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如何限制 FireMonkey 中的最小表单宽度？

发布于 2024-12-13 18:25:44 字数 73 浏览 1 评论 0原文

如何限制 FireMonkey 中最小表单的宽度？在 VCL 中它曾经非常简单 - 它只在表单属性中具有 Max 和 Min 约束。

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晨曦÷微暖 2024-12-20 18:25:44

未来读者请注意：

这仅适用于 XE3 以下的版本，因为 Fmx::Platform::TPlatform 类在 XE3 中已被删除。感谢@Alain Thiffault 在评论中指出。

原始帖子：

这是一个更复杂（但更优雅）的替代解决方案，定义一个完全自定义的 Form 类，您可以从中继承自己的...

unit FMX.ConstrainedForm;

interface

uses
  System.Classes, System.Types, System.UITypes, FMX.Forms, FMX.Platform, FMX.Types;

type
  TFormConstraints = class(TPersistent)
  private
    FMaxHeight: Integer;
    FMaxLeft: Integer;
    FMaxWidth: Integer;
    FMaxTop: Integer;
    FMinHeight: Integer;
    FMinLeft: Integer;
    FMinWidth: Integer;
    FMinTop: Integer;
  public
    constructor Create;
  published
    property MaxHeight: Integer read FMaxHeight write FMaxHeight default 0;
    property MaxLeft: Integer read FMaxLeft write FMaxLeft default 0;
    property MaxWidth: Integer read FMaxWidth write FMaxWidth default 0;
    property MaxTop: Integer read FMaxTop write FMaxTop default 0;
    property MinHeight: Integer read FMinHeight write FMinHeight default 0;
    property MinLeft: Integer read FMinLeft write FMinLeft default 0;
    property MinWidth: Integer read FMinWidth write FMinWidth default 0;
    property MinTop: Integer read FMinTop write FMinTop default 0;
  end;

  TConstrainedForm = class(TCustomForm)
  private
    FConstraints: TFormConstraints;
  protected
    procedure StartWindowResize; override;
    procedure StartWindowDrag; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure SetBounds(ALeft, ATop, AWidth, AHeight: Integer); override;
  published
    property Constraints: TFormConstraints read FConstraints write FConstraints;
    property BiDiMode;
    property Caption;
    property Cursor default crDefault;
    property BorderStyle default TFmxFormBorderStyle.bsSizeable;
    property BorderIcons default [TBorderIcon.biSystemMenu, TBorderIcon.biMinimize, TBorderIcon.biMaximize];
    property ClientHeight;
    property ClientWidth;
    property Left;
    property Top;
    property Margins;
    property Position default TFormPosition.poDefaultPosOnly;
    property Width;
    property Height;
    property ShowActivated default True;
    property StaysOpen default True;
    property Transparency;
    property TopMost default False;
    property Visible;
    property WindowState default TWindowState.wsNormal;
    property OnCreate;
    property OnDestroy;
    property OnClose;
    property OnCloseQuery;
    property OnActivate;
    property OnDeactivate;
    property OnResize;
    property Fill;
    property StyleBook;
    property ActiveControl;
    property StyleLookup;
    property OnPaint;
  end;

procedure Register;

implementation

{ TFormConstraints }

constructor TFormConstraints.Create;
begin
  inherited;
  FMaxHeight := 0;
  FMaxLeft := 0;
  FMaxWidth := 0;
  FMaxTop := 0;
  FMinHeight := 0;
  FMinLeft := 0;
  FMinWidth := 0;
  FMinTop := 0;
end;

{ TConstrainedForm }

constructor TConstrainedForm.Create(AOwner: TComponent);
begin
  FConstraints := TFormConstraints.Create;
  inherited;
end;

destructor TConstrainedForm.Destroy;
begin
  FConstraints.Free;
  inherited;
end;

procedure TConstrainedForm.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
begin
  if (FConstraints.FMinWidth > 0) and (AWidth < FConstraints.FMinWidth) then
    AWidth := FConstraints.FMinWidth;

  if (FConstraints.FMaxWidth > 0) and (AWidth > FConstraints.FMaxWidth) then
    AWidth := FConstraints.FMaxWidth;

  if (FConstraints.FMinHeight > 0) and (AHeight < FConstraints.FMinHeight) then
    AHeight := FConstraints.FMinHeight;

