Using Regular Expression on C++Builder FireMonkey Application

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Here another C++ example showing how to use the RTL regular expression on C++Builder FireMonkey Application.

This example  validate a string content based on four different regular expression, which are:

  • Checks if the given text is a validate e-mail address
  • Checks if the given text contains a valid IP address
  • Checks if the given text is a valid date (dd-mm-yyyy)
  • Checks if the given text is a valid date (mm-dd-yyyy)

The follow code shows the four regular expressions used by this application.

void __fastcall TForm1::lbRegExpChange(TObject *Sender) {
	switch (lbRegExp->ItemIndex) {
	case 0:
		lbType->Text = "E-mail for validation";

		MemoRegEx->Text =
			"^((?>[a-zA-Z\d!#$%&''*+\\-/=?^_`{|}~]+\\x20*" "|\"((?=[\\x01-\\x7f])[^\"\\\\]|\\\\[\\x01-\\x7f])*\"\\"
			"x20*)*(?\.?[a-zA-Z\d!" "#$%&''*+\\-/=?^_`{|}~]+)+|\"\"((?=[\\x01-\\x7f])"
			"[^\"\\\\]|\\\\[\\x01-\\x7f])*\")@(((?!-)[a-zA-Z\\d\\" "-]+(?)$";

		break;
	case 1: {
			// Accept IP address between 0..255
			lbType->Text = "IP address for validation (0..255)";
			MemoRegEx->Text =
				"\\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\" ".(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\."
				"(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\b";
			break;

		}
	case 2: {
			// Data interval format mm-dd-yyyy
			lbType->Text =
				"Date in mm-dd-yyyy format from between 01-01-1900 and 12-31-2099";
			MemoRegEx->Text =
				"^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[" "01])[- /.](19|20)\\d\\d$";
			break;

		}
	case 3: {
			// Data interval format mm-dd-yyyy
			lbType->Text =
				"Date in dd-mm-yyyy format from between 01-01-1900 and 31-12-2099";
			MemoRegEx->Text =
				"^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[01" "2])[- /.](19|20)\\d\\d$";
			break;

		}
	}
	EditTextChangeTracking(EditText);

}

To execute the validation you can use the method TRegExp::IsMatch as you can see bellow:

void __fastcall TForm1::EditTextChangeTracking(TObject *Sender) {
       // EditText contain the string value and MemoRegEx the regular expression
	if (TRegEx::IsMatch(EditText->Text, MemoRegEx->Text)) {
		SEResult->ShadowColor = TAlphaColors::Green;
	}
	else
		SEResult->ShadowColor = TAlphaColors::Red;

}

Since this is a FireMonkey Application, I used a Shadow Effect to show if the Edit box value is valid or not (Green=valid / Red=invalid). The following image shows what happen when you input a invalid e-mail address on Windows and Mac.

Now the results when you provide the correct e-mail address.

You can download the source code from here or just update your local RAD Studio XE2 samples folder from our RAD Studio SVN repository.


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