All of the data validation controls are displayed in the toolbox when ASP.
NET displays a Web form or Web user control in design view in Visual Studio . You can also (directly in HTML or programmatically) add data validation controls to Web forms and Web user controls. NET data validation control is the Required Field Validator control.
The Required Field Validator linked to it has an ID attribute called rfv Name and I've included some of the most commonly used attributes.
I used the Control To Validate attribute to link Required Field Validator to the textbox.
Furthermore, the data validation scripts are protected inside the Web server so they are not vulnerable to malicious user modifications.
In its efforts to improve Web development on the whole, Microsoft included in ASP. NET validation controls), which offer an exceptional solution to data validation. NET comes with five validation controls as well as a summary control. NET Web application renders the data validation controls on the user's computer as HTML elements based upon the selected Target Schema property.
More precisely, the rendered HTML uses a script library called Web and implements Microsoft JScript functionality that is only supported by Microsoft Internet Explorer 4.0 and later versions.
The data validation controls are shown in Figure 1 as they appear in the Visual Studio . To use it, you link the Required Field Validator control to another control, such as a textbox, and use it to determine if the linked control has a value entered into it or it is empty.
If the linked control has a value entered into it, data validation will succeed.
This increases performance and reduces traffic over the Web.
A slightly negative aspect of validating data on the user's computer is that the validation is performed via a script residing in the Web page. You only have two possible scripting languages that you can use on a user's computer: VBScript or Java Script.