  if (FConstraints.FMaxHeight > 0) and (AHeight > FConstraints.FMaxHeight) then
    AHeight := FConstraints.FMaxHeight;

  if (FConstraints.FMinLeft > 0) and (ALeft < FConstraints.FMinLeft) then
    ALeft := FConstraints.FMinLeft;

  if (FConstraints.FMaxLeft > 0) and (ALeft > FConstraints.FMaxLeft) then
    ALeft := FConstraints.FMaxLeft;

  if (FConstraints.FMinTop > 0) and (ATop < FConstraints.FMinTop) then
    ATop := FConstraints.FMinTop;

  if (FConstraints.FMaxTop > 0) and (ATop > FConstraints.FMaxTop) then
    ATop := FConstraints.FMaxTop;

  Platform.SetWindowRect(Self, RectF(ALeft, ATop, ALeft + AWidth, ATop + AHeight));
  inherited SetBounds(ALeft, ATop, AWidth, AHeight);
end;

procedure TConstrainedForm.StartWindowDrag;
begin
  inherited;

end;

procedure TConstrainedForm.StartWindowResize;
begin
  inherited;
end;

procedure Register;
begin
  RegisterClass(TConstrainedForm);
end;

end.

将此文件存储为 FMX.ConstrainedForm.pas，将其添加到 Form 的“uses”部分，并修改表单的声明，而不是：

TForm1 = class(TForm)

它说：

TForm1 = class(TConstrainedForm)

由于缺乏自定义设计（无论如何，这是一个“快速解决方案”），然后您需要按如下方式挂钩表单的 OnCreate 事件:

procedure TForm1.FormCreate(Sender: TObject);
begin
  Constraints.MinWidth := 400;
  Constraints.MinHeight := 400;
end;

现在这个表格不允许用户将其宽度或高度设置为低于 400！

再次强调，无需对 FireMonkey 平台本身进行任何实质性更改，这是您目前可以获得的最好的版本！

Note for future readers:

This will only work for versions below XE3 because the Fmx::Platform::TPlatform class was removed in XE3. Thanks to @Alain Thiffault for pointing it out in the comments.

Original Post:

Here's a more complicated (but more elegant) alternative solution, defining an entirely custom Form class from which you can inherit your own...

unit FMX.ConstrainedForm;

interface

uses
  System.Classes, System.Types, System.UITypes, FMX.Forms, FMX.Platform, FMX.Types;

type
  TFormConstraints = class(TPersistent)
  private
    FMaxHeight: Integer;
    FMaxLeft: Integer;
    FMaxWidth: Integer;
    FMaxTop: Integer;
    FMinHeight: Integer;
    FMinLeft: Integer;
    FMinWidth: Integer;
    FMinTop: Integer;
  public
    constructor Create;
  published
    property MaxHeight: Integer read FMaxHeight write FMaxHeight default 0;
    property MaxLeft: Integer read FMaxLeft write FMaxLeft default 0;
    property MaxWidth: Integer read FMaxWidth write FMaxWidth default 0;
    property MaxTop: Integer read FMaxTop write FMaxTop default 0;
    property MinHeight: Integer read FMinHeight write FMinHeight default 0;
    property MinLeft: Integer read FMinLeft write FMinLeft default 0;
    property MinWidth: Integer read FMinWidth write FMinWidth default 0;
    property MinTop: Integer read FMinTop write FMinTop default 0;
  end;

  TConstrainedForm = class(TCustomForm)
  private
    FConstraints: TFormConstraints;
  protected
    procedure StartWindowResize; override;
    procedure StartWindowDrag; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure SetBounds(ALeft, ATop, AWidth, AHeight: Integer); override;
  published
    property Constraints: TFormConstraints read FConstraints write FConstraints;
    property BiDiMode;
    property Caption;
    property Cursor default crDefault;
    property BorderStyle default TFmxFormBorderStyle.bsSizeable;
    property BorderIcons default [TBorderIcon.biSystemMenu, TBorderIcon.biMinimize, TBorderIcon.biMaximize];
    property ClientHeight;
    property ClientWidth;
    property Left;
    property Top;
    property Margins;
    property Position default TFormPosition.poDefaultPosOnly;
    property Width;
    property Height;
    property ShowActivated default True;
    property StaysOpen default True;
    property Transparency;
    property TopMost default False;
    property Visible;
    property WindowState default TWindowState.wsNormal;
    property OnCreate;
    property OnDestroy;
    property OnClose;
    property OnCloseQuery;
    property OnActivate;
    property OnDeactivate;
    property OnResize;
    property Fill;
    property StyleBook;
    property ActiveControl;
    property StyleLookup;
    property OnPaint;
  end;

