How-To Guides
Step-by-step tutorials covering common upload scenarios with CoreUpload for ASP.NET Core.
Using CoreUpload in ASP.NET Core
A comprehensive guide to integrating CoreUpload into an ASP.NET Core application. Covers installing the NuGet package, registering Tag Helpers, configuring middleware in Program.cs, and rendering the upload component in Razor Pages using the built-in Tag Helper syntax.
Save Files into SQL Server Database
Learn how to configure CoreUpload to store uploaded files directly in a SQL Server database using the built-in SQL provider. This guide covers setting up the connection string, configuring the provider in Program.cs, and creating the required database table schema for storing file metadata and binary content.
Upload Images with Validation and Thumbnails
Set up image-specific uploads with file type validation, automatic thumbnail generation, and image preview. This guide walks through restricting uploads to image formats (JPEG, PNG, GIF, WebP), generating server-side thumbnails at configurable dimensions, and displaying live previews in the browser before upload.
Client-Side Image Resize Before Upload
Resize images in the browser before they leave the client. Configure maximum width, height, quality, and output format (JPEG, PNG, or WebP). Choose a resize mode (contain, cover, or fill) to control how the image fits the target dimensions. Dramatically reduce upload size for photo-heavy workflows.
Crop, Rotate, and Watermark Images
Use the built-in image processing pipeline to crop images to a fixed aspect ratio, rotate by any angle, flip horizontally or vertically, and stamp a text watermark. All processing happens client-side in the Canvas API with zero server load.
Read EXIF Data and Auto-Orient Photos
Extract EXIF metadata (camera model, date taken, GPS coordinates, orientation) from JPEG files. Enable auto-orient so photos from mobile devices display in the correct rotation automatically, without relying on CSS or server-side image libraries.
Enable MIME Type Checking
Improve upload security by validating file MIME types via magic bytes on the client side and on the server. This guide explains how to configure allowed MIME types, reject files that do not match their declared extension, and combine MIME validation with file extension filtering for defense-in-depth security.
Chunked Upload for Large Files
Enable chunked uploading to handle large files reliably. This guide covers configuring chunk size, enabling automatic retry on failure, resuming interrupted uploads, and adjusting server-side limits in Kestrel and IIS to accommodate large file transfers without timeouts.
Pause, Resume, and Retry Uploads
Give users full control over the upload queue. Pause any in-progress upload and resume it later without losing progress. Configure automatic retry with exponential backoff for transient network failures. Persist queue state to localStorage so uploads survive page refreshes.
Enable Dark Mode
CoreUpload includes full dark mode support. When the user or OS switches to dark mode, every UI component (progress bars, toasts, lightbox, confirmation dialogs) adapts automatically. Override dark-mode CSS variables for a custom dark theme.
Localize the Upload UI
Every user-facing string in the uploader is externalized into a locale object. Pass your own translations for any language. Switch locales at runtime without reinitializing the component. Ideal for multi-language applications.
Upload to Azure Blob Storage or AWS S3
Forward uploaded files from your ASP.NET Core upload handler to cloud storage. This guide shows how to stream files to Azure Blob Storage or AWS S3 without buffering the entire file in memory, keeping your server footprint low even for large uploads.