|
第一章第二節(jié) Office Web Components是什么?
Office Web Components是一組的COM控件，設(shè)計(jì)的目的是為眾多的控件容器提供交互的電子表格建模，數(shù)據(jù)報(bào)表和數(shù)據(jù)可視化功能。OWC庫(kù)包含四個(gè)主要的組件：電子表格組件，圖表組件，透視表組件和數(shù)據(jù)源組件。我們將在這一節(jié)中簡(jiǎn)要論述每個(gè)控件，然后在后續(xù)各章中討論更多細(xì)節(jié)。
注釋?zhuān)?br>
COM也被稱(chēng)作ActiveX。當(dāng)微軟發(fā)明了術(shù)語(yǔ)”ActiveX”來(lái)描述COM技術(shù)時(shí)，我正在Visual Basic小組，這個(gè)術(shù)語(yǔ)使得我們絕大部分的客戶(hù)大吃一驚，因?yàn)檫@些客戶(hù)在我們停止使用術(shù)語(yǔ)”O(jiān)LE”后剛剛習(xí)慣于使用術(shù)語(yǔ)COM。我不是市場(chǎng)人員，所以本書(shū)中我只使用術(shù)語(yǔ)COM來(lái)描述組件對(duì)象模型技術(shù)。
“Office Web Components”名稱(chēng)中的單詞”O(jiān)ffice”表示這些控件就是由那些開(kāi)發(fā)微軟Excel和Access的程序員中的一部分人開(kāi)發(fā)的，并且這些控件被設(shè)計(jì)成在外觀，使用感受和行為表現(xiàn)上就像是他們的微軟Office兄弟的精簡(jiǎn)版一樣。這些控件確實(shí)不包含Excel和Access中的所有的功能——換句話(huà)說(shuō)，您也不會(huì)為了在瀏覽器中查看一個(gè)報(bào)表而動(dòng)態(tài)的下載完整的Excel和Access！然而，這些控件也確實(shí)包含了許多的常用功能，尤其是那些在與已有內(nèi)容進(jìn)行交互時(shí)所必需的功能。此外，這些控件還能夠讀寫(xiě)Excel 2000的HTML格式的文件，允許用戶(hù)點(diǎn)擊一個(gè)按鈕，將當(dāng)前的數(shù)據(jù)加載到Excel中，以便作更加強(qiáng)大的分析。本書(shū)中，我會(huì)詳細(xì)描述這些被每個(gè)組件支持和不支持的Excel和Access的顯著特性。也會(huì)向您展示如何利用自己的代碼來(lái)添加一些這些控件所缺少的功能。
OWC名稱(chēng)中的”Web”部分經(jīng)常使人誤解。這些控件是標(biāo)準(zhǔn)的COM控件，并能夠在許多的控件容器中使用，例如微軟Internet Explorer，微軟Visual Basic，微軟Visual C++，微軟Visual FoxPro和微軟Office用戶(hù)窗體。然而，這些控件的一些行為使它們尤其適合于在Internet Explorer的特殊環(huán)境中使用。例如，WEB瀏覽器為文檔提供自動(dòng)的滾動(dòng)條，但是人們經(jīng)常會(huì)為頁(yè)面中自帶一組滾動(dòng)條的控件而煩惱。電子表格控件和數(shù)據(jù)透視控件能夠通過(guò)設(shè)置，自動(dòng)調(diào)整大小來(lái)適合它們當(dāng)前的內(nèi)容，而不需要內(nèi)部滾動(dòng)條。此外，所有的控件都支持在Internet Explorer中可用的顏色名稱(chēng)，還支持?jǐn)?shù)字RGB值。這就意味著您可以使用”CornSilk”或者”P(pán)apayaWhip”(我個(gè)人的愛(ài)好)元素來(lái)設(shè)置背景顏色，控件會(huì)象Internet Explorer那樣將顏色轉(zhuǎn)換成適當(dāng)?shù)腞GB值。
OWC名稱(chēng)中的”Components”部分雖然比使用單詞”Controls”要準(zhǔn)確的多(盡管在這本書(shū)中我會(huì)為了方便將OWC稱(chēng)為”controls”)，但是也令人相當(dāng)迷惑。Office Web Components的與眾不同之處在于，他們能夠在類(lèi)似web頁(yè)面，Visual Basic窗體等等控件容器中使用，也能象不可視對(duì)象那樣在內(nèi)存中被使用。大部分的COM控件只能在控件容器中被用作可視控件，而大部分的不可視對(duì)象，例如那些通過(guò)微軟ADO接口訪(fǎng)問(wèn)的對(duì)象，只能在內(nèi)存中使用而不能放在窗體或web頁(yè)面中。OWC庫(kù)設(shè)計(jì)的目的是可以通過(guò)任何一種方式來(lái)使用。這使得您能夠通過(guò)它們暴露的用戶(hù)界面來(lái)使用這些控件或者使用這些控件的各種后臺(tái)服務(wù)，例如電子表格的重新計(jì)算功能。這種能夠以不可見(jiàn)對(duì)象的方式來(lái)使用的能力，也使您能夠在服務(wù)器上用這些庫(kù)方便地生成可以在任何web瀏覽器中查看的靜態(tài)內(nèi)容 (在這一章的后面會(huì)更多的講到這方面的內(nèi)容)。
