C# - Apply Client Side Validation On Fileupload Control To Check Filename Contain Special Character?
May 24, 2010
I am working on ASP.NET3.5 platform. I have used a file upload control and a asp button to upload a file. Whenever i try to upload a file which contain special characterlike (file#&%.txt) it show crash and give the messeage "Server Error in 'myapplication' Application." A potentially dangerous Request.Files value was detected from the client (filename="...New Text &#.txt"). Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. You can disable request validation by setting validateRequest=false in the Page directive or in the configuration section. However, it is strongly recommended that your application explicitly check all inputs in this case.
Exception Details: System.Web.HttpRequestValidationException: A potentially dangerous Request.Files value was detected from the client (filename="...New Text &#.txt"). Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. how can i prevent this crash using javascript at client side?
Public Sub CustomValidator1_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate ' Get file name Dim uploadAvatar As FileUpload = DirectCast(AdvertisementForm.FindControl("uploadAvatar"), FileUpload) Dim UploadFileName As String = uploadAvatar.PostedFile.FileName If UploadFileName = "" Then ' There is no file selected args.IsValid = False Else Dim Extension As String = UploadFileName.Substring(UploadFileName.LastIndexOf(".") + 1).ToLower() If Extension = "xls" Or Extension = "xml" Then args.IsValid = True ' Valid file type Else args.IsValid = False ' Not valid file type End If End If End Sub <table> <div> <td><asp:FileUpload ID="uploadAvatar" runat="server" /></td> <td><asp:LinkButton ID="BtnUpdate" runat="server" CausesValidation="True" CommandName="Update" Text="Update" CssClass="updatebutton" OnClientClick="ValidateFileUpload();" /></td> <asp:CustomValidator ID="CustomValidator1" runat="server" ClientValidationFunction="ValidateFileUpload" ErrorMessage="Please select valid .jpg or .bmp file" ></asp:CustomValidator> <td><asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel" CssClass="cancelbutton" /></td> </tr> </div> </table>
want to know that can we validate a control which is out side a form element in asp.net(server side validation)and outside a form element in html(client side validation) let's take a closer look
I am using ASP MVC 2 RC2 and playing with client side validation. my problem is that i have a form which has a checkbox and text box.
the textbox should be validated only if the checkbox is checked. I was nto able to find anyway to disable the client side validation when the checkbox is not checked.
I'm interested in identifying a means to verify the server-side validation is performing as expected, but need to bypass the client-side validation being done using ASP.NET validation controls. To test this, I've tried using the form Poster add-on to Firefox that allowed me to get/modify the page contents and post it, but the .NET framework interpreted the submission as harmful and threw an application error ("A potentially dangerous Request.Form value was detected from the client").I've created a WinForm that includes a WebBrowser control and I'm able to manipulate the contents of the web page and invoke the button click, but am interested in seeing how to allow a postback with invalid input values. I don't want to assume the server-side validation works (even though I do check if Page.IsValid on the server on postback).This submits the web form in the WebBrowseer control and the expected client-side validation fires: extendedWebBrowser1.Document.GetElementById(formButtonName).InvokeMember("click"); This is how I've manipulated some of the page contents (this just prevents submission): mshtml.IHTMLDocument2 doc = extendedWebBrowser1.Document.DomDocument as mshtml.IHTMLDocument2; string html = doc.body.innerHTML; html.Replace("Page_ValidationActive = false", "Page_ValidationActive = true"); doc.body.innerHTML = html.ToString(); extendedWebBrowser1.Document.GetElementById(formButtonName).InvokeMember("click");
I have a textbox in my application which has multiple validation on it e.g. RequiredFieldValidator, RegexValidation and CustomValidation. My page has several similar textboxes. So I just copy-paste and change id and controltovalidate properties and it is working.
Since similar tbxs are going to be used on another page as well, I think it would be nice to create my own custom TextBox control with built-in validation.
