object, e As EventArgs)
rangeVal.Type = lstType.SelectedIndex
rangeVal.Validate
End Sub
</script>
</head>
<body>
<h3><font face="Verdana">RangeValidator控制項示範</font></h3>
<p>
<form runat="server">
<table bgcolor="#eeeeee" cellpadding=10>
<tr valign="top">
<td>
<h5><font face="Verdana">輸入要驗證的值:</font></h5>
<asp:TextBox Selected id="txtComp" runat="server"/>
</td>
<td>
<h5><font face="Verdana">資料類型:</font></h5>
<asp:DropDownList id="lstType" OnSelectedIndexChanged="lstOperator_SelectedIndexChanged" runat=server>
<asp:ListItem Selected Value="String" >String</asp:ListItem>
<asp:ListItem Value="Integer" >Integer</asp:ListItem>
</asp:DropDownList>
</td>
<td>
<h5><font face="Verdana">最小值:</font></h5>
<asp:TextBox id="txtMin" runat="server" />
</td>
<td>
<h5><font face="Verdana">最大值:</font></h5>
<asp:TextBox id="txtMax" runat="server" /><p>
<asp:Button Text="驗證" ID="Button1" onclick="Button1_Click" runat="server" />
</td>
</tr>
</table>
<asp:RangeValidator id="rangeVal" Type="String" ControlToValidate="txtComp" MaximumControl="txtMax" MinimumControl="txtMin" runat="server"/>
<br>
<asp:Label id="lblOutput" Font-Name="verdana" Font-Size="10pt" runat="server" />
</form>
</body>
</center>
</html>
當我們在三個文字框中分別輸入要驗證的值，最大值，和最小值，然後按下驗證按鈕，頁面上將顯示判斷的結果。