所有控件都支持一組豐富的編程接口，這些接口能夠在微軟VBScript(Visual Basic的腳本版本)，微軟Jscript，微軟VBA(Visual Basic for Application)，Java，C++以及任何其它能夠調(diào)用雙COM接口或調(diào)度COM接口的語(yǔ)言中調(diào)用。這意味這您可以將這些組件添加到定制的解決方案中，并根據(jù)您的需要設(shè)計(jì)它們的外觀和行為。我將在后續(xù)章節(jié)中討論這些組件大部分的重要屬性，方法和事件，并在這些章節(jié)中通過(guò)講述各種解決方案來(lái)講述這些重要內(nèi)容中的絕大部分，這些解決方案可以在本書(shū)附贈(zèng)的CD中找到。
參見(jiàn)
如果您正在尋找關(guān)于COM技術(shù)的權(quán)威的指南，我建議您選讀David Chappell的《Understanding ActiveX and OLE(Microsoft Press,1996)》一書(shū)。
讓我們?yōu)g覽一下每一個(gè)組件，并討論我們能夠使用它們來(lái)建立哪些類(lèi)型的解決方案。之前已經(jīng)提到過(guò)了，后面的四章將會(huì)更加深入的討論每一個(gè)控件。
電子表格組件
電子表格組件(如圖1-1所示)象一個(gè)Excel電子表格的精簡(jiǎn)版，由一個(gè)電子表格用戶(hù)界面和一個(gè)重算引擎組成，支持Excel 2000中幾乎所有的計(jì)算功能。使用這個(gè)控件，您可以改變和重新計(jì)算數(shù)值；排序，過(guò)濾和滾動(dòng)數(shù)據(jù)；保護(hù)單元不被修改；甚至可以將數(shù)據(jù)重新裝載到Excel 2000中，以進(jìn)行進(jìn)一步的處理。電子表格控件能夠從傳入的參數(shù)中或從指向HTML格式的Excel電子表格文件的任何URL處裝入數(shù)據(jù)。
圖1—1 電子表格組件
當(dāng)您要在企業(yè)內(nèi)部互聯(lián)網(wǎng)上創(chuàng)建一個(gè)有效的電子表格模型，以便其他人能夠修改輸入值，并立刻看到重新計(jì)算的結(jié)果時(shí)，電子表格控件是很有用的。例如抵押計(jì)算器和償還進(jìn)度表模型，產(chǎn)品收支平衡模型，和銷(xiāo)售預(yù)測(cè)表。
對(duì)于任何類(lèi)型的交叉表或基于表格的數(shù)據(jù)輸入，尤其是當(dāng)您需要使用有自動(dòng)重算功能的公式時(shí)，這個(gè)控件也是很有用的。例如成本報(bào)表，事件表和預(yù)算報(bào)表。
電子表格控件能夠?qū)卧壎ǖ皆陧?yè)面上的其它對(duì)象的屬性上，然后當(dāng)數(shù)據(jù)源表明屬性值改變時(shí)自動(dòng)地更新單元以及和單元相關(guān)聯(lián)的其它單元。這使得可以在電子表格中為一些特定的環(huán)境提供實(shí)時(shí)數(shù)據(jù)，例如股票組合。
為了實(shí)現(xiàn)即使當(dāng)您在正在工作的電子表格中編輯其它的公式或者正在為其它的單元設(shè)置格式時(shí)，電子表格也能夠繼續(xù)監(jiān)視新的數(shù)據(jù)并且重新計(jì)算，電子表格控件做了專(zhuān)門(mén)的設(shè)計(jì)。
圖表組件
圖表組件(如圖1-2所示)可以說(shuō)是Excel圖表的一個(gè)精簡(jiǎn)版，它支持Excel2000中的大部分二維圖表類(lèi)型，例如Polar圖表類(lèi)型。圖表組件的另一個(gè)重要的特征是能夠立刻顯示多個(gè)圖形，從而允許您創(chuàng)建一個(gè)小型多重設(shè)計(jì)——換句話(huà)說(shuō)，根據(jù)某一屬性變化的一系列圖形可以立刻進(jìn)行比較。一個(gè)圖表可以和電子表格控件，數(shù)據(jù)透視控件或者一個(gè)ADO的Recordset對(duì)象進(jìn)行數(shù)據(jù)綁定，或者使用原始的數(shù)據(jù)來(lái)填充。當(dāng)綁定到一個(gè)數(shù)據(jù)源上時(shí)，無(wú)論何時(shí)數(shù)據(jù)源發(fā)生變化圖表控件都會(huì)更新。
參見(jiàn)
如果需要了解小型多重設(shè)計(jì)的威力的更多信息，請(qǐng)看Edward Tufte的書(shū)《Envisioning Information (Graphics Press, 1990)》。
圖1－2 圖表組件
