Preventing Postback If No File is Selected

[Rodney]

I think I'm doing something wrong here. I have a RadAsyncUpload control and a submit button on the page to cause the postback. All I want to do is prevent the postback if no file has been selected, or have the submit button disabled until a file is selected. If it makes any difference this is all inside of a RadWindow.

Here's the markup for the RadAsyncUpload

<div class="formRow" id="divAttachFile" runat="server" style="height: 60px;">
     <div class="floatLeft">
         <label for="asyncFlUpldAttachment"><span id="spnUploadFileMark" runat="server" class="validator">*</span> Upload File: </label>
         <telerik:RadAsyncUpload ID="RadAsyncUpload1" runat="server" MaxFileSize='<%$ AppSettings:MAXATTCHFILESIZE %>'
             MultipleFileSelection="Disabled" MaxFileInputsCount="1" AllowedFileExtensions='<%$ AppSettings:ATTCHFILEEXTNS %>'
             EnableInlineProgress="true" TemporaryFileExpiration="36000"
             OnClientValidationFailed="validationFailed"
             OnClientFileUploading="fileUploading"
             OnClientFileUploadFailed="fileUploadFailed"
             PostbackTriggers="lnkBtnAttachmentCancel"
             TabIndex="100">
         </telerik:RadAsyncUpload>
         <span id="ErrorHolder" style="display: none" class="validator"></span>
     </div>
 </div>

Here's the current JavaSrcipts, pretty much straight from your samples

<script type="text/javascript">
    var pageIsValid = true;
    function validationFailed(sender, args) {
        $("#ErrorHolder").show();
        var fileExtention = args.get_fileName().substring(args.get_fileName().lastIndexOf('.') + 1, args.get_fileName().length);
        if (args.get_fileName().lastIndexOf('.') != -1) {//this checks if the extension is correct
            if (sender.get_allowedFileExtensions().indexOf(fileExtention) == -1) {
                $("#ErrorHolder").html("Wrong Extension! Verify file.");
            }
            else {
                $("#ErrorHolder").html("The file size exceeds the limit");
            }
        }
        else {
            $("#ErrorHolder").html("Wrong Extension! Verify file");
        }
        sender.deleteFileInputAt(0);
    }

    function fileUploading(sender, args) {
        $("#ErrorHolder").hide();
    }

    function fileUploadFailed(sender, args) {
        $("#ErrorHolder").show();
        $("#ErrorHolder").html("File upload failed for:" + args.get_fileName());
        sender.deleteFileInputAt(0);
    }
</script>

 

Thanks

Rodney

[Ivan Danchev]

Hello Rodney,

Let's say you have the following button, which initiates postback: 

<telerik:RadButton runat="server" ID="RadButton1" Text="Submit" AutoPostBack="true" OnClientClicking="OnClientClicking"></telerik:RadButton>

You can prevent the postback by canceling the click event in the OnClientClicking event handler if no file is selected in the AsyncUpload:

function OnClientClicking(sender, args) {
    var upload = $find("<%=RadAsyncUpload1.ClientID%>");
    var files = upload.getUploadedFiles();

    if (files == 0) {
        args.set_cancel(true);
    }
}

Regards,
Ivan Danchev
Telerik

[Rodney]

Well it sort of worked. I now don't have a problem when I don't have an attachment, but if I do when I hit my codebehind to process it, the attachment isn't there and I get an index out of range referencing the asyncuploadcontrol. I litterally swapped your button for mine and now it won't upload. 

Here's my original code:

<asp:LinkButton ID="lnkBtnSaveAttachment" runat="server" OnClick="lnkBtnSaveAttachment_Click"
    CssClass="silverButton" ValidationGroup="attachmentValidations">

Here's the new button:

<telerik:RadButton ID="rbtSaveAttachment" runat="server" ValidationGroup="attachmentValidations"
    OnClientClicking="OnClientClicking" Text="Save" OnClick="rbtSaveAttachment_Click"></telerik:RadButton>

Here's the codebehind for the OnClick event:

attach.FileTypeCode = StringUtilities.GetFileExtension(RadAsyncUpload1.UploadedFiles[0].GetExtension());

Aside from switching the button with the JavaScript above there is no other change and this line fails everytime. I switch back to the ASP button without the JavaScript and it works other than it doesn't validate the existence of the file.

 

 

 

[Ivan Danchev]

Hello Rodney,

You have set the lnkBtnAttachmentCancel button as a postback trigger (PostbackTriggers = "lnkBtnAttachmentCancel"). When you add the RadButton, which has a different ID, and initiate a postback with it the selected file will not be uploaded (the FileUploaded event will not fire), because the postback is not initiated by a control set as postback trigger. Try setting the RadButton's ID to the PostbackTriggers property.

Regards,
Ivan Danchev
Telerik by Progress