I have an asp:textbox. On textchange of this textbox, I'm doing validation for the text entered. If the text entered is incorrect, I want to flash a message of incorrect text entered. Please re-enter. How can I do this in ASP?
Just use a RegularExpressionValidator and keep client validation property at it's default "true" value. The control will handle this behavior for you.
Here's an example in action with the code: http://www.w3schools.com/ASPNET/showasp.asp?filename=demo_regularexpvalidator
You should avoid using that property if you can. Your validation code will only run when you postback to the server, and you don't want to do a full postback every time the text changes unless you really have to. Instead, use javascript to handle the onchange event of the input element rendered in the raw html by asp.net. Then remember to duplicate your validation code on the server.
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I have a RegularExpressionValidator for a TextBox in a control, which itself is part of another control. When I click the button to submit the form, it seems that it should not do so unless all child controls are properly validated. However, what ends up happening is that I see the validation error message pop up for each control that failed to validate before the page posts back anyway and fails when it can't parse the malformed input.
I have tried surrounding the failing code with if (Page.IsValid) {...} to make sure it doesn't run without complete validation, but the property ends up being true by the time I hit the breakpoint.
Shouldn't an entire page be invalid if any child controls are not successfully validated?
Do you have different ValidationGroup controls defined? As long as the validators in the same validation group as the button are all setup correctly, yes it should block. Unless, for some reason, the JS is failing to load for the validators.
HTH.
Set "CausesValidation = true " to your submit button, I guess your problem will be solved.
Have you called Page.Validate() before using Page.IsValid ?
I notice with ASP.NET if the server side control TextBox is used with out autopostback it will not submit (or postback) the form when typed text ends with enter, which is different from the behavior for plain old HTML pages. Fine, I can set autopostback to get the behavior I want after the enter key. However, autopostback will also cause submit (or postback) when the typed text does not end with enter but focus has changed (i.e. with tab or mouse click), which again is different from plain old HTML pages.
How can I get an ASP.NET page to behave the same as a plain old HTML page with respect to text input regardless of whether enter key or change of focus occurs?
There is some additional setup work, check out this article: http://geekswithblogs.net/ranganh/archive/2006/04/12/74951.aspx
There is a HtmlInputText class: http://msdn.microsoft.com/en-us/library/f8kdafb5(v=VS.71).aspx
The behavior you are describing isn't asp.net specific. It's whether you are capturing the enter key in JavaScript and submitting the form. I think the key code for the enter key is 13.
After reading your question again. I'm not sure what you mean when you say "plain old Html page." What behavior are you expecting? ASP.Net output is html.
I have an ASP.NET page where I am dynamically building LinkButton and TextBox elements. These elements are being built during the OnInit event of the page. The user can then perform an action that changes the values of these elements. The values of these elements are changed via JavaScript. When the user clicks a button, a server-side event is fired. This event parses the value in each control. I have noticed that the value for the TextBox is correct, but the value for the LinkButton is not.
Can only certain types of controls in ASP.NET be dynamically generated and have their values retrieved on the server side?
Thank you.
You can't get value of link button at server side. You can only get form elements' values at server side.
If you want to pass more values to server side, you can use hidden input elements.
No, generally you can create whatever element you like, given you create it inside the OnInit event or if you add the INamingContainer (marker) interface, you should override the CreateChildControls() method and create your elements in there.
But what do you mean by changing the value of the LinkButton via JavaScript? What exactly do you change on the LinkButton?? Could you provide more details?
Ensure that the "runat=server" property is set for each form element you want to retrieve via server code, and that you have an ID associated with each.
The textbox is working because value of the textbox is actually sent in the postback. But the linkbutton doesn't send anything back to the server. If you need to send something back that gets changed on the client, you'd need to set a hidden field and then modify your linkbutton using that value.
i have one page to design. in this it includes an , password text box,
My requirment is that when an user hit the submit button without entering any data, then it shows a message in red color at side of both the text box as "Cannot be empty"
How it can be done without using Javascript?
In this instance you would use a RequiredFieldValidator control, drop that in your page. It will by default use javascript and server side. You can turn the javascript off by setting the EnableClientScript property to false. You'd associate this validator with your text box using the ControlToValidate property. Set the Text property to the message you want to display.
On the server side event generated by your button simply call the Page's IsValid property and only if it is valid continue processing.
See Validating Form Input Controls.
I found this tutorial at http://social.msdn.microsoft.com/Search/en-US/?query=asp.net%20validation&ac=8.
You can use validation controls. They support client side and server side validation.
You don't need to know javascript if you mean that.
In ASP.Net you can have Validators.
http://www.dotnetcurry.com/ShowArticle.aspx?ID=121&AspxAutoDetectCookieSupport=1
Short but true =)
I have a form that I need the user to be able to type something in a textbox, after they tab out have them enter the same value in another textbox in proximity to it to assure they entered it incorrectly. After that, the second textbox is to disappear and they will continue to the next field without ever having a postback.
Does anyone have any recommendations on how to do this most efficiently? Is there a control that will facilitate this for me?
You can do it by javascript easily. on the onblur or onchange clientside events you should check two textbox's values.
An alternative option : maybe you want to use CompareValidator to compare values of your form elements. Don't forget to set EnableClientScript=true and use ValidationSummary control.