Delphi/Pascal:使用其他原型重载构造函数 [英] Delphi/pascal: overloading a constructor with a different prototype

问题描述

我正在尝试使用

1. 在某些情况下的特殊构造函数，并且
2. 将与当前代码保持兼容性的默认构造函数.

这是我现在拥有的代码:

This is the code I have now:

interface
  TfrmEndoscopistSearch = class(TForm)
  public
    /// original constructor kept for compatibility
    constructor Create(AOwner : TComponent); overload; override;
    /// additional constructor allows for a caller-defined base data set
    constructor Create(AOwner : TComponent; ADataSet : TDataSet; ACaption : string = ''); overload;
  end;

这似乎可行，但我总是收到编译器警告:

It seems to work, but I always get the compiler warning:

[Warning] test.pas(44): Method 'Create' hides virtual method of base type 'TCustomForm'

• 添加超载；"在第二个构造函数之后将无法编译. "[错误] test.pas(44):创建"的声明与之前的声明不同."
• 使第二个构造函数成为类函数，编译时不会出现任何错误或警告，但会在运行时死于访问冲突(所有成员var均为nil).

推荐答案

尝试在第二个overload之前添加reintroduce，如下所示:

Try adding reintroduce before the second overload, like this:

  TfrmEndoscopistSearch = class(TForm)
  public
    /// original constructor kept for compatibility
    constructor Create(AOwner : TComponent); overload; override;
    /// additional constructor allows for a caller-defined base data set
    constructor Create(AOwner : TComponent; ADataSet : TDataSet; ACaption : string = ''); reintroduce; overload;
  end;

这是在Turbo Delphi中编译的.我需要public进行编译，因为published方法的重载受到限制.

This compiles in Turbo Delphi. I needed the public to make it compile because overloading of published methods is restricted.

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