How to validate a textbox for range of values,correct date?

Validations

Validation controls are used to validate the form fields for valid data when it is submitted to the server.

In the previous article, we learnt about What is "CauseValidation" property and how to avoid validation on clicking of a button? How to validate two different sets of Form fields separately? In this article, we shall How to validate a textbox for range of values,correct date and How to validate a valid email address entered into the textbox.

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In case we want to validate a textbox for the specific range of values to be entered, we can follow this approach.

ASPX PAGE

Enter year between 2000 to 2010:
<asp:TextBox ID="txtRange" runat="server" /><br />
<asp:RangeValidator ID="range1" runat="server" ErrorMessage="Sorry, must be
between 2000 and 2010" ControlToValidate="txtRange" MaximumValue="2010" MinimumValue="2000"
Type="Integer" ForeColor="Red" />
<p>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" />
</p> 

In the above code snippet, we have a TextBox that must accept the value in between 2000 and 2010. To validate this range, we can use asp:RangeValidator with MaximumValue as 2010 and MinimumValue as 2000 with Type as “Integer”. This causes the TextBox to accept only values in between 2000 to 2010.

Note: The asp:RangeValitor only works if any data is entered to the TextBox, if no data is entered and button is clicked the form is submitted to the server without validation. To avoid this, we should keep asp:RequiredFieldValidator attached with the TextBox to validate.

OUTPUT

Note: Similarly Date, Double, String, Currency values can be validated for specific range.

In case we want to validate a textbox value for the correct date, we can follow this approach.

ASPX PAGE

Date of birth:
<asp:TextBox ID="txtDOB" runat="server" /><br />
<asp:RequiredFieldValidator ID="req1" runat="server" ErrorMessage="Mandatory !" ControlToValidate="txtDOB"
ForeColor="Red" />
<asp:CompareValidator ID="comp1" runat="server" ErrorMessage="Date must be in
MM/DD/YYYY format" ControlToValidate="txtDOB" Type="Date" Operator="DataTypeCheck" ForeColor="Red" />
<p>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" />
</p> 

In the above code snippet, we have a TextBox that must accept correct date. To do that we can use asp:CompareValidator with Operator as “DataTypeCheck” and Type as “Date”. We have used asp:RequiredFieldValidator to force user to enter some data into the TextBox before the form is submitted to the server.

OUTPUT

In scenarios where we want to check whether a valid email id has been entered into the TextBox or not, we can follow this approach.

ASPX PAGE

Your email:
<asp:TextBox ID="txtEmail" runat="server" Columns="50" />
<br />
<asp:RequiredFieldValidator ID="req1" runat="server" ErrorMessage="Mandatory !" ControlToValidate="txtEmail"
ForeColor="Red" />
<asp:RegularExpressionValidator ID="ReExp1" runat="server" ControlToValidate="txtEmail"
ErrorMessage="eg. abc@domain.com" ForeColor="Red" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-
.]\w+)*"></asp:RegularExpressionValidator>
<p>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="SubmitData" />
</p> 

CODE BEHIND

protected void SubmitData(object sender, EventArgs e)
{
 
}
 

In the above code snippet, we want to validate the TextBox for correct format of the email id. For that we have used asp:RegularExpressionValidator with ValidationExpression as “\w+([-+.']\w+)*@\w+([- .]\w+)*\.\w+([-.]\w+)*” that validates the TextBox data for correct email id format (eg. abc@domain.com).

We have used asp:RequiredFieldValidtor to force user to enter some data into the TextBox.

OUTPUT

Hope this article was useful. Thanks for reading.

Keep reading my forth coming articles. To read my series of articles on ASP.NET,click here.