Custom Previews for File Upload Questions

SurveyJS File Upload questions support the file preview functionality out of the box (see the File Upload demo). This example demonstrates how you can override this functionality and implement custom file previews if required.

To implement custom file previews, follow the steps below:

1. Disable built-in file previews.
   Set the File Upload question's showPreview property to false.

2. Implement a custom file preview component.
   In this demo, a custom component adds a <div> element to the bottom of the question. When users select one or multiple files for upload, this <div> displays "Download file" and "Remove file" buttons per uploaded file.

3. Register your custom component under the sv-file-preview name.
   In HTML/CSS/JavaScript projects, register the component in ReactElementFactory as shown in the index.js file.
   In React, register the component in ReactElementFactory as shown in the FilePreviewComponent.jsx file.
   In Angular, register the component in AngularComponentFactory as shown in the file-preview.component.ts file.
   In Vue 2, components are registered on creation. Make sure to specify "sv-file-preview" as the component name.
   In Vue 3 and Knockout, use techniques native to these libraries:

   • Component Registration in Vue 3
   • Component Registration in Knockout

In this demo, files are uploaded to SurveyJS servers from where they are then deleted after a predefined period of time. We strongly encourage you to use your own servers for file uploads when you use SurveyJS to collect sensitive respondent data in your application.