Data Source Control Parameter class Parameter

ParameterClass indicates parameters used by the ASP. NET data source control to select, filter, or modify parameterized SQL queries, filter expressions, or business object method calls.ParameterThe object is included in the parametercollection object. Computing at runtimeParameterObject, bind the value of the variable it represents to any method used by the data source control to interact with the data.

Use the parameter classes provided by ASP. NET (including controlparameter, cookieparameter, sessionparameter, profileparameter, and querystringparameter) with the data source control and data binding control to generate Web-based data applicationsProgram. Data source controls use these classes to bind specific types of values contained in web applications to placeholders in SQL query strings and Business Object method parameters. For example,ControlparameterClass is used to bind all public properties of Web server controls;SessionparameterClass is used to bind user session values;QuerystringparameterAndCookieparameterClass is used to bind the value to the httprequest class. If you want to implement your own custom parameter types, extendParameterClass.

ParameterObjects are very simple: they have the name and type attributes and can be declared and tracked between multiple HTTP requests. When a parameter is bound to a value, all parameters support the defaultvalue attribute, but the value is calculated as a null reference (nothing in Visual Basic) at runtime ). SetParameterWhen the collection of objects is used for data source controls, their order in the collection may be very important.

related materials: data source controls, Part 1: parameters
Scott Mitchell's ASP. NET 2.0 data tutorial 5: Declaration parameters
Create your own parameter to the data-source control's Parameters collection