I need to validate various ASP.NET controls, but instead of displaying the standard text/asterisk/image next to each when validation fails, I need to display custom content (change the outline color of the input textbox, display a tooltip, etc.). I could use a standard validation control in most cases (e.g., RequiredFieldValidator for a TextBox), except for the display when validation fails.
I've started out creating CustomValidators, but I need to do this many times for various validations (required field, regular expressions, ranges). It seems a waste to recreate the logic of these validators only so that it can change the response output. The MS documentation at http://msdn.microsoft.com/en-us/library/3w0bs977.aspx says a custom response can be done on both client and server in this case: "On both the client and server side you can create a custom response, such as a color change in a control or a font change for text on a label." It gives an example for the server side, but does not give a method for the client side. What is the best way to handle the custom response on the client?
This article might help you:
http://msdn.microsoft.com/en-us/library/aa479045.aspx
Particularly this section (look for "Client Side Validation" then under there, "Special Effects"):
<asp:Label id=lblZip runat=server
Text="Zip Code:"/>
<asp:TextBox id=txtZip runat=server
OnChange="txtZipOnChange();" /></asp:TextBox><br>
<asp:RegularExpressionValidator id=valZip runat=server
ControlToValidate=txtZip
ErrorMessage="Invalid Zip Code"
ValidationExpression="[0-9]{5}" /><br>
<script language=javascript>
function txtZipOnChange() {
// Do nothing if client validation is not active
if (typeof(Page_Validators) == "undefined") return;
// Change the color of the label
lblZip.style.color = valZip.isvalid ? "Black" : "Red";
}
</script>
There is still some wiring up that needs to be done, which you may be able to tidy up with some jQuery or the like
Related
I am using latest DevEx Asp.net controls. In one of my pages, I have a form with AspxLabels and AspxTextBoxes. In certain textboxes I have a required field validation. I also have 2 check boxes on the page when clicked they populate certain textboxes with data from server.
Here is when the problem occurs.
When any of the check boxes are clicked, I make all textboxes that would be populated from server set to empty string. Then I set the data.
If one of the required fields already has some data, then setting it to empty string when checkbox is checked causes client side validation to kick in and server call to get the data is not done.
Does anyone have any idea how to approach and solve this problem?
Based on your description (aspx would make it more clear) you should set ValidationSettings.ValidateOnLeave to false and validate editor manually.
Here is sample from devex code central article:
<input type="button" value="Validate" onclick="tbTextBox2.Validate();" />
<dx:ASPxTextBox ID="tbTextBox2" runat="server" ClientInstanceName="tbTextBox2">
<ValidationSettings ValidateOnLeave="False">
<RequiredField IsRequired="True" ErrorText="Field is required." />
</ValidationSettings>
</dx:ASPxTextBox>
For various ways of validating form editor(s) on client side read How to raise validation on the client side.
In a web form there are different asp.net validation controls. Is it possible to check a particular validation control is valid ? For example on leaving focus of textbox, first I will check requiredFieldValidatorUserName is valid ? If it is valid then I will check on server using ajax that this user name is not booked already.
Edit:
Explaination: I want to check validity (that input was valid) of a validation control on client side.
Please guide.
All validator controls implement IValidator which contains the IsValid property.
myValidatorControl.IsValid
The best way would be to use a CustomValidator with client side code, as this will display all the error messages, block form submission and also ensure that the validation is repeated at the server side - remember, just because you have client-side validation available, doesn't mean the user's seen it: Always validate your input at the server as well.
Your CustomValidator would then be coded to call the Ajax methods, and would show the error messages correctly to the client:
<asp:Label ID="UserNameLabel" AssociatedControlID="UserName" runat="server">
UserName *:</asp:Label>
<asp:TextBox ID="UserName" runat="server" />
<asp:RequiredFieldValidator ID="UserNameRequired" runat="server"
ControlToValidate="UserName" EnableClientScript="true"
ErrorMessage="You must supply a username!" />
<asp:CustomValidator ID="UserNameCustom" runat="server"
ControlToValidate="UserName"
ClientValidationFunction="CheckExisting"
OnServerValidate="UserNameCustomValidate"
ErrorMessage="Username already taken" />
And your ClientValidationFunction should look something like:
<script type="text/javascript">
function CheckExisting(source, arguments) {
// Pass the arguments.Value to your AJAX call:
if (ajaxCallUserNameTaken(arguments.Value)) {
arguments.IsValid = false;
}
}
</script>
(Obviously, you'll need to write the ajaxCallUserNameTaken method to call your page method/web service/etc.)
Doing it this way will ensure that the validation methods happen as expected; this will get called whenever the user tabs out of the textbox leaving a value (it won't get called if the textbox is empty), and will ensure that the user can't submit the page until they supply a unique value. You'll also want to create the method referenced in OnServerValidate to ensure that the value's good once it hits the server too - this should call the same code that the AJAX endpoint uses to reduce duplication of code, etc.
