The "ASP. NET" validation control

Learn about the following six validation controls by looking at ASP. Do you know what each control does without Chinese comments? Down here.

Introduction some of these controls.

First, RequiredFieldValidator (Limit empty fields)

Used to make a specific input control a required item, and if empty, a hint is given.

Common Properties:

ControlToValidate: The control to validate

ErrorMessage: Information for the prompt.

Display: static and Dynamic Dynamics

Static statics:

Dynamic Dynamics

Second, CompareValidator (compare controls)

Used to compare the value entered by the user into the input control with the value or constant value entered into the other input control

More.

Common properties In addition to the above control property settings are:

Operator: Gets or sets the comparison operation to perform.

ValueToCompare: Gets or sets a constant value to be entered with the input controlled by the user into the validated in pieces the value to compare.

if it's a date type, put operator change it and you can change it to a date.

Third, RangeValidator (check the specified range)

Check that the value of the input control is within the specified range of the setting, take the date type as an example, exceed the prompt, and set the properties as follows:

Iv. RegularExpressionValidator (using an expression to check values)

The function of this control is to let us write according to certain rules, only need to select the corresponding expression in the ValidationExpression attribute list.

v. CustomValidator (custom validation)

To perform user-defined validation of the input control, you need to write the method for server-side validation, which is the following:

There are two parameters, the first one is the control that represents the validation, and the second represents the event data. The second parameter has two Properties: The IsValid is used to indicate that a validated control

is validated, the Value property represents the values.

<span style= "FONT-SIZE:18PX;" >   protected Voidcustomvalidator1_servervalidate (object source, ServerValidateEventArgs args)        {            String userName = args. Value;            SqlConnection con =db.createconnection ();            Con. Open ();            SqlCommand cmd = Newsqlcommand ("Select Count (*) from login whereusername= '" +username+ "'", con);            int Count =convert.toint32 (cmd). ExecuteScalar ());            if (Count > 0)            {                args. IsValid = false;            }            else            {                args. IsValid = true;            }            Con. Close ();        } </span>

Vi. ValidationSummary (verification rollup)

The error message that is displayed in the control is specified by the ErrorMessage property of each validation control. If the validation control is not set

ErrorMessage property, the error message is not displayed for that validation control.

Vii. Summary

The above summary of the control is learned in the video, comparative basis, the current understanding of it is this Some, feel more impressed by summing up

some. Many of the original verification is through the code to complete, after learning to find a control to solve, very cool.

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The "ASP. NET" validation control