Here are two approaches I have found and tried:
1: Implement from IValidator perform my custom validation in Validate Method. As shown here: Self-Validating TextBox But it does not show how to implement client-side validation.
2: Create custom control that derives from TextBox and add asp.net built-in validators I need. As shown here:Custom TextBox. I tried the code and it works server/client side.
I like the first approach but don't know how to implement client-side validation. I know I need a client-side js function. I can do that. I know how to include my js file using Page.ClientScript class but don't know how to integrate all together and make it work.
I can create a UserControl or the second approach above but for now I am specifically looking to learn and implement client-side validation from custom control.
I have a FileUpload control that currently uploads pics to the Photos folder on my server. What I would like to know is how would I give it a randomly generated filename when it gets uploaded? As I don't want duplicates later on down the line. Cheers.(Code below).
Please help to understand this RegEx statement in details. It's supposed to validate filename from ASP.Net FileUpload control to allow only jpeg and gif files. It was designed by somebody else and I do not completely understand it. It works fine in Internet Explorer 7.0 but not in Firefox 3.6.
I have a async file upload control and I am doing client side validation for Image."OnClientuploadstarted" I am doing the client side validation.My validation is working fine but my problem is that the file upload control text box goes green (i.e file is loaded on the server) even if the validation fails which is I dont want.What I want is when the client side validation fails the file does not gets loaded on the server and the Async file upload textbox does not goes green.I have goggled but have not found a suitable solution.
I have a user control which contains a CustomValidator which is used according to whether a RadioButton is checked or not (there are several RadioButtons, I'm only showing the relevant one)
There is some client + server side validation code (the server side code does exactly the same thing and is skipped for brevity)
<script type="text/javascript"> function ValidateDateFields_Client(source, args) [code]...
There are two instances of this control in the page. When running the client side version it hits the wrong one (the version of the control which is disabled). You can see from the generated HTML both are correctly specified. I'm not sure how .NET works out which clientside function to call given they both have the same name.
[code]... Do i need to add something in to scope it? What's the best way to achieve this? If I disable the loading of the second control everything works fine.
If I enable client side validation in the view I'll get the error per the Attributes from the metadata class. If I take clientside validation out, error gets thrown from saving to the DB rather than return the view with an Error Summary.
This is the top portion of my view....
<% using (Html.BeginForm()) {%> <%: Html.ValidationSummary(true) %>
I've tried running without debugging (ctrl + f5) in debug and release mode as well as setting breakpoints and Debugging (f5) but it just seems weird to get Client side validation without server side validation. What am I missing here?
if in the code behind, I set the label to "You must enter a value if the textbox is empty" to validate it on the server side and this is fine, but if javascript is enabled, I don't want to show the client side validation and the server side label together. Is this something where I would just have to disable the client-side validators if javascript was enabled?
I'd like to implement ajax message box that will gather information from validators on a page when client-side validation fires. Like: I have left some text fields blank then press submit button and appropriate RequiredFieldValidators show messages. I would like my message box shows those messages too. I am looking for appropriate way to hook on validators JS event or something.
I use the oob client side validation from mvc 2 RC. The input field validation errors are working fine. But the validation summary is missing. How to get the validation summary on client side validation?
When i use Validator callout extender and as well both client side java script validation , both are not working at a same time.I use java script code for dynamic checkboxes to be atleast one checkbox must be checked.When i use onclient click only javascript validations are fired, when use onclick function javascript code is not working.
I used the FileUpload and all is ok, I dont have problems, but I need put the path for the upload by default, in the load of the page, or java script,, but the FileUpload. values is only read , how i can change this value? when the user click in browse the choose file, make a filter by the path for default for example seacrh in c:d.... or the box Choose File how i can write the file name by default?
I have an application where the user uploads files.
GOAL:
I need to check the file name for special characters and replace them with an underscore. Is there a Select Statement OR IF Statement I can use to search the fileName for unwanted special charaters; those characters will be replaced with a blank or underscore?
I want to replace ampersand, Number sign, Apostrophe, and so on.
