CODEWITHSUNDEEP
c#winforms
Sumit Bhattarai
Sumit Bhattarai

Reputation: 308

Validate textbox that it should contain one number and a special character

This is my design

Here Is My C# code:

 private void btnLogin_Click(object sender, EventArgs e)
  {
     if (Regex.IsMatch(txtPassword.Text, @"(!|@|#)"))
      {
      MessageBox.Show("Password Must Contain at least a special character");
       }

       else
       {
     SqlConnection con = new SqlConnection("Data Source=Sumit;Initial Catalog=BroadDB;Integrated Security=True");
    string sql = "select * from tblLogin where username=@username and password=@password";
      SqlCommand cmd = new SqlCommand(sql, con);
      cmd.Parameters.AddWithValue("@username", txtUsername.Text);
      cmd.Parameters.AddWithValue("@password", txtPassword.Text);

   SqlDataAdapter da = new SqlDataAdapter(cmd);

    DataTable dt = new DataTable();
    da.Fill(dt);

    if (dt.Rows.Count > 0)
     {
      Form2 obj = new Form2();
      obj.Show();
     }

   else
    {
      MessageBox.Show("Invalid Data");
    }
  }        
    }

How to validate that password should contain atleast a number and a special character when login button is clicked.

Upvotes: 2

Views: 2349

Answers (3)

Nick77
Nick77

Reputation: 23

Sorry, I can't comment yet, but don't you use a regex for special chars already?

  if (Regex.IsMatch(txtPassword.Text, @"(!|@|#)"))
  {
  MessageBox.Show("Password Must Contain at least a special character");
  }

If I understand your question right you could do this also with numbers or letters.

Have a look on this answered question, it could help you:

How to check if a String contains any letter from a to z?

Update

It's because you don't use a -> ! before Regex.IsMatch, so the MessageBox only Appears when the user inputs a special char, but not when he don't do it.

Try it with this one:

  if (!Regex.IsMatch(txtPassword.Text, @"(!|@|#)"))
  {
  MessageBox.Show("Password Must Contain at least a special character");
  }

Upvotes: 0

Darshan Faldu
Darshan Faldu

Reputation: 1605

try below code

if (!Regex.IsMatch(txtPassword.Text, @"(!|@|#)") || !txtPassword.Text.Any(char.IsDigit))
{
    Console.WriteLine("Password Must Contain at least a special character and digit");
}
else
{
    // DO YOUR STUFF
}

Upvotes: 1

Jurjen
Jurjen

Reputation: 1396

You can achieve this by testing the string you retrieve from the user input. For this you can best use a regex.

Regex regexPassword = new Regex( @"
  ^               // From the start of the string
  [a-zA-Z0-9!@#]+ // The string should contain some of these characters, like letters including digits and special chars      
  (<=[!@#])       // one of these should be a special character
  (<=[0-9])       // one of these should be a number
  $               // end of string
" , RegexOptions.IgnorePatternWhitespace ) ;

Then of course you can test your regex against your string as usual:

if(regexPassword.IsMatch(yourPasswordString))
{
    //Do what you want
}

Upvotes: 0

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