ASPxClientFileManager.FileUploadValidationErrorOccurred Event

Enables you to specify whether the selected file(s) are valid and provide an error text.


FileUploadValidationErrorOccurred: ASPxClientEvent<ASPxClientUploadControlValidationErrorOccurredEventHandler<ASPxClientFileManager>>

Event Data

The FileUploadValidationErrorOccurred event's data class is ASPxClientUploadControlValidationErrorOccurredEventArgs. The following properties provide information specific to this event:

Property Description
errorText Gets or sets the error text.
invalidFiles Returns an array of invalid files.
showAlert Gets or sets a value specifying whether an alert message is displayed when the ASPxClientUploadControl.ValidationErrorOccurred event fires.
validationSettings Gets the validation settings for the selected files.


The FileUploadValidationErrorOccurred event is automatically raised each time a user selects one or several files to upload, and allows you to specify whether these files are valid for the following parameters:

The FileUploadValidationErrorOccurred event is used to customize the error message and provide more information about why the selected file(s) are invalid.


The following example illustrates how to use the ASPxClientFileManager.FileUploadValidationErrorOccurred event to customize an error message for files that didn't pass validation.

    function onUploadControlValidationErrorOccured(s, e) {
        e.showAlert = false;
        var errorHtmlContentTemplate = "<div class=\"error-attention\">Attention!</div><br />" +
            "{0} files are invalid and will not be uploaded.<br /><br /> {1}" +
            "All files listed above have been removed from the selection.";

        var preparedErrorHtmlContent = errorHtmlContentTemplate
            .replace("{0}", e.invalidFiles.length)
            .replace("{1}", getDetailsErrorInfoHtml(e));

    function getDetailsErrorInfoHtml(e) {
        var html = "";
        html += getDetailsErrorInfoHtmlByErrorType(e, ASPxClientUploadControlValidationErrorTypeConsts.MaxFileCountExceeded,
            "These files exceed the allowed file count (the maximum file count is {0}):<br /><ul>{1}</ul><br />",
        html += getDetailsErrorInfoHtmlByErrorType(e, ASPxClientUploadControlValidationErrorTypeConsts.MaxFileSizeExceeded,
            "These files exceed the allowed file size (the maximum file size is {0} bytes):<br /><ul>{1}</ul><br />",
            e.validationSettings.maxFileSize, true);
        html += getDetailsErrorInfoHtmlByErrorType(e, ASPxClientUploadControlValidationErrorTypeConsts.NotAllowedFileExtension,
            "Extensions of these files are not allowed (valid extensions are - {0}):<br /><ul>{1}</ul><br />",
            e.validationSettings.allowedFileExtensions.join(', '));
        html += getDetailsErrorInfoHtmlByErrorType(e, ASPxClientUploadControlValidationErrorTypeConsts.FileNameContainInvalidCharacter,
            "Names of this files contain invalid characters ({0}):<br /><ul>{1}</ul><br />",
        return html;
    function getDetailsErrorInfoHtmlByErrorType(e, errorType, message, commonInfo, isFileSize) {
        var filesInfo = getFilesInfoByErrorType(e.invalidFiles, errorType);
        if (filesInfo.length == 0)
            return "";
        var filesHtml = "";
        for (var i = 0, len = filesInfo.length; i < len; i++) {
            var f = filesInfo[i];
            var fileText = isFileSize ? f.fileName + " - " + f.fileSize + " bytes" : f.fileName;
            filesHtml += "<li class=\"error-file\">" + fileText + "</li>";
        return "<div class=\"error-detail\">" + message.replace("{0}", commonInfo).replace("{1}", filesHtml) + "</div>";
    function getFilesInfoByErrorType(invalidFiles, errorType) {
        var filesInfo = [];
        for (var i = 0, len = invalidFiles.length; i < len; i++) {
            var fileInfo = invalidFiles[i];
            if (fileInfo.errorType == errorType)
        return filesInfo;
See Also