procedure Register;

implementation

{ TFormConstraints }

constructor TFormConstraints.Create;
begin
  inherited;
  FMaxHeight := 0;
  FMaxLeft := 0;
  FMaxWidth := 0;
  FMaxTop := 0;
  FMinHeight := 0;
  FMinLeft := 0;
  FMinWidth := 0;
  FMinTop := 0;
end;

{ TConstrainedForm }

constructor TConstrainedForm.Create(AOwner: TComponent);
begin
  FConstraints := TFormConstraints.Create;
  inherited;
end;

destructor TConstrainedForm.Destroy;
begin
  FConstraints.Free;
  inherited;
end;

procedure TConstrainedForm.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
begin
  if (FConstraints.FMinWidth > 0) and (AWidth < FConstraints.FMinWidth) then
    AWidth := FConstraints.FMinWidth;

  if (FConstraints.FMaxWidth > 0) and (AWidth > FConstraints.FMaxWidth) then
    AWidth := FConstraints.FMaxWidth;

  if (FConstraints.FMinHeight > 0) and (AHeight < FConstraints.FMinHeight) then
    AHeight := FConstraints.FMinHeight;

  if (FConstraints.FMaxHeight > 0) and (AHeight > FConstraints.FMaxHeight) then
    AHeight := FConstraints.FMaxHeight;

  if (FConstraints.FMinLeft > 0) and (ALeft < FConstraints.FMinLeft) then
    ALeft := FConstraints.FMinLeft;

  if (FConstraints.FMaxLeft > 0) and (ALeft > FConstraints.FMaxLeft) then
    ALeft := FConstraints.FMaxLeft;

  if (FConstraints.FMinTop > 0) and (ATop < FConstraints.FMinTop) then
    ATop := FConstraints.FMinTop;

  if (FConstraints.FMaxTop > 0) and (ATop > FConstraints.FMaxTop) then
    ATop := FConstraints.FMaxTop;

  Platform.SetWindowRect(Self, RectF(ALeft, ATop, ALeft + AWidth, ATop + AHeight));
  inherited SetBounds(ALeft, ATop, AWidth, AHeight);
end;

procedure TConstrainedForm.StartWindowDrag;
begin
  inherited;

end;

procedure TConstrainedForm.StartWindowResize;
begin
  inherited;
end;

procedure Register;
begin
  RegisterClass(TConstrainedForm);
end;

end.

Store this file as FMX.ConstrainedForm.pas, add it to your Form's "uses" section, and modify the declaration of your form so that instead of:

TForm1 = class(TForm)

it says:

TForm1 = class(TConstrainedForm)

Due to the lack of a custom designed (at this point anyway, this is a "quick solution"), you then need to hook your form's OnCreate event as follows:

procedure TForm1.FormCreate(Sender: TObject);
begin
  Constraints.MinWidth := 400;
  Constraints.MinHeight := 400;
end;

Now this form will not allow the user to set its width or height below 400!

Again, without making some substancial changes to the FireMonkey Platform itself, this is the best you're going to get for now!

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小瓶盖 2024-12-20 18:25:44

将其放置在表单的“OnResize”事件上，根据需要替换值。
当然，这不是世界上最好的解决方案，但它会帮助您渡过难关，直到重新引入这些属性！

procedure TForm1.FormResize(Sender: TObject);
begin
  if Width < 400 then
    Width := 400;
  if Height < 400 then
    Height := 400;
end;

上面的代码很容易更改为最大值或最小值的任意组合，所以玩得开心！

Place this on the form's "OnResize" event, replace the values as appropriate.
Granted, not the best solution in the world, but it'll get you by until the properties are reintroduced!

procedure TForm1.FormResize(Sender: TObject);
begin
  if Width < 400 then
    Width := 400;
  if Height < 400 then
    Height := 400;
end;

The above code is easy enough to change for any combination of maximums or minimums, so have fun!

