IValidator.ErrorMessage Property

Reference

Definition

Namespace:: System.Web.UI

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

When implemented by a class, gets or sets the error message text generated when the condition being validated fails.

public:
 property System::String ^ ErrorMessage { System::String ^ get(); void set(System::String ^ value); };

public string ErrorMessage { get; set; }

member this.ErrorMessage : string with get, set

Public Property ErrorMessage As String

Property Value

String

The error message to generate.

Examples

Important

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>

<!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="VB" runat="server">

         Sub Button_Click(sender As [Object], e As EventArgs)
            ' Generating a random number.
            Dim rand_s As New Random()
            myCompareValidate.ValueToCompare = rand_s.Next(1, 10).ToString()

            ' Set the ErrorMessage.
            myCompareValidate.ErrorMessage = "Try Again!!"
            myCompareValidate.Validate()

            ' Check for Validity of control.
            If myCompareValidate.IsValid And myTextBox.Text <> "" Then
               labelOutput.Text = "You guessed correctly!!"
               labelOutput.ForeColor = System.Drawing.Color.Blue
            Else
               labelOutput.Text = "You guessed poorly"
               labelOutput.ForeColor = System.Drawing.Color.Black
            End If

            labelOutput.Text += "<br /><br />" + "The number is: " + _
               myCompareValidate.ValueToCompare
         End Sub 'Button_Click

  </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>

Remarks

ASP.NET developers access this property declaratively in the opening tag of a validation server control. For more information, see Validation Server Control Syntax.

Applies to

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