Đang chuẩn bị liên kết để tải về tài liệu:
Finding Rows in a DataView

[ Team LiB ] Recipe 3.9 Finding Rows in a DataView Problem You need to find a row or group of rows in a DataView meeting certain criteria. Solution Use a sorted DataView to find rows using columns that are not part of the primary key. The sample code contains two event handlers: Form.Load Sets up the sample by creating a DataTable containing the Orders table from the Northwind database. A DataView of the table sorted by the CustomerID and EmployeeID is created. Find Button.Click Uses the FindRows( ) method of the DataView to retrieve the array of DataRowView objects. | Team LiB Recipe 3.9 Finding Rows in a DataView Problem You need to find a row or group of rows in a DataView meeting certain criteria. Solution Use a sorted DataView to find rows using columns that are not part of the primary key. The sample code contains two event handlers Form.Load Sets up the sample by creating a DataTable containing the Orders table from the Northwind database. A DataView of the table sorted by the CustomerlD and EmployeelD is created. Find Button.Click Uses the FindRows method of the DataView to retrieve the array of DataRowView objects matching the CustomerlD and OrderlD specified. The code iterates over the collection to return the results. The C code is shown in Example 3-9. Example 3-9. File DataViewSearchPerformanceForm.cs Namespaces variables and constants using System using System.Configuration using System.Text using System.Data using System.Data.SqlClient private DataView dv . . . private void DataViewSearchPerformanceForm_Load object sender System.EventArgs e Fill the source table with schema and data. SqlDataAdapter da new SqlDataAdapter SELECT FROM Orders ConfigurationSettings.AppSettings S ql_ConnectString DataTable dt new DataTable Orders da.FillSchema dt SchemaType.Source da.Fill dt Create the data view for the Orders table and sort. dv new DataView dt dv.Sort CustomerlD EmployeelD private void findButton_Click object sender System.EventArgs e StringBuilder result new StringBuilder DataRowView foundRows Find the rows by the sort key value ProductID. try foundRows dv.FindRows new object customerldTextBox.Text employeeldTextBox.Text catch FormatException ex resultTextBox.Text ex.Message return Display the results. if foundRows.Length 0 result.Append No rows found. else result.Append ORDER tREQUIRED DATE Environment.NewLine Iterate over the collection of found rows. foreach DataRowView row in foundRows result.Append row OrderID t row RequiredDate Environment.NewLine result.Append COUNT t foundRows.Length Environment.NewLine .