Tài liệu Performing Advanced Filtering pdf

Performing Advanced Filtering The RowFilter property of a DataView is similar to a WHERE clause in a SELECT statement. You can therefore use very powerful filter expressions in your DataView. For example, you can use AND, OR, NOT, IN, LIKE, comparison operators, arithmetic operators, wildcard characters (* and %), and aggregate functions. N ote For full details on how to use such filter expressions in your DataView objects, refer to the DataColumn .Expression property in the .NET online documentation. Here's a simple example that uses the LIKE operator and the percent (%) wildcard character to filter rows with a CustomerName that starts with Fr: string filterExpression = "CompanyName LIKE 'Fr%'"; customersDV.RowFilter = filterExpression; Notice that the string Fr% is placed in single quotes-which you must do for all string literals. When this code replaces the existing code in the UsingDataView.cs program shown earlier in Listing 13.1 , the output is as follows: FRANK Frankenversand Germany FRANR France restauration France FRANS Franchi S.p.A. Italy N ote I've made this change in the UsingDataView2.cs program (the listing is omitted from this book for brevity). Feel free to examine and run this program. . Performing Advanced Filtering The RowFilter property of a DataView is similar to a WHERE