當(dāng)需要用圖表來(lái)表示動(dòng)態(tài)的數(shù)據(jù)或監(jiān)視對(duì)你的業(yè)務(wù)而言非常重要的元素時(shí)。圖表控件會(huì)相當(dāng)?shù)挠杏�。因�(yàn)樗峁┴S富的編程模型，所以也能利用這個(gè)控件向圖表中添加許多種效果，例如在坐標(biāo)軸的最大范圍上縮放和平移，根據(jù)鼠標(biāo)的位置在應(yīng)用程序中動(dòng)態(tài)地改變圖表的內(nèi)容，或者讓用戶(hù)雙擊一個(gè)鏈接，轉(zhuǎn)到顯示所選擇的數(shù)據(jù)點(diǎn)的更多信息的新頁(yè)面。
數(shù)據(jù)透視組件
數(shù)據(jù)透視組件(如圖1-3所示)，是為了提供交互的數(shù)據(jù)報(bào)表和分析功能而設(shè)計(jì)的，它能提供Excel數(shù)據(jù)透視表的所有功能和各種外部數(shù)據(jù)類(lèi)型。它能通過(guò)OLE DB從表格，和關(guān)系數(shù)據(jù)庫(kù)中提取數(shù)據(jù)，也能通過(guò)OLE DB從OLAP服務(wù)器的cube和cube文件中為OLAP提取數(shù)據(jù)。使用這個(gè)控件，您能夠?qū)?shù)據(jù)進(jìn)行各種方式的分組，切片和排序并查看，在動(dòng)態(tài)數(shù)據(jù)上創(chuàng)建優(yōu)美的報(bào)表和交互分析功能。
雖然它最適用于數(shù)據(jù)報(bào)表和數(shù)據(jù)分析解決方案，但您可以在很多任務(wù)中使用這個(gè)控件，當(dāng)被綁定到一個(gè)OLAP cube上時(shí)，數(shù)據(jù)透視控件能夠給用戶(hù)提供一個(gè)靈活，高效的分析界面。IT機(jī)構(gòu)能夠集中精力根據(jù)他們公司對(duì)數(shù)據(jù)的理解來(lái)收集和整理數(shù)據(jù)，并將數(shù)據(jù)裝入cube中，而操作這個(gè)控件的用戶(hù)則能夠根據(jù)自己需求來(lái)對(duì)數(shù)據(jù)進(jìn)行切片。
圖1－3 數(shù)據(jù)透視表
數(shù)據(jù)透視報(bào)表也能直接在關(guān)系數(shù)據(jù)庫(kù)上完成同樣的工作，因此即使您在OLAP系統(tǒng)上沒(méi)有投資，您也能夠使用這個(gè)控件。然而，使用OLAP數(shù)據(jù)源的性能總是要快的多，原因在于這項(xiàng)技術(shù)的本質(zhì)。OLAP還有其它邏輯上的好處，我們將在第七章中探討銷(xiāo)售分析和報(bào)表解決方式時(shí)深入的討論它。
數(shù)據(jù)源組件
數(shù)據(jù)源組件(DSC)是需要從外部數(shù)據(jù)源獲得數(shù)據(jù)的控件的骨干框架。雖然這個(gè)控件是不可見(jiàn)的，但是它被廣泛的使用于從層次(OLAP中的術(shù)語(yǔ))或臨時(shí)OLAP cube中獲取和處理數(shù)據(jù)(第四章中將詳細(xì)介紹)，以及在各種各樣的控件之間建立數(shù)據(jù)關(guān)聯(lián)。既然數(shù)據(jù)源組件和那些Internet Explorer和Visual Basic中的其它數(shù)據(jù)源控件一樣，支持相同的標(biāo)準(zhǔn)接口，那么在這些環(huán)境中它就是可以互操作的。數(shù)據(jù)源組件在Access2000的數(shù)據(jù)訪(fǎng)問(wèn)頁(yè)特性中得到大量的使用，并且集成了許多Access報(bào)表引擎中的功能。
當(dāng)其它的組件要從外部數(shù)據(jù)庫(kù)獲得數(shù)據(jù)時(shí)，幾乎都要用到數(shù)據(jù)源組件。然而，它也支持它自己的一個(gè)編程模型，您能使用它來(lái)建立或者操作層次的Recordset對(duì)象。一般來(lái)說(shuō)，您不需要過(guò)多的考慮數(shù)據(jù)源控件，因?yàn)槠渌M件和Access2000數(shù)據(jù)訪(fǎng)問(wèn)頁(yè)設(shè)計(jì)器會(huì)為您設(shè)置和調(diào)用它。
疑問(wèn)：1、The "Components" part of OWC's name is a touch confusing這句如何翻譯？
2、the PivotTable component (shown in Figure 1-3) provides all the functionality found in Excel PivotTables and external data ranges.中的external data ranges如何翻譯？
附錄：英文原文
What Are the Office Web Components?
