In this article I have explained with an example, how to perform Email address validation using Regular Expression in Windows Forms (WinForms) Application using C# and VB.Net.
Form Design
The following Form consists of one TextBox, two Labels and a Button control.
![Email Address validation using RegularExpressionValidator in C# and VB.Net]()
Namespaces
You will need to import the following namespace.
C#
using System.Text.RegularExpressions;
VB.Net
Imports System.Text.RegularExpressions
Regular Expression (Regex) to validate Email address
Regular Expression (Regex)
^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$
Explanation
Example
When the Validate Button is clicked, the value of the TextBox is validated against the Regular Expression (Regex) and if invalid, the error Label is displayed.
C#
private void OnValidate(object sender, EventArgs e)
{
lblError.Hide();
Regex regex = new Regex(@"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
if (!regex.IsMatch(txtEmail.Text.Trim()))
{
lblError.Show();
}
}
VB.Net
Private Sub OnValidate(sender As Object, e As EventArgs) Handles btnValidate.Click
lblError.Hide()
Dim regex As Regex = New Regex("^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$")
If Not regex.IsMatch(txtEmail.Text.Trim()) Then
lblError.Show()
End If
End Sub
Demo
![Email Address validation using RegularExpressionValidator in C# and VB.Net]()
Downloads
