Exception raised when setting Text property of TEdit in custom component (Lazarus)

问题

Using: Lazarus 1.2.0; Windows 32-bit application

I have created a custom component derived from TCustomPanel and contains some TEdit controls.

At runtime, when I try to set the Text property of an edit control in my component, I get a runtime error.

This is the error:

Project project1 raised exception class 'External: SIGSEGV'. 

In file '.\include\control.inc' at line 3246:
GetTextMethod := TMethod(@Self.GetTextBuf);

I Googled and could not find anybody else reporting this error specifically when setting the Text property of TEdit.

This leads me to believe that I did something wrong when writing the component. Please check my code and point out what is wrong and how to fix it. TIA!

Code follows:

unit uEditPanel;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, LResources, Forms, Controls, Graphics, Dialogs, ExtCtrls, StdCtrls;

type

  { TEditPanel }

  TEditPanel = class(TCustomPanel)
    Edit0: TCustomEdit;
    Edit1: TCustomEdit;
    Edit2: TCustomEdit;
    Edit3: TCustomEdit;
    Edit4: TCustomEdit;

  private
    { Private declarations }
    function GetEdit0Text: string;
    procedure SetEdit0Text(AText: string);
    function GetEdit1Text: string;
    procedure SetEdit1Text(AText: string);
    function GetEdit2Text: string;
    procedure SetEdit2Text(AText: string);
    function GetEdit3Text: string;
    procedure SetEdit3Text(AText: string);
    function GetEdit4Text: string;
    procedure SetEdit4Text(AText: string);
  protected
    { Protected declarations }
  public
    { Public declarations }
    procedure CreateWnd; override;
  published
    { Published declarations }
    property Edit0Text: string read GetEdit0Text write SetEdit0Text;
    property Edit1Text: string read GetEdit1Text write SetEdit1Text;
    property Edit2Text: string read GetEdit2Text write SetEdit2Text;
    property Edit3Text: string read GetEdit3Text write SetEdit3Text;
    property Edit4Text: string read GetEdit4Text write SetEdit4Text;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Standard', [TEditPanel]);
end;

{ TEditPanel }

function TEditPanel.GetEdit0Text: string;
begin
  Result := Edit0.Text;
end;

procedure TEditPanel.SetEdit0Text(AText: string);
begin
  Edit0.Text := AText;
end;

function TEditPanel.GetEdit1Text: string;
begin
  Result := Edit1.Text;
end;

procedure TEditPanel.SetEdit1Text(AText: string);
begin
  Edit1.Text := AText;
end;

function TEditPanel.GetEdit2Text: string;
begin
  Result := Edit2.Text;
end;

procedure TEditPanel.SetEdit2Text(AText: string);
begin
  Edit2.Text := AText;
end;

function TEditPanel.GetEdit3Text: string;
begin
  Result := Edit3.Text;
end;

procedure TEditPanel.SetEdit3Text(AText: string);
begin
  Edit3.Text := AText;
end;

function TEditPanel.GetEdit4Text: string;
begin
  Result := Edit4.Text;
end;

procedure TEditPanel.SetEdit4Text(AText: string);
begin
  Edit4.Text := AText;
end;

procedure TEditPanel.CreateWnd;
begin
  inherited CreateWnd;

  Caption := EmptyStr;
  Height := 117;
  Width := 289;
  BevelOuter := bvNone;
  ClientHeight := 117;
  ClientWidth := 289;

  Edit0 := TCustomEdit.Create(Self);
  Edit1 := TCustomEdit.Create(Self);
  Edit2 := TCustomEdit.Create(Self);
  Edit3 := TCustomEdit.Create(Self);
  Edit4 := TCustomEdit.Create(Self);

  Edit0.Left := 0;
  Edit0.Height := 21;
  Edit0.Top := 0;
  Edit0.Width := 288;
  //Edit0.BorderStyle := bsNone;
  Edit0.TabOrder := 0;

  Edit1.Left := 0;
  Edit1.Height := 21;
  Edit1.Top := 24;
  Edit1.Width := 288;
  // Edit1.BorderStyle := bsNone;
  Edit1.TabOrder := 1;
  Edit1.Font.Color := clGray;

  Edit2.Left := 0;
  Edit2.Height := 21;
  Edit2.Top := 48;
  Edit2.Width := 288;
  //  Edit2.BorderStyle := bsNone;
  Edit2.TabOrder := 2;
  Edit2.Font.Color := clGray;

  Edit3.Left := 0;
  Edit3.Height := 21;
  Edit3.Top := 72;
  Edit3.Width := 288;
  //Edit3.BorderStyle := bsNone;
  Edit3.TabOrder := 3;
  Edit3.Font.Color := clGray;

  Edit4.Left := 0;
  Edit4.Height := 21;
  Edit4.Top := 96;
  Edit4.Width := 288;
  //Edit4.BorderStyle := bsNone;
  Edit4.TabOrder := 4;
  Edit4.Font.Color := clGray;

  Edit0.Parent := Self;
  Edit1.Parent := Self;
  Edit2.Parent := Self;
  Edit3.Parent := Self;
  Edit4.Parent := Self;

  Edit0.SetSubComponent(True);
  Edit1.SetSubComponent(True);
  Edit2.SetSubComponent(True);
  Edit3.SetSubComponent(True);
  Edit4.SetSubComponent(True);
end;

end.

回答1:

Solved. Answer posted by user JuhaManninen on the Lazarus support forum:

"You have no constructor in your class. Replace CreateWnd with a constructor."

来源：https://stackoverflow.com/questions/23040177/exception-raised-when-setting-text-property-of-tedit-in-custom-component-lazaru