vcl | 易学教程

Steema Software将携TeeChart VCL年度版参加“ITDevCon 2013”

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11月14、15日，“ITDevCon 2013”将在意大利城市维罗那举行，西班牙厂商Steema Software将带着旗下著名图表控件 TeeChart VCL 参加。Steema Software表示，他们很高兴参加“ITDevCon 2013”，他们会带着TeeChart VCL第五个年度版亮相会议与欧洲各国Delphi开发者进行交流。为期两天的ITDevCon，主要关注最新Delphi技术，与会者可以选择自己感兴趣的话题，安排行程，学习如何用一种语言、一种框架在多元设备、本地应用程序中发挥RAD IDE Delphi的最大功能。来源： oschina 链接： https://my.oschina.net/u/1254919/blog/171028

使用跨平台图表控件TeeChart如何从DAT或TEXT文件中导入数据

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大多数开发人员在使用TeeChart进行开发的时候，都需要访问包含在文本文档中的一些数据，本次教程将详细讲解如何去实现这一步骤。文本文件通常包含使用空格键或者是TAB键分隔开的数字和文字： TeeChart官方最新版免费下载地址比如下面的文本，包含两个字段，使用空格作为字段分隔： 0.1 24 0.5 143 0.2 321 0.1 100 从一个文本文件读取数据(如果列分隔符是正确的)，开发者可以使用TSeriesTextSource组件，可以根据自身的数据设置ileName、Fields和FieldSeparator属性。然后只需通过设置TSeriesTextSource.Series或Series.DataSource属性将系列文本源组件连接到一个图表系列。 1 创建一个新的应用程序。 (File->New->Application) 2 从"Additional"面板选项卡中拖放TChart组件。 3 双击Chart1组件显示TeeChart编辑对话框。(或右键单击Chart1并单击"Edit...") 4 单击"Add..." 按钮,选择"Line"系列风格,单击OK按钮。(或双击"Line"图表) 5 关闭编辑器对话框(或按Esc键关闭它)。 6 找到“TeeChart”组件面板选项卡并拖放SeriesTextSource组件。 7

Visual bug in Windows title bar with VCL Styles enabled application and display scaling

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问题 Currently I am testing various aspects of VCL styles enabled applications. I noticed, that with Windows scaling higher than the default 96 dpi/100%, the icon and the title bar text of the VCL Form are too big in size - and both are to close together -, please see attached screenshots. This is especially true with higher scalings like 200% or 250% (e.g. used on 4K displays and Windows 10), but even with a scaling of 144 dpi/150%, the problem is already visible. This is true for all styles

Allow multiple MDI Parent Forms on same Application

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问题 I'm trying follow what was suggested in this answer, changing this part of Vcl.Forms.pas : procedure TCustomForm.CreateWindowHandle(const Params: TCreateParams); var CreateStruct: TMDICreateStruct; NewParams: TCreateParams; begin if (FormStyle = fsMDIChild) and not (csDesigning in ComponentState) then begin {if (Application.MainForm = nil) or (Application.MainForm.ClientHandle = 0) then raise EInvalidOperation.Create(SNoMDIForm);} with CreateStruct do begin szClass := Params.WinClassName;

Ctrl+Backspace in Delphi Controls

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问题 the Ctrl+Backspace keyboard shortcut normally deletes the word to the left from the caret. But it does not work in any of the standard Delphi controls you would expect ( TEdit , TMemo , TComboBox ect.). Interestingly, Ctrl+Delete works just fine. Does anybody know how to correct this behaviour easily? I know that overriding the KeyDown procedure would do it, but this is a rather too complicated as KeyDown has to be overridden for every component. 回答1: This is not a Delphi-specific issue.

VCL events with anonymous methods - what do you think about this implementation?

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问题 Since anonymous methods appeared in Delphi I wanted to use them in VCL components events. Obviously for backward compatibility the VCL wasn't updated, so I managed to make a simple implementation with a few caveats. type TNotifyEventDispatcher = class(TComponent) protected FClosure: TProc<TObject>; procedure OnNotifyEvent(Sender: TObject); public class function Create(Owner: TComponent; Closure: TProc<TObject>): TNotifyEvent; overload; function Attach(Closure: TProc<TObject>): TNotifyEvent;

Custom drawing of TCustomListbox items

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问题 I'm rewriting a VCL component showing a customized TCustomListbox to Firemonkey in Delphi 10.2. The customization used an overridden DrawItem , basically adding some indentation and setting the text color depending on the item text and index. DrawItem made it rather easy, but there seem to be nothing like that in FMX. I can override PaintChildren and draw every item myself, but then it looks differently and I have to deal with scrolling and everything myself. I'm just starting with FMX and

What is the best method for implementing mouse wheel activity in Delphi VCL forms?

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问题 As a long time user of Delphi 7, I've rolled my own mouse wheel handling in a few controls but lately I've noticed that some recent applications only need the mouse cursor to be placed over a control (e.g. a list box or tree view) for the mouse wheel activity to cause that control to scroll. This feels nice (as opposed to having to click focus a control before it responds to the wheel). Now I've moved to Delphi 2010 I'm wondering what is the 'correct' behavior? And what can I use in Delphi

Wrong auto-scaling controls with anchors on PageControl in VCL form

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问题 I have problems with auto-scaling of controls on my form for different monitor DPI settings. Rad Studio 10.2 Tokio. "Enable high-dpi" is on. I set the form's PixelsPerInch to 96 at design time. I put TPageControl on a form, create a TTabSheet page in it, put some controls on a page and set their Anchor property to akRight (in addition to akLeft and akTop). When the program is run on a monitor with a resolution of 120 DPI right edge of those controls appear extended beyond the right boundary

Controls on top, like TPanel can do?

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问题 My program is doing a time consuming task, and I would like to display a TImage in the middle of the application window, but it will not stay on top - my VST is always on top. However, when I use a TPanel, it stays on top? How can I make my TImage do that? In fact, a solution that applies to all controls would be splendid :) Thanks! 回答1: You need a windowed control (that is, a control with a window handle, or a "proper" control) to display your message, because a non-windowed control cannot