TPanel.AutoSize 不适用于特殊配置的嵌套面板

Question

在Delphi10.4.2 win-32 VCL Application Windows10中，我使用了几个嵌套TPanel:

将这些控件粘贴到空窗体上：

object Panel1: TPanel
  Left = 0
  Top = 0
  Width = 494
  Height = 299
  Align = alClient
  BevelOuter = bvNone
  TabOrder = 0
  ExplicitLeft = 40
  ExplicitTop = 140
  ExplicitWidth = 185
  ExplicitHeight = 41
  object Splitter1: TSplitter
    Left = 222
    Top = 0
    Height = 299
    Align = alRight
    Color = clSilver
    ParentColor = False
    ExplicitLeft = 280
    ExplicitTop = 112
    ExplicitHeight = 100
  end
  object CardPanel1: TCardPanel
    Left = 225
    Top = 0
    Width = 269
    Height = 299
    Align = alRight
    ActiveCard = Card1
    BevelOuter = bvNone
    Caption = 'CardPanel1'
    Ctl3D = False
    ParentCtl3D = False
    TabOrder = 0
    ExplicitLeft = 272
    ExplicitHeight = 282
    object Card1: TCard
      Left = 0
      Top = 0
      Width = 269
      Height = 299
      Caption = 'Card1'
      CardIndex = 0
      TabOrder = 0
      ExplicitLeft = 1
      ExplicitTop = 1
      ExplicitWidth = 298
      ExplicitHeight = 280
      object pnlBackSide: TPanel
        AlignWithMargins = True
        Left = 10
        Top = 10
        Width = 249
        Height = 263
        Margins.Left = 10
        Margins.Top = 10
        Margins.Right = 10
        Margins.Bottom = 0
        Align = alTop
        AutoSize = True
        Color = clBlue
        ParentBackground = False
        TabOrder = 0
        object pnlFront: TPanel
          AlignWithMargins = True
          Left = 2
          Top = 2
          Width = 245
          Height = 259
          Margins.Left = 1
          Margins.Top = 1
          Margins.Right = 1
          Margins.Bottom = 1
          Align = alClient
          AutoSize = True
          BevelOuter = bvNone
          ParentBackground = False
          TabOrder = 0
          ExplicitWidth = 274
          ExplicitHeight = 243
          object lblBlaBla: TLabel
            AlignWithMargins = True
            Left = 3
            Top = 3
            Width = 239
            Height = 13
            Align = alTop
            Alignment = taCenter
            Caption = 'BLA BLA'
            ExplicitWidth = 39
          end
          object listboxTest: TListBox
            AlignWithMargins = True
            Left = 10
            Top = 19
            Width = 225
            Height = 55
            Margins.Left = 10
            Margins.Right = 10
            Margins.Bottom = 0
            Align = alTop
            BevelInner = bvNone
            ItemHeight = 13
            TabOrder = 0
            ExplicitWidth = 254
          end
          object Button1: TButton
            AlignWithMargins = True
            Left = 10
            Top = 78
            Width = 225
            Height = 25
            Margins.Left = 10
            Margins.Top = 4
            Margins.Right = 10
            Margins.Bottom = 0
            Align = alTop
            Caption = 'Button1'
            TabOrder = 1
            ExplicitWidth = 254
          end
          object Button3: TButton
            AlignWithMargins = True
            Left = 10
            Top = 136
            Width = 225
            Height = 25
            Margins.Left = 10
            Margins.Top = 4
            Margins.Right = 10
            Margins.Bottom = 0
            Align = alTop
            Caption = 'Button3'
            TabOrder = 2
            ExplicitWidth = 254
          end
          object Button4: TButton
            AlignWithMargins = True
            Left = 10
            Top = 165
            Width = 225
            Height = 25
            Margins.Left = 10
            Margins.Top = 4
            Margins.Right = 10
            Margins.Bottom = 0
            Align = alTop
            Caption = 'Button4'
            TabOrder = 3
            ExplicitWidth = 254
          end
          object Button2: TButton
            AlignWithMargins = True
            Left = 10
            Top = 107
            Width = 225
            Height = 25
            Margins.Left = 10
            Margins.Top = 4
            Margins.Right = 10
            Margins.Bottom = 0
            Align = alTop
            Caption = 'Button2'
            TabOrder = 4
            ExplicitWidth = 254
          end
          object pnlComboBack: TPanel
            AlignWithMargins = True
            Left = 10
            Top = 194
            Width = 225
            Height = 21
            Margins.Left = 10
            Margins.Top = 4
            Margins.Right = 10
            Margins.Bottom = 4
            Align = alTop
            AutoSize = True
            BevelOuter = bvNone
            TabOrder = 5
            ExplicitWidth = 254
            object cbbTest: TComboBox
              Left = 0
              Top = 0
              Width = 225
              Height = 21
              Margins.Left = 10
              Margins.Top = 4
              Margins.Right = 10
              Margins.Bottom = 4
              Align = alClient
              Style = csDropDownList
              ItemIndex = 0
              TabOrder = 0
              Text = 'Select an item'
              Items.Strings = (
                'Select an item')
              ExplicitWidth = 254
            end
          end
        end
      end
    end
  end
end

然后运行编译的应用程序，你会得到这样的东西：

您可以看到面板 pnlBackSide 没有自动调整大小，尽管其属性 AutoSize 设置为 True。为什么？

如何使面板 pnlBackSide 自动调整大小？

Answer 1

正如 Andreas 正确观察到的，属性 pnlFront.Align = alClient 和 pnlFront.AutoSize = True 是一个逻辑困境（因为它们是冲突的）因此不能同时执行。因此，解决方案是通过在设计时将它们设置为 pnlFront.Align = alNone 和 pnlFront.AutoSize = False 来 连续地 执行它们。然后在运行时，连续执行它们：

procedure TForm1.FormCreate(Sender: TObject);
begin
  pnlFront.AutoSize := True;
  pnlFront.Align := alClient;
end;

此外，为了补偿 pnlComboBack.Margins.Bottom，还必须在设计时将 pnlBackSide.AutoSize 设置为 False，然后在运行时设置为 True -时间（按正确顺序）：

procedure TForm1.FormCreate(Sender: TObject);
begin
  pnlFront.AutoSize := True;
  pnlBackSide.AutoSize := True;
  pnlFront.Align := alClient;
end;

所以现在的结果是完美的：

TPanel.AutoSize 不适用于特殊配置的嵌套面板

TPanel.AutoSize does not work with nested panels in a special configuration

delphi

autosize

delphi-10.4-sydney

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