Working on User Interface Controls
The user interface controls in the .Net platform are easy to use, if you are using and IDE like Visual Studio .Net. All you have to do is to just drag and drop the controls in the design view to the web page or the form.
If you double click the web page (.aspx) you will be taken to the code page where you can add the code needed to handle the controls that you have added to the page. In ASP.Net you have the controls grouped in different categories like html server controls, web server controls, and validation controls in the tool palette.
You can click the tab that you want and simply drag the controls the page and drop them there. With the user of the property windows you can set the properties of the controls in design time. You can also set the properties during runtime through the code.
If you are planning to use a set of controls consistently in your project then you can group these controls to form a user controls so that you are creating a single user control that has all the other controls.
User controls are created in .ascx file and are compiled to DLLs. You have to add this to the toolbox so that you can add them to your page whenever needed just like the other controls in the tool palette. You can also create custom controls with complex properties and functionalities.