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IValidator.Validate Method

When implemented by a class, evaluates the condition it checks and updates the IsValid property.

Namespace:  System.Web.UI
Assembly:  System.Web (in System.Web.dll)

void Validate()

Security noteSecurity Note

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>IValidator Example demonstrating IsValid & ErrorMessage</title>
<script language="C#" runat="server">

     void Button_Click(Object sender, EventArgs e)
     {
        // Generating the random number.
        Random rand_s = new Random();
        myCompareValidate.ValueToCompare = rand_s.Next(1, 10).ToString();

        // Setting the ErrorMessage.
        myCompareValidate.ErrorMessage="Try Again!!";
        myCompareValidate.Validate();

        // Check for Validity of control.
        if ((myCompareValidate.IsValid) && (myTextBox.Text != ""))
        {
           labelOutput.Text = "You guessed correctly!!";
           labelOutput.ForeColor = System.Drawing.Color.Blue;
        }
        else
        {
           labelOutput.Text =  "You guessed poorly";
           labelOutput.ForeColor = System.Drawing.Color.Black;
        }

        labelOutput.Text += "<br /><br />" + "The number is: " +
           myCompareValidate.ValueToCompare;
     }

  </script>
</head>
    <body>
      <form runat="server" id="myForm">
        <h3>IValidator Example demonstrating IsValid & ErrorMessage</h3>
        <h5>Guess!! a number between 1 and 10 :</h5>
        <asp:TextBox id="myTextBox" runat="server" />
        <asp:CompareValidator id="myCompareValidate"
             ControlToValidate="myTextBox" ValueToCompare="0"
             EnableClientScript="False" Type="Integer" Text="*"
             runat="server" />
        <br />
        <asp:Button Text="Submit" OnClick="Button_Click" runat="server" />
        <br />
        <asp:Label id="labelOutput" runat="server" />
        <br />
        <asp:ValidationSummary id="Summary1" runat="server" />
     </form>
  </body>
</html>

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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