I was originally going to suggest that you could use the Page_Validators object on the client-side to do some checking in the onBlur event, but I don't really think this is suitable here as it results in more pain:
It assumes that although there might be more than one validator on the page, there's only the RequiredFieldValidator on the control we're checking
The RequiredFieldValidator isn't fired during OnBlur if a user moves out of a control without setting a value - only if they set and clear the value, so even if isvalid is true, you need to check for an empty string!
You could do this by setting the ValidationGroup for the Validator control that you want to treat as separate from the others. Make sure it matches the ValidationGroup of the control it's validating (your username field).
I have just faced the same issue and I Set CausesValidation="true" to the textbox control and it worked. Just give it a try :)
I have been messing around with this around for a bit and found a rather easy (not so efficient) solution to handle this using jQuery.
Use this function to check the validity of your control:
function validateControl() {
return $('#YOUR_VALIDATOR_ID').css("visibility") == "visible"
if you're using Display="Dynamic" on your validator then the function is like so:
function validateControl() {
return return $('#YOUR_VALIDATOR_ID').css("display") == "inline"
Be sure to check the true ID of your validator if you're using a Masterpage, as it will be different than the one in your IDE. Do so by viewing the page source in your browser.
The best solution will be of course to validate your form in some other way, using JavaScript or a CustomValidator that lets you write your own code.
I have an ASP button for which I have set the OnClientClick property to display a javascript confirm message. However, I only want this message to be displayed AFTER all of the client side validations have passed.
How can I do this? Essentially, I believe that I need to force Page level validation from the client and then, only if it passes, display the confirmation box.
If you're using the ASP.NET validation controls add an OnClientClick like this to your submit button...
<asp:Button ID="blah" OnClientClick="if(Page_ClientValidate())return confirm('your message')" OnClick="your submit method" Text="submit" runat="server" />
...Page_ClientValidate() will return true if the page is validated then you need to return the results of your "confirm" in order for the form to be submitted.
There's something along these lines available here: http://www.codeproject.com/KB/aspnet/JavascriptValidation.aspx
I use ASP.NET and have a label control on my page, which I fill with
the jQuery-Command
$('#<%= myLabel.ClientID %>').html(content);
.val() does not seem to work with this.
Somehow, I have Problems getting the content in code-behind. In the code, the myLabel.Text-Property is still empty.
If you want to display the value on the client and have it available on the page, you need an input that'll get sent to the code-behind when you POST like this:
$('#<%= myLabel.ClientID %>').html(content);
$('#<%= myInput.ClientID %>').val(content);
<asp:Label Id="myLabel" runat="server" />
<asp:HiddenField ID="myInput" runat="server" />
In the code-behind:
myInput.Value
I think your problem is that labels (rendered as span tags) are inherently read-only in the asp.net world. They're not meant to be used as 'input' controls, and as such changes to their HTML on the client-side are ignored on the server-side, where values are set based on ViewState.
To do what you are asking, you'd have to notify the server of the change as well, such as by using AJAX. The only issue here is ajax webmethods in your code behind are static, and because of this can't access the page's control set to change the .Text value.
In the end the easiest option is to make use of hidden fields as Nick said. These are technically 'input' controls and their values changed on the client-side are sent to the server as you desire. You'd just have to keep the label/span and hidden field/input synchronized on the client.
Hope this helps.
The following .NET 3.5 code, placed in an aspx file, will trigger a JavaScript error when the page is loaded (for users who have JavaScript enabled):
<noscript>
<asp:TextBox ID="txt" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="txt_RequiredFieldValidator" runat="server"
ControlToValidate="txt"></asp:RequiredFieldValidator>
<asp:Button ID="btn" runat="server" Text="Button" />
</noscript>
The error happens because the JavaScript generated by the ASP.NET validator control does not contain a null check on before the second code line below:
var ctl00_body_txt_RequiredFieldValidator =
document.all ?
document.all["ctl00_body_txt_RequiredFieldValidator"] :
document.getElementById("ctl00_body_txt_RequiredFieldValidator");
ctl00_body_txt_RequiredFieldValidator.controltovalidate = "ctl00_body_txt";
Can anyone suggest a workaround to this?
Footnote: Why am I doing this? For my non-JavaScript users I am replacing some AJAX functionality with some different UI components, which need validation.
You should add the following to the RequiredFieldValidator:
enableclientscript="false"
Seeing as you are using these in <noscript> tags, there is no point in supplying client side vaildation of the controls - they are only going to display if JS is turned off.
This will force the validation to happen (automatically) on the server side for you.
Just make sure you call "Page.IsValid" before you process the response.
See BaseValidator.EnableClientScript for more details.
The javascript is looking for an element contained in the noscript? AFAIK there's no clean way to detect script support from the server side.
I think you'll need to build in a redirect (I've seen this done with a meta-refresh in a header noscript if you don't mind a validation failure) to push noscript users to a "please turnscript on page" or do some surgery to loosen up the validation/control binding which may take some amount of wheel reinventing. This is one of those areas where asp.net's tight coupling between controller and view really punishes.