小编RM.*_*RM.的帖子

在Delphi XE2中,如果我在项目管理器中选择一个文件,则Object Inspector会显示该文件的属性.什么是"设计类"属性以及如何使用它？

我想将标准窗口信息(和警告和错误)图标绘制到pagecontrol的选项卡的索引.但是,如果窗口背景颜色不是白色,则结果看起来很糟糕.

program Project111;

uses
  Vcl.Forms,
  Vcl.Controls,
  Vcl.Graphics,
  Winapi.Windows,
  Vcl.ComCtrls,
  Vcl.ImgList;

{$R *.res}

var
  mainForm: TForm;
  imageList: TImageList;
  icon: TIcon;
  pageControl: TPageControl;
  tabSheet: TTabSheet;
begin
  Application.Initialize;
  Application.MainFormOnTaskbar := True;

  Application.CreateForm(TForm, mainForm);

  imageList := TImageList.Create(mainForm);
  imageList.ColorDepth := cd32bit;
  icon := TIcon.Create;
  try
    icon.Handle := LoadImage( 0, IDI_INFORMATION, IMAGE_ICON, 16, 16, {LR_DEFAULTSIZE or} LR_SHARED );
    imageList.AddIcon(icon);
  finally
    icon.Free;
  end;

  pageControl := TPageControl.Create(mainForm);
  pageControl.Parent := mainForm;
  pageControl.Images := imageList;

  tabSheet := TTabSheet.Create(mainForm);
  tabSheet.Parent := pageControl;
  tabSheet.PageControl := pageControl;
  tabSheet.ImageIndex := 0;

  Application.Run;
end.

这是一个截图: …

我想设置表达式树中引用的属性值。

using System;
using System.Diagnostics;
using System.Linq.Expressions;
using System.Reflection;

namespace ConsoleApp8
{
    class TestObject
    {
        public double X { get; set; }
    }

    class Program
    {
        static Action<double> GetSetterForX(Expression<Func<double>> expression)
        {
            var body = expression.Body;
            var operand = body as MemberExpression;
            var propertyInfo = (PropertyInfo) (operand.Member);
            var setter = propertyInfo.GetSetMethod(true);

            // At this point I have the setter. But how do I get access to the testObject?

            return null;
        }

        static void Main(string[] args)
        {
            var testObject = new TestObject(); …

我试图在TEnumerator中公开构建私有静态数组.

Delphi本身允许直接枚举静态数组(见下文),所以我怀疑Delphi在后台为静态数组创建一个枚举器,我希望我能够在GetEnumerator方法中创建和公开相同的枚举器.

(我使用的是Delphi XE2).

program Project6;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  System.Generics.Collections;

type
  TMyEnum = (meA, meB);

  TMyClass = class
  private
    FItems: array[TMyEnum] of Integer;
  protected
  public
    function GetEnumerator: TEnumerator<Integer>;
  end;

{ TMyClass }

function TMyClass.GetEnumerator: TEnumerator<Integer>;
begin
  // What is the simplies way of creating this enumerator?
end;

var
  myObj: TMyClass;
  i: Integer;

begin
  myObj := TMyClass.Create;
  try
    // This works but only in the same unit
    for i in myObj.FItems do
      WriteLn(i);

    for i in myObj do …