The Office Web Components are a set of Component Object Model (COM) controls designed to bring interactive spreadsheet modeling, database reporting, and data visualization to a number of control containers. The OWC library contains four principal components: Spreadsheet, Chart, PivotTable, and Data Source. We'll discuss each of these controls briefly in this section and in much more detail in the following chapters.
NOTE
--------------------------------------------------------------------------------
COM is also known as ActiveX. I was on the Visual Basic team when Microsoft invented the term "ActiveX" to describe the COM technologies, throwing most of our customers for a loop since they had just gotten used to saying COM after we stopped using the term "OLE." Since I'm not a marketing person, I'll just use the term COM in this book to describe the Component Object Model technologies. (throw…for a loop：大吃一驚)
The word "Office" in the name "Office Web Components" indicates that the controls were developed by some of the same programmers who created Microsoft Excel and Microsoft Access and that the controls were made to look, feel, and behave like small versions of their Microsoft Office siblings. These controls definitely don't have all the features found in Excel and Access—in other words, you wouldn't want to dynamically download all of Excel and Access to view a report in your browser! However, the controls do contain many of the commonly used features, especially those needed when interacting with content that's already been created. Plus, they can read and write the HTML file format of Excel 2000, allowing the user to click a button and load the current data into Excel for more powerful analysis. In this book, I'll detail the noteworthy Excel or Access features that are and aren't supported by each component. I'll also show you how to add some of these missing features with your own code.
The "Web" part of OWC's name is often misleading. The controls are standard COM controls and can be used in many control containers such as Microsoft Internet Explorer, Microsoft Visual Basic, Microsoft Visual C++, Microsoft Visual FoxPro, or Microsoft Office UserForms. However, the controls have a few behaviors that make them especially suited to the unique environment of Internet Explorer. For example, web browsers automatically support scrolling along a document, and it's often annoying for a control in the page to have its own set of scroll bars. The Spreadsheet and PivotTable controls can be set to automatically adjust themselves to fit their current content without requiring internal scroll bars. Also, all the controls support the color names available in Internet Explorer in addition to supporting numeric RGB values. That means you can set the background color of an element to "CornSilk" or "PapayaWhip" (my personal favorite), and the control will convert the color to the appropriate RGB value just as Internet Explorer would.
The "Components" part of OWC's name is a touch confusing, although it's more accurate than using the word "Controls" (though I will often refer to OWC as "controls" for convenience throughout this book). The Office Web Components are unusual in that they can be used in control containers like web pages, Visual Basic forms, and so on, as well as in memory as invisible objects. Most COM controls can be used only as visible controls in control containers, and most invisible objects, such as those accessed via the Microsoft ActiveX Data Objects (ADO) interface, can be used only in memory and cannot be put on a form or web page. The OWC library was built so that its components could be used either way, which enables you to use the controls with the user interfaces they expose or for their base services, such as spreadsheet recalculation. The ability to use the components as invisible objects also enables you to use the library on a server to easily generate static content that users can view in any web browser (more on that later in the chapter).
All the controls support a rich set of programming interfaces that you can call from Microsoft VBScript (Visual Basic Scripting Edition), Microsoft JScript, Microsoft VBA (Visual Basic for Applications), Java, C++, and any other language capable of calling a dual or dispatch COM interface. That means you can weave the components into a custom solution and make them look and act the way you want. I will discuss most of the important properties, methods, and events in the subsequent chapters and will cover many more of these in the chapters describing the various solutions found on the companion CD.
