Demonstrates a search form that filters the database results. The user can filter either by company name or by id. The company name can be searched with wildcard matching by using the '%' symbol. On select the search criteria entered in the textboxes is automatically extracted by the SelectParameters collection and passed to the select command. The SmartDataSource.MonitorParameters property is enabled. In this way SmartDataSource automatically triggers data rebinding if some of the search criteria changes.

The SmartDBView.OnEmptyData property determines the behavior when the search results are empty. In this example it is set to EmptyDataTemplate, which means that the EmptyDataTemplate template property is rendered in the case of empty dataset. The page style is set to DropDown.

To quickly create a search form do the following:

1. Open the SmartDataSource configuration dialog.
2. Add parameters to the SelectParameters or FilterParameters collection. Set the Type of the parameters - String, Decimal, Boolean, etc.To change the type click the "Show advanced properties" in order to show the property grid of the parameters.
3. Edit the Select command or the FilterExpression in order to use the new parameters.
4. From the SmartDataSource smart-tag panel select either "Create Select Search Panel" or "Create Filter Search Panel". This will create new user interface controls and configure the parameters to extract their values from the new controls.
5. If you are expecting NULL values for the parameters set the property CancelSelectOnNullParameter of SmartDataSource to False.

The user could specify no search criteria. In this case the parameter values will be NULL. If you want the parameter to be ignored when it is NULL you can use the following construct in the WHERE clause of the SELECT statement:

WHERE (CompanyName LIKE @CompanyName OR  @CompanyName IS NULL).

In this way the @CompanyName parameter will filter the values when it is not NULL, but if it is NULL all data rows will be returned. In order this to work make sure that the CancelSelectOnNullParameter property of SmartDataSource is set to False.

CREATE TABLE [dbo].[Shippers] (
	[ShipperID] [int] IDENTITY (1, 1) NOT NULL ,
	[CompanyName] [nvarchar] (40) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
	[Phone] [nvarchar] (24) COLLATE SQL_Latin1_General_CP1_CI_AS NULL 
) ON [PRIMARY]
GO