ASP.NET Lecture 6
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This document provides an overview of custom server controls in ASP.NET 4.0. It discusses why to use custom server controls, how to create a completely custom control by inheriting from the Control class and overriding methods like Render(), and how to add custom controls to a website and reference their assemblies. It also covers styling custom controls, view state, postback data, and adding child controls.
![REFERENCES
[1] Beginning ASP.NET 4 In C# 2010, Matthew
Macdonald, Apress
[2] Web Application Architecture Principles,
Protocols And Practices, Leon Shklar And Richard
Rosen, Wiley
[3] Professional AS P.NE T 4 In C# And VB, Bill
Evjen, Scott Hanselman And Devin Rader, Wiley
[4] Pro ASP.NET In C# 2010, Fourth
Edition,matthew Macdonald, Adam Freeman, And
Mario Szpuszta, Apress](https://image.slidesharecdn.com/asp-net-lect6-130212120434-phpapp02/85/ASP-NET-Lecture-6-28-320.jpg)
ASP.NET Lecture 6
- 1. ASP.NET 4.0 Julie Iskander MSC. Communication and Electronics
- 2. Lecture Outlines Custom Server Controls
- 3. Custom Server Controls Why use them? ◦ Complete control over rendered HTML ◦ Better design-time support More difficult then User Controls
- 4. Custom Server Control Inherits System.Web.UI.Control ◦ Provides common properties and methods ◦ Ex. ID, ViewState, Controls Sometimes inherits from System.Web.UI.WebControls.WebContr ol ◦ Adds more features to implement styles ◦ Ex. Font, ForeColor , BackColor
- 5. Creating a Completely Custom Control Steps: 1. Create a new ASP.NET Server Control Project 1. Add a new class derive from Control 2. Override Render() method Use HTTPTextWriter to write the wanted HTML. 2. In your website: 1. Add reference to the custom control assembly (.dll) 2. Register assembly (.dll) in page 3. Register assembly (.dll) in web.config 4. Add the item to the Toolbox 5. Use in page
- 6. Step 1
- 8. Convert from an HTML to an aspx page
- 10. Styling custom Controls Better inherit WebControl Don’t overrride Render() Specify base tag of your control in constructor Add public properties Initialize Properties by overriding OnInit() Override AddAttributeToRender() to add the wanted attribute values Override RenderContent() to add the wanted content
- 12. Convert from an HTML to an aspx page
- 13. View State To save and retrieve property values in the view state To store information of the control between postbacks.
- 15. Convert from an HTML to an aspx page
- 16. Postback Data and Change Event To process the data that’s posted to the page. Implement IPostBackDataHandler ◦ LoadPostData() called on page postback before any control event handling, to update control state ◦ RaisePostDataChangedEvent() to fire events ◦ The control must have a name attribute for postback to work
- 20. Convert from an HTML to an aspx page
- 21. Triggering a PostBack Is supported by a JavaScript function named __doPostBack(); Override AddAttributesToRender() Add a javascript event attribute to the tag The value is set using Page.ClientScript.GetPostBackEventReference ()
- 23. Convert from an HTML to an aspx page
- 24. Controls Property A collection of childern controls to be added to the control rendered with RenderChild()
- 25. Convert from an HTML to an aspx page
- 26. Lab #6 Create a custom control ◦ A labeled textbox with onTextChange event of the textbox and a Text attribute for the label. The data must be retained between postbacks. ◦ Use it in register.aspx
- 27. Report #6 What is control state of a control?
- 28. REFERENCES [1] Beginning ASP.NET 4 In C# 2010, Matthew Macdonald, Apress [2] Web Application Architecture Principles, Protocols And Practices, Leon Shklar And Richard Rosen, Wiley [3] Professional AS P.NE T 4 In C# And VB, Bill Evjen, Scott Hanselman And Devin Rader, Wiley [4] Pro ASP.NET In C# 2010, Fourth Edition,matthew Macdonald, Adam Freeman, And Mario Szpuszta, Apress
Editor's Notes
- #7: Create a new project ASP.NET Server Control HTMLTextWriter class to write raw HTML, provides methods to manage style attributes and tags
- #9: SimpleControl
- #10: RenderControl is not overriden
- #13: ControlWithPropertyControlWithExceptionHandlin
- #16: ControlWithViewState
- #17: LoadPostData tell ASP.NET whether a change happened and an event is required.
- #19: For a custom textbox
- #21: ControlWithPostBack
- #24: ControlWithPostBack
- #26: GreetControl