File Upload in Web Forms — a practical guide to Web Forms file upload with clear examples you can reuse in real projects.
ASP & ASP.NET Tutorial Series (83/247). Prefer one article? Read the complete ASP.NET tutorial.
Short description
Block executable extensions; store outside site root when possible.
FileUpload
if (FileUpload1.HasFile) {
// validate extension/size then SaveAs to safe path
}