Comparing Values

王朝asp·作者佚名  2006-01-10
窄屏简体版  字體: |||超大  

Comparing Values

It's sometimes useful to be able to validate one control's data by comparing

it to the data in another control or to a specified value. The

CompareValidator control allows you to do both. An example familiar to all

Web users would be the need to compare two entries of a user's password. In

order to confirm that a user has entered the correct password, most sites

require the user to enter the same value twice. Figure 8.4 shows a sample

page comparing two text box controls' values.

Figure 8.4. The CompareValidator control allows you to compare the values

in two controls.

Follow these steps to add the Password Change form to your project:

Select Project, Add Existing Item. Be sure to change the Files of Type

combo box to "All Files (*.*)".

Select all PwdChange.* files from the Jumpstart\ValidationControls folder.

There should be three files: PwdChange.aspx, PwdChange.aspx.resx, and

PwdChange.aspx.vb.

Bring up the PwdChange.aspx file in design mode.

Click immediately to the right of the Confirm Password text box to place

the insertion point after the control.

In the Toolbox window, double-click the CompareValidator control to place a

new instance of the control to the right of the Confirm Password text box.

Set the properties of the new control as shown in Table 8.7.

Table 8.7. Set These Properties in the CompareValidator Control Property

Value

ControlToCompare txtPassword

ControlToValidate txtConfirm

ErrorMessage 'Password' and 'Confirm Password' must match

Run the application, bring up the Password Change page, and attempt to

change the password. Check out what happens when you enter two different

passwords on the page梱ou should see the error message displayed in the

CompareValidator control.

OTHER USES FOR THE COMPAREVALIDATOR CONTROL

The CompareValidator control does more than just compare the values of two

controls. You can also compare a control to a specific value. In addition,

the Operator property of the control allows you to check for other

comparisons besides equality. The Operator property can be any of these

values: Equal (the default value), NotEqual, GreaterThan, GreaterThanEqual,

LessThan, LessThanEqual, or DataTypeCheck. This last option, DataTypeCheck,

allows you to simply check that the value entered into the control matches

a specific data type. If you select DataTypeCheck for the Operator property

and set the Type property to Date, for example, and leave ControlToCompare

and ValueToCompare empty, you can allow the user to enter any date, but

only a date.

 
 
 
免责声明:本文为网络用户发布,其观点仅代表作者个人观点,与本站无关,本站仅提供信息存储服务。文中陈述内容未经本站证实,其真实性、完整性、及时性本站不作任何保证或承诺,请读者仅作参考,并请自行核实相关内容。
 
 
© 2005- 王朝網路 版權所有 導航