RangeValidator.EvaluateIsValid Method

This method supports the .NET Framework infrastructure and is not intended to be used directly from your code.

Determines whether the content in the input control is valid.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

protected:
virtual bool EvaluateIsValid () override
protected boolean EvaluateIsValid ()
protected override function EvaluateIsValid () : boolean

Return Value

true if the control is valid; otherwise, false.

The following code example demonstrates how to override the EvaluateIsValid method in a custom server control so that it always validates that the value exists and is within the maximum and minimum values specified for the RangeValidator.

No code example is currently available or this language may not be supported.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom RangeValidator - EvaluateIsValid - VJ# Example</title>
    <script runat="server">
        void ButtonClick(Object sender, EventArgs e)
        {
            if (get_Page().get_IsValid()) {
                Label1.set_Text("Page is valid.");
            }
            else {
                Label1.set_Text("Page is not valid!!");
            }
        } //ButtonClick
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom RangeValidator - EvaluateIsValid - VJ# Example</h3>

      Enter a number from 1 to 10:<br>
      <asp:TextBox id="TextBox1" Runat="server" />

      <aspSample:CustomRangeValidatorEvaluateIsValid 
        id="RangeValidator1" 
        runat="server" 
        ControlToValidate="TextBox1" 
        MinimumValue="1" 
        MaximumValue="10" 
        Type="Integer" 
        EnableClientScript="false" 
        Text="The value must be from 1 to 10!" />
        
      <br>
      <br>
      <asp:Button id="Button1" Text="Submit" OnClick="ButtonClick" runat="server" /><br>
      <br>

      <asp:Label id="Label1" runat="server" />
    </form>
  </body>
</HTML>
...package Samples.AspNet.JSL.Controls; 

public class CustomRangeValidatorEvaluateIsValid
    extends System.Web.UI.WebControls.RangeValidator
{
    protected boolean EvaluateIsValid()
    {
        // Get the value of the control to validate.
        String controlValue = GetControlValidationValue(get_ControlToValidate());
        // If no value was entered, show the validation error by returning false.
        if (controlValue.Trim().get_Length() == 0) {
            return false;
        }
        // Compare the ControlToValidate's value against the 
        // minimum and maximum values.
        return Compare(controlValue, this.get_MinimumValue(), 
            System.Web.UI.WebControls.ValidationCompareOperator.
            GreaterThanEqual,this.get_Type()) && Compare(controlValue, 
            this.get_MaximumValue(),System.Web.UI.WebControls.
            ValidationCompareOperator.LessThanEqual,this.get_Type());
    } //EvaluateIsValid
} //CustomRangeValidatorEvaluateIsValid

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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