Giải thích làm thế nào một cửa hàng dữ liệu DataTable Thêm dữ liệu mới hàng đến một Kiểm tra bảng, cập nhật, và loại bỏ các giá trị hiện tại trong một hàng của bảng Giải thích làm thế nào phân biệt giữa chờ và dữ liệu cuối cùng giá trị mã Tích hợp xác minh dữ liệu vào đối tượng DataTable của bạn | Chapter 3 Storing Data in Memory After completing this chapter you will be able to Explain how a DataTable stores data Add new data rows to a table Examine update and remove existing values in a table row Explain how differentiates between pending and final data values Integrate data verification code into your DataTable object Adding columns to a DataTable is an essential step in managing data in but the columns themselves contain no data. To store actual data values in an table you must use the DataRow class. After you place one or more data rows in a table the real work of managing application-specific information begins. This chapter introduces the DataRow class and its role in data storage within each data table. Note The exercises in this chapter all use the same sample project a simple editor of DataRow records within a single DataTable. Although you will be able to run the application after each exercise the expected results for the full application might not appear until you complete all exercises in the chapter. Adding Data Adding new data rows to a table is a three-step process 1. Create a new row object. 2. Store the actual data values in the row object. 3. Add the row object to the table. Creating New Rows The DataColumn objects you add to a DataTable let you define an unlimited number of column combinations. One table might manage information on individuals with textual name fields and dates for birthdays and driver-license expirations. Another table might exist to track the score in a baseball game and contain no names or dates at all. The type of information you store in a table depends on the columns included in that table along with the name data type and field constraints for each column. 37 38 Microsoft 4 Step by Step The DataRow class lets you store a single row of data in a table. However a row of data that tracks customers or medical patients is not the same as a row that tracks baseball scores. The columns .
