Page 77 - DCAP312_WEB_TECHNOLOGIES_II

Unit 4: Advanced Server Controls

Notes
Checking to Make Sure Value Entered is of a Specific Data Type
Age:
<asp:TextBox id= “TextBox1” runat= “server” MaxLength= “3”>
</asp:TextBox>

<asp:CompareValidator id= “CompareValidator1” runat= “server”

ErrorMessage= “You must enter a number”
ControlToValidate= “TextBox1” Type= “Integer”
Operator= “DataTypeCheck”></asp:CompareValidator>
In this example, the user must enter an integer in the text box; otherwise, the
CompareValidator server control fires and displays an error message on the
page. By giving the Type property of the CompareValidator server control a
value of Integer, we ensure that the value entered in the text box conforms
to this .NET Framework data type.
We also have the option of not only comparing values against specific data
types, but also ensuring that values are valid when compared against certain
constants.

Age:
<asp:TextBox id= “TextBox1” runat= “server”></asp:TextBox>

<asp:CompareValidator id= “CompareValidator1” runat= “server”
Operator= “GreaterThan” ValueToCompare= “18”
ControlToValidate= “TextBox1” ErrorMessage= “You must be older than
18 to join” Type= “Integer”></asp:CompareValidator>

In this case, a few checks are made next to any value that the user types in the text box. The
initial is based on the Type possessions in the CompareValidator server organize. The Type
property has the value of digit, therefore any value located in the text box requirements to be
conventional to this .NET Framework data type. If the user enters a string into the text box, the
form submission is invalid. The next property is the Operator property. This property has a
value of Greater Than, meaning that for the form submission to be valid, the value entered in
the text box has to be greater than the value that is assigned to the ValueToCompare property.
For this CompareValidator server control, the ValueToCompare property has a value of 18. This
means that the value entered in the text box on the page must be an integer greater than 18. If it
does not meet these criteria, the value is considered invalid, and the CompareValidator server
control displays an error message in the browser.

In the circumstances shown in above example, we are not comparing two fields in the form;
instead, we are comparing one field against a value that we have particular in cipher. The
Operator property can contain one of the following values. The Operator property can contain
one of the following values:
• Equal
• Not Equal

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