VCLStringHandling (C++)

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Description

This example is a VCL Form application that shows how to handle strings in a VCL Form. The application uses basic string operations and methods to modify the Caption property of a TStaticText.

To build and test this example, create a VCL Form Application - C++, then add the next objects to the form:

  • A TStaticText control.
  • Two TPanel controls. Add the following components to the first TPanel control:
    • Two TLabel controls. Set the Caption properties to Insert characters: and Text:.
    • Two TEdit controls. Set the Name properties to textEdit and insPositionEdit.
    • Three TRadioButton controls. Set the Name properties to beginingRadio, endRadio, insPositionRadio, and respectively the Caption properties to At the begining, At the end, and At a specified position.
    • A TButton control. Set the Name property to insertButton, and the Caption property to Insert.
  • Add the following components to the first TPanel control:
    • Three TLabel controls. Set the Caption properties to Delete characters:, Position:, and Count:.
    • Three TEdit controls. Set the Name properties to delPositionEdit, countEdit, and substringEdit.
    • Two TRadioButton controls. Set the Name properties to delPositionRadio and substringRadio, and respectively the Caption properties to Specify position and Specify substring.
    • A TButton control. Set the Name property to deleteButton and the Caption property to Delete.

At this moment the form should look like in the following image.

VCLStringHandling.png

Code

Add the following code to the OnCreate event handler of the VCL Form:

// ---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender) {
	beginingRadio->Checked = true;
	delPositionRadio->Checked = true;
	staticText->Caption = "This text will be modified";
}

Add the following code to the OnClick event handler of the insertButton:

// ---------------------------------------------------------------------------
void __fastcall TForm1::insertButtonClick(TObject *Sender) {
	int position;

	if (beginingRadio->Checked) {
		staticText->Caption = textEdit->Text + staticText->Caption;
	}
	else if (endRadio->Checked) {
		staticText->Caption = staticText->Caption + textEdit->Text;
	}
	else if (insPositionRadio->Checked) {
		try {
			position = StrToInt(insPositionEdit->Text);
			staticText->Caption = staticText->Caption.Insert(textEdit->Text,
				position);
		}
		catch (Exception& e) {
			ShowMessage(e.ToString());
		}
	}
}

Add the following code to the OnClick event handler of the deleteButton:

// ---------------------------------------------------------------------------
void __fastcall TForm1::deleteButtonClick(TObject *Sender) {
	if (delPositionRadio->Checked) {
		try {
			int position, count;
			position = StrToInt(delPositionEdit->Text);
			count = StrToInt(countEdit->Text);
			staticText->Caption = staticText->Caption.Delete(position, count);
		}
		catch (Exception& e) {
			ShowMessage(e.ToString());
		}
	}
	else if (substringRadio->Checked) {
		staticText->Caption = StringReplace(staticText->Caption,
			substringEdit->Text, "", TReplaceFlags() << rfReplaceAll);
	}
}

Uses

See Also

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