Email Validation in Windows Application C#.Net and VB.Net

Today email is have becomes most important part of our life. So whenever we are developing any application in either in windows or web ad asking user for email id of user, so before saving the data we must validate that email id entered by user must be valid.

So in this article I will show you how you can validate the email id in a windows application using C#.Net and VB.Net.

In my previous article I have shown How to get the selected date of a MonthCalendar control in C#, Displaying More than One Month in the Windows Forms MonthCalendar Control Using C#.Net, How to Open Command Prompt Using C#.net, How to show Error & Warning Message Box in .NET | C# MessageBox.Show Examples.

So for this article first we will create a windows application. Now add the use code.

C#.Net

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Collections; namespace ProjectDemo_Windows {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }         private void button1_Click(object sender, EventArgs e)         {             int status = ValidateEmailId(textBox1.Text);             if (status == 0)             {                 MessageBox.Show("E-Mail Id expected", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);             }             else if (status == 1)             {                 MessageBox.Show("Thanks for ptoviding a valid E-mail Id. ", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);             }             else if (status == 2)             {                 MessageBox.Show("Please enter E-mail Id", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning);             }         }         /// <summary>         /// This method is used for validating email if provied by the user         /// </summary>         /// <param name="emailId"></param>         /// <returns>0 - Invalid Eail id</returns>         /// <returns>1 - Valid Email id</returns>         /// <returns>2 - Not data found</returns>         public int ValidateEmailId(string emailId)         {             /*Regular Expressions for email id*/             System.Text.RegularExpressions.Regex rEMail = new System.Text.RegularExpressions.Regex(@"^[a-zA-Z][\w\.-]{2,28}[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$");             if (emailId.Length > 0)             {                 if (!rEMail.IsMatch(emailId))                 {                     return 0;                 }                 else                 {                     return 1;                 }             }             return 2;         }     } }

In above code we have user public int ValidateEmailId(string emailId) function to validate the email id.

VB.Net

Imports System.Collections.Generic Imports System.ComponentModel Imports System.Data Imports System.Drawing Imports System.Linq Imports System.Text Imports System.Windows.Forms Imports System.Collections Namespace ProjectDemo_Windows     Partial Public Class Form1         Inherits Form         Public Sub New()             InitializeComponent()         End Sub         Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)             Dim status As Integer = ValidateEmailId(textBox1.Text)             If status = 0 Then                 MessageBox.Show("E-Mail Id expected", "Error", MessageBoxButtons.OK, MessageBoxIcon.[Error])             ElseIf status = 1 Then                 MessageBox.Show("Thanks for ptoviding a valid E-mail Id. ", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)             ElseIf status = 2 Then                 MessageBox.Show("Please enter E-mail Id", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning)             End If         End Sub         ''' <summary>         ''' This method is used for validating email if provied by the user         ''' </summary>         ''' <param name="emailId"></param>         ''' <returns>0 - Invalid Eail id</returns>         ''' <returns>1 - Valid Email id</returns>         ''' <returns>2 - Not data found</returns>         Public Function ValidateEmailId(ByVal emailId As String) As Integer             'Regular Expressions for email id             Dim rEMail As New System.Text.RegularExpressions.Regex("^[a-zA-Z][\w\.-]{2,28}[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$")             If emailId.Length > 0 Then                 If Not rEMail.IsMatch(emailId) Then                     Return 0                 Else                     Return 1                 End If             End If             Return 2         End Function     End Class End Namespace

Now run the application for final output