tailieunhanh - Modifying Data Using a Strongly Typed DataSet

Modifying Data Using a Strongly Typed DataSet In Chapter 10, you saw how to create and use a strongly typed DataSet class named MyDataSet. You can use objects of this class to represent the Customers table and rows from that table | Modifying Data Using a Strongly Typed DataSet In Chapter 10 you saw how to create and use a strongly typed DataSet class named MyDataSet. You can use objects of this class to represent the Customers table and rows from that table. In this section you ll see how to modify data using a strongly typed object of the MyDataSet class. Note One of the features of a strongly typed DataSet object allows you to read a column value using a property with the same name as the column. For example to read the CustomerlD of a column you can use rather than myDataRow CustomerID . See Chapter 10 for more details on reading column values. The following methods in the MyDataSet class allow you to modify the rows stored in a MyDataSet object NewCustomersRow AddCustomersRow and RemoveCustomersRow . You can find a row using the FindByCustomerID method. You can check if a column value contains a null value using methods such as IsContactNameNull and you can set a column to null using methods such as SetContactNameNull . You ll see these methods used shortly. Note You ll find a completed VS .NET example project for this section in the StronglyTypedDataSet2 directory. You can open this project in VS .NET by selecting File Open Project and opening the file. You ll need to change the ConnectionString property of the sqlConnection1 object to connect to your Northwind database. The Form1_Load method of the form in the example project shows how to add modify and remove a row to a strongly typed DataSet object named myDataSetl. You can see the steps that accomplish these tasks in the following Form1_Load method private void Form1_Load object sender e populate the DataSet with the CustomerlD CompanyName and Address columns from the Customers table myDataSet1 Customers get the Customers DataTable myDataTable II create a new DataRow in .