Validate a Selection of Files for Upload
Environment
| Product | Telerik UI for ASP.NET Core Upload |
| Operating System | All |
| Browser | All |
| Browser Version | All |
Description
How can I validate if a file is selected for upload when working with the Telerik UI for ASP.NET Core Upload?
Solution
- Initialize the Kendo UI Validator and provide a custom rule which validates whether a file in the Upload is selected.
var validator = $("#myForm").kendoValidator({
rules: {
upload: function(input) {
if (input.attr('name') == "files") {
var uploadControl = $("#files").data("kendoUpload"); //get a reference of the Upload component
var uploadedFiles = uploadControl.getFiles(); //get the uploaded files
return uploadedFiles.length > 0; //assert if there are any files selected
}
return true;
}
}
}).data("kendoValidator");
- Create the Upload component within the Form.
<form id="myForm" method="post">
@(Html.Kendo().Upload()
.Name("files")
.Messages(m => m.Select("Select Files"))
.HtmlAttributes(new {validationmessage = "File is required" })
.Validation(validation => validation
.MaxFileSize(10485760)
.MinFileSize(30720)
)
)
<span class="k-invalid-msg" data-for="files"></span>
<input type="submit" id="submitForm" class="k-button k-button-solid-base k-button-solid k-button-md k-rounded-md" />
</form>
Validate on form submission whilst preventing the default behavior.
$(document).ready(function () {
$("#submitForm").on("click", function (e) {
e.preventDefault();
var validator = $("#myForm").data("kendoValidator");
if (!validator.validate()) {
$("#validationSummary").html("<div class='k-messagebox k-messagebox-error'>Oops! There is invalid data in the form.</div>");
}
else {
$("#validationSummary").html("<div class='k-messagebox k-messagebox-success'>Hooray! Your form is valid!</div>");
}
});
});
For the complete example, refer to the following Telerik REPL example:
<div id="validationSummary"></div>
<form id="myForm" method="post">
@(Html.Kendo().Upload()
.Name("files")
.Messages(m => m.Select("Select Files"))
.HtmlAttributes(new {validationmessage = "File is required" })
.Validation(validation => validation
.MaxFileSize(10485760)
.MinFileSize(30720))
)
<span class="k-invalid-msg" data-for="files"></span>
<input type="submit" id="submitForm" />
</form>
<script>
var validator = $("#myForm").kendoValidator({
rules: {
upload: function(input) {
if (input.attr('name') == "files") {
var uploadControl = $("#files").data("kendoUpload");
var uploadedFiled = uploadControl.getFiles();
return uploadedFiled.length > 0;
}
return true;
}
}
}).data("kendoValidator");
$(document).ready(function () {
$("#submitForm").on("click", function (e) {
e.preventDefault();
var validator = $("#myForm").data("kendoValidator");
if (!validator.validate()) {
$("#validationSummary").html("<div class='k-messagebox k-messagebox-error'>Oops! There is invalid data in the form.</ div>");
}
else {
$("#validationSummary").html("<div class='k-messagebox k-messagebox-success'>Hooray! Your form is valid!</div>");
}
});
});
</script>