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Rowupdating command argument

Historically, Microsoft has provided support for accessing data in a variety of relational and nonrelational data stores by shipping APIs that existing VB developers have become quite familiar with over the years including VBSQL, ODBC, DAO, RDO, OLE DB, and ADO.

Although this continued evolution meant that VB developers had to learn new techniques along the way, the benefits of learning the models meant a unified relational data access model (ODBC), increased simplicity (DAO), increased performance (RDO), and increased reach to nonrelational sources (ADO).

To that list you can now add the data access classes of the Services Framework. NET, serve to implement a managed interface to OLE DB and SQL Server, increase performance when using SQL Server, and allow data to be manipulated in a fashion commensurate with distributed application development utilizing the Internet and XML.

Even though learning a new data access model may at first be daunting, it will also help you build modern, distributed applications.

NET來自動生成。當完成資料的綁定,HTML 碼上其實就幫我們寫好了和資料庫繫結的要項了。如圖,紅色的框線是與資料庫連結的資料,底下有Delete Command、Insert Comman、Select Command、Update Command,後面接寫的是資料庫使用的陳述式。 在browser端,當Grid View的某個按鈕按下去的時候,要怎麼讓系統知道現在按的是要呼叫資料庫的Delete 陳述式還是Update陳述式呢?這就要使用Button的Command Name和Command Argument屬性了,如果有興趣請看 活用Button 控制項:Command Name、Command Argument屬性介紹 但判別哪個Command Name用哪個Command Argument 的判斷程式要寫在哪?我想「應該」就是寫在Row Command事件的處理常式底下。 上面只是個臆測,從使用Button控制項得來的經驗來推測,但是只能說是猜測,因為我們在ADO. NET底下的Row Command事件下也沒有自已生成像 if Command Name = “Update” then Command Argumet 的常式。不過也不是子虛烏有,在MSDN裡的Grid View.

NET 的設計去做資料列刪除的動作,為了讓範例在部落格上存活,我就在Row Deleting 裡取消刪除。大家實作時可以把這段刪掉試試看動用Command Name 的內建字的下場是什麼。而Button1的Command Name「Add」其實也是保留字,但它是作用在Details View身上的,所以這邊拿來用是沒關係的。 例如:Grid View整個刪除的流程是: 按一下Grid View的刪除按鈕 → (Grid View的Row Deleting 事件) → 刪除資料列 → (Grid View的Row Deleted事件)。 前一篇文章 Grid View中和「刪除」事件有關的事件常式 已經交待了在 Row Deleting 事件與Row Deleted事件中,利用二個重要的參數來撰寫常式。 這篇文章的重點就放在 按Grid View的刪除按鈕→刪除資料列,控制項和資料庫是如何完成聯繫並達成工作的。 我們在頁面上加入Grid View控制項,並繫結資料,整個都是交給ADO.

As a result, classic ADO provides a flat view of data that is not strongly typed. NET is built from the ground up for distributed applications used in today's disconnected scenarios. Using XML alleviates several of the burdens of classic ADO.

Because the classic ADO model was developed primarily with continuously connected access in mind, creating distributed applications with it is somewhat limiting.Far and away the single most important technique for corporate VB developers is data access.Most of the applications written in today's corporate environments involve displaying and manipulating operational data and line of business data.Typically clauses are used inside stored procedures or inline SQL to retrieve data from multiple tables.However, this does not allow you to assemble data from multiple data sources and easily determine from where the data comes. NET applications to cache data and pass it between tiers in a distributed application thereby alleviating the need to rely on proprietary schemes or COM marshalling.After you have run the website, you will see the Grid View showing details of employees in tabular format.We have selected four columns from Employee Details table. NET 在 Command Name 的內建字「Delete」,所以當按下按鈕時,網頁會邊進行我們給的Row Command事件處理常式,一邊引發Row Deleting事件按照 . Text。 ◎ 行18 Dim remove_item As New List Item(),定義為List Item而不用List Box當繼承的容器,這樣的話,不只是List Box適用這個方式,像Drop Down List、Check Box List都可以用。 ◎行38-43,這是重點,因為我們在設計「移除」功能時用了 .In addition, the classic ADO model doesn't handle hierarchical data particularly well.Although it is possible to create hierarchical recordsets using the Microsoft data shape provider, it is not simple and is therefore not often used.


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