Downloading an Excel file from a byte array is a standard task in C# development, whether you are building a web application or a desktop tool. The process generally involves taking binary data—often generated by libraries like EPPlus , ClosedXML , or IronXL —and sending it to the user's browser or local file system. How to Download in ASP.NET Core MVC & Web API
: The C# code sends the byte array (often as a Base64 string) to a JavaScript function. download excel file from byte array c#
Blazor requires a different approach because it cannot directly trigger a browser download from C# code. You must use to handle the final download step. Downloading an Excel file from a byte array
In modern web development, the most common way to handle this is via a Controller action that returns a FileResult . Blazor requires a different approach because it cannot
: Use a library to create your Excel workbook and convert it into a byte array.
For WinForms, WPF, or Console apps, you don't "download" the file so much as "save" it. The simplest method is using the System.IO.File class. ASP.NET Core Blazor file downloads - Microsoft Learn
public IActionResult DownloadExcel() { byte[] fileContents; // Your byte array logic here string fileName = "Report.xlsx"; string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; // Return the byte array as a downloadable file return File(fileContents, contentType, fileName); } Use code with caution. Downloading in Blazor