SEE ALSO
--------------------------------------------------------------------------------
If you are looking for a definitive reference on COM, I'd recommend picking up a copy of David Chappell's Understanding ActiveX and OLE (Microsoft Press, 1996).
Let's take a brief look at each of the components and discuss what kinds of solutions you can build with them. As already mentioned, the next four chapters will cover each component in more depth.
The Spreadsheet Component
The Spreadsheet component (shown in Figure 1-1) is like a small version of an Excel spreadsheet, complete with a spreadsheet user interface and a recalculation engine that supports nearly all the calculation functions in Excel 2000. With this control, you can change or recalculate values; sort, filter, and scroll data; protect cells; and even reload the data into Excel 2000 for further manipulation. The Spreadsheet control can load its data from an embedded parameter or from any URL that points to an Excel spreadsheet saved in HTML file format.
Figure 1-1. The Spreadsheet component.
The Spreadsheet control is useful anytime you want to make a spreadsheet model available on your intranet so that others can change the input and instantly view the recalculated results. Examples include a mortgage calculator and payment schedule model, a product break-even model, and a sales forecasting model.
This control is also useful for any kind of cross-tabulated or grid-based data entry, especially when you need to use formulas with automatic recalculation. Examples include expense reports, timesheets, and budgets.
The Spreadsheet control has the ability to bind cells to properties of other objects on the page and then automatically update the cell and its dependents when the source indicates that the property value has changed. This makes it possible to feed real-time data into the spreadsheet for scenarios such as a stock portfolio.
The Spreadsheet control is specifically designed to keep listening for new values and recalculating even when you are editing other formulas or formatting other cells in the spreadsheet you're working on.
The Chart Component
The Chart component (shown in Figure 1-2) is comparable to a small version of Excel charting, supporting most of the two-dimensional chart types in Excel 2000 as well as a Polar chart type. Another big feature is that the Chart control can display many plots at once, allowing you to create a small-multiple design—in other words, a collection of plots that vary by one property and can be compared at a glance. A chart can be data-bound to the Spreadsheet control, the PivotTable control, or an ADO Recordset object, or it can be filled with literal data values. When bound to a data source, a Chart control will update whenever the source data changes.
SEE ALSO
--------------------------------------------------------------------------------
For more information on the power of small-multiple designs, see Edward Tufte's book Envisioning Information (Graphics Press, 1990).
Figure 1-2. The Chart component.
The Chart control is primarily useful any time you need to chart live data or monitor a specific metric critical to your business. Because it supports a rich programming model, you can also add many effects to a chart with this control, such as zooming and panning on large axes, dynamically changing other content in the application based on the mouse's location, or letting users double-click to link to a new page displaying more information about the selected data point.
The PivotTable Component
Designed to deliver interactive data reporting and analysis, the PivotTable component (shown in Figure 1-3) provides all the functionality found in Excel PivotTables and external data ranges. It can retrieve data from tabular, relational databases through OLE DB, as well as from OLAP server cubes and cube files through OLE DB for OLAP. Using this control, you can view data grouped, sliced, and sorted in a variety of ways, creating polished reports and interactive analysis on live data.
You can use this control for many tasks, although it's best suited for database reporting and data analysis solutions. When bound to an OLAP cube, the PivotTable control can provide the user with a flexible, high-performing analysis surface. IT groups can concentrate on collecting and cleaning data and loading it into cubes that reflect the way their company thinks about the data, while users working with this control can create slices of the data to fit their own needs.
Figure 1-3. The PivotTable component.
The PivotTable control can also perform the same operations directly on a relational database, so you can use it even if you don't have an investment in an OLAP system. However, the performance when using an OLAP data source is always much faster because of the nature of the technology. OLAP has other logical benefits that we'll discuss further when we explore the Sales Analysis and Reporting solution in Chapter 7.
The Data Source Component
The Data Source component (DSC) is the backbone for controls that require data from external sources. Although this control is invisible, it is widely used to retrieve data, manipulate data into hierarchies or temporary OLAP cubes (more on this in Chapter 4), and establish data bindings between the various controls. Since the DSC supports the same standard interfaces as other data source controls found in Internet Explorer and Visual Basic, it will interoperate in those environments. The DSC is used heavily in Access 2000's data access pages feature and encapsulates much of the functionality found in the Access reporting engine.
The DSC is involved almost any time the other components retrieve data from an external database. However, it also supports a programming model of its own, and you can use it to build or manipulate hierarchical Recordset objects. In general, you don't need to think much about the DSC since the other components and the Access 2000 Data Access Page Designer will set it up and implement it for you.
|
