While the ErrorFormatter adds formatting around the error message, you may want changes within the error message. There are two ways to customize the error message itself:

• Tokens that display the Label property, various other design time properties, and runtime values.
• Style sheets applied around those tokens.

Both are shown here.

Demo

This example shows a textbox with label. The validator is a TextLengthValidator that compares the number of characters in the textbox to a minimum and maximum. For this demo, the minimum is 5 and maximum is 10. The ErrorMessage property contains this value:

Enter any number of characters above 10 or below 5 and tab off to see the error message.

ASP.NET Syntax for this demo

<asp:Label id=Label1 runat="server">Field Label</asp:Label>
<asp:TextBox id=TextBox1 runat="server" Width="323px"></asp:TextBox>
<des:TextLengthValidator id=TextLengthValidator1 runat="server" 
   ControlIDToEvaluate="TextBox1" Minimum="5" Maximum="10" Label-LabelControlID="Label1"
   ErrorMessage="You have entered {COUNT} {COUNT:character:characters} on {LABEL}. Please enter between {MINIMUM} and {MAXIMUM}." >
   <ErrorFormatterContainer>
      <des:TextErrorFormatter Display="Dynamic"></des:TextErrorFormatter>
   </ErrorFormatterContainer>
</des:TextLengthValidator>

Style sheet classes that affect tokens

.DESVALLabelToken
{
   font-weight: bold;
}
.DESVALRuntimeToken
{
   color: Maroon;
}
.DESVALPropertyToken
{
   text-decoration: underline;
}