Validating a Registration Form Using Regular Expression in C#
Today, I will teach you how to validate a Registration Form using Regular Expressions in C#. Regular Expression contains the formated rules and check lengths to validate the inputs of a certain texbox. This method is very useful because it will help you restrict each fields in the form.
Let’s get started:
Open Microsoft Visual Studio 2008 and create new Windows Form Application for C#. Then, do the following design of a Form as follows.
Go to the Solution Explorer, click the “View Code” to make the code editor appear.
In the code editor, import the regural expression library above the namespace.
using System.Text.RegularExpressions;
After that, create the following method inside the class. These methods are use to format the specific fields using the correct patern.
//Method for validating email address
private static Regex Email_Address()
{
string Email_Pattern = @"^(?!\.)(""([^""\r\\]|\\[""\r\\])*""|"
+ @"([-a-z0-9!#$%&'*+/=?^_`{|}~]|(?<!\.)\.)*)(?<!\.)"
+ @"@[a-z0-9][\w\.-]*[a-z0-9]\.[a-z][a-z\.]*[a-z]$";
return new Regex(Email_Pattern, RegexOptions.IgnoreCase);
}
//Method for string only validation
private static Regex StringOnly()
{
string StringAndNumber_Pattern = "^[a-zA-Z]";
return new Regex(StringAndNumber_Pattern, RegexOptions.IgnoreCase);
}
//Method for numbers only validation
private static Regex NumbersOnly()
{
string StringAndNumber_Pattern = "^[0-9]*$";
return new Regex(StringAndNumber_Pattern, RegexOptions.IgnoreCase);
}
//Method for validating password
private static Regex ValidPassword()
{
string Password_Pattern = "(?!^[0-9]*$)(?!^[a-zA-Z]*$)^([a-zA-Z0-9]{8,15})$";
return new Regex(Password_Pattern, RegexOptions.IgnoreCase);
}
Go back to the design view, double click the button and do the following code for the validation of the registration form.
//it validate all textboxes when the button clicked
private void button1_Click(object sender, EventArgs e)
{
//for firstname
if (Valid_Fname.IsMatch(txtfName.Text) != true)
{
MessageBox.Show("Firstname accepts only alphabetical characters", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtfName.Focus();
return;
}
//for Lastname
if (Valid_Lname.IsMatch(txtLname.Text) != true)
{
MessageBox.Show("Lastname accepts only alphabetical characters", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtLname.Focus();
return;
}
//for Address
if (txtAdd.Text == "")
{
MessageBox.Show("Address cannot be empty!", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtAdd.Focus();
return;
}
//for Contacts
if (Valid_Contact.IsMatch(txtContact.Text) != true)
{
MessageBox.Show("Contact accept numbers only.", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtContact.Focus();
return;
}
//for username
if (txtuname.Text == "")
{
MessageBox.Show("Username cannot be empty!", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtuname.Focus();
return;
}
//for password
if (Valid_Password.IsMatch(txtPass.Text) != true)
{
MessageBox.Show("Password must be atleast 8 to 15 characters. It contains atleast one Upper case and numbers.", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
txtPass.Focus();
return;
}
//for Email Address
if (Valid_Email.IsMatch(txtEmail.Text) != true)
{
MessageBox.Show("Invalid Email Address!","Invalid",MessageBoxButtons.OK ,MessageBoxIcon.Exclamation );
txtEmail.Focus();
return;
}
//success message
MessageBox.Show("You are now successfully registered.");
//hidding all object in the form
foreach(Control txt in this.Controls)
{
if (txt is Control)
{
txt.Visible = false;
}
}
}
Output:
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Email – [email protected]
Mobile No. – 09305235027 – tnt
| ABOUT PROJECT | PROJECT DETAILS |
|---|---|
| Project Name : | Validating a Registration Form Using Regular Expression in C# |
| Project Platform : | C# |
| Programming Language Used: | C# Programming Language |
| Developer Name : | itsourcecode.com |
| IDE Tool (Recommended): | Visual Studio 2019 |
| Project Type : | Desktop Application |
| Database: | None |
| Upload Date and Time: | June 18, 2016- 6:49 am |