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抱猫软卧 2024-12-20 18:25:44

LaKraven，模拟 mouseUp 事件来消除闪烁。

if (Width > maxWidth) then
begin
  Width := maxWidth;
  Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
end;

LaKraven, simulate a mouseUp event to get rid of that flickering.

if (Width > maxWidth) then
begin
  Width := maxWidth;
  Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
end;

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对不⑦ 2024-12-20 18:25:44

刚刚发现 TForm 有一个 Constraints 属性。

非常适合我，不会闪烁。

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你的背包 2024-12-20 18:25:44

另外，对于 LaKraven 关于基于 FormResize 的解决方案的回答，请使用 ClientWidth 和 ClientHeight 而不是 Width 和 Height 以防止表单拉伸。

procedure TForm1.FormResize(Sender: TObject);
begin
    if ClientWidth < 400 then
        ClientWidth := 400;
    if ClientHeight < 400 then
        ClientHeight := 400;
end;

Additionally for LaKraven's answer about FormResize based solution, use ClientWidth and ClientHeight instead of Width and Height to prevent stretching of the form.

procedure TForm1.FormResize(Sender: TObject);
begin
    if ClientWidth < 400 then
        ClientWidth := 400;
    if ClientHeight < 400 then
        ClientHeight := 400;
end;

回复收藏 0 原文

删除会话 2024-12-20 18:25:44

以下是 Sunec 答案的更新版本，以消除闪烁。

根据 MSDN Mouse_Event 已被取代，应使用 SendInput 代替：
https://learn.microsoft.com/ en-us/windows/win32/api/winuser/nf-winuser-mouse_event

uses WinApi.Windows;

procedure TForm1.FormResize(Sender: TObject);
var
  LInput: TInput;
begin
  if ClientHeight < MIN_HEIGHT then
  begin
    ClientHeight := MIN_HEIGHT;
    FillMemory(@LInput, SizeOf(LInput), 0);
    LInput.Itype := INPUT_MOUSE;
    LInput.mi.dwFlags := MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP;
    SendInput(1, LInput, SizeOf(LInput));
  end;
  if ClientWidth < MIN_WIDTH then
  begin
    ClientWidth := MIN_WIDTH;
    FillMemory(@LInput, SizeOf(LInput), 0);
    LInput.Itype := INPUT_MOUSE;
    LInput.mi.dwFlags := MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP;
    SendInput(1, LInput, SizeOf(LInput));
  end;
end;

Below is an updated version to Sunec's answer, to get rid of flickering.

According to MSDN Mouse_Event has been superseded and SendInput should be used instead:
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-mouse_event

uses WinApi.Windows;

procedure TForm1.FormResize(Sender: TObject);
var
  LInput: TInput;
begin
  if ClientHeight < MIN_HEIGHT then
  begin
    ClientHeight := MIN_HEIGHT;
    FillMemory(@LInput, SizeOf(LInput), 0);
    LInput.Itype := INPUT_MOUSE;
    LInput.mi.dwFlags := MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP;
    SendInput(1, LInput, SizeOf(LInput));
  end;
  if ClientWidth < MIN_WIDTH then
  begin
    ClientWidth := MIN_WIDTH;
    FillMemory(@LInput, SizeOf(LInput), 0);
    LInput.Itype := INPUT_MOUSE;
    LInput.mi.dwFlags := MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP;
    SendInput(1, LInput, SizeOf(LInput));
  end;
end;

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昔梦 2024-12-20 18:25:44

要总结上述内容以获得有用的答案，只需使用下面的代码：

Uses Winapi.Windows;

Procedure TForm1.FormResize(Sender: TObject);
Begin
 If ClientWidth < 400 Then
    Begin
      ClientWidth := 400;
      Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
    End;

  If ClientHeight < 400 Then
    Begin
      ClientHeight := 400;
      Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
    End;
End;

To summery the above for a useful answer just use code below:

Uses Winapi.Windows;

Procedure TForm1.FormResize(Sender: TObject);
Begin
 If ClientWidth < 400 Then
    Begin
      ClientWidth := 400;
      Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
    End;

  If ClientHeight < 400 Then
    Begin
      ClientHeight := 400;
      Mouse_Event(MOUSEEVENTF_ABSOLUTE or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
    End;
End;

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