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 Dat

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

Note 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

Note 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