How to validate an Excel XLSX Spreadsheet using C# in .NET Framework

We have two possibilities for today’s post: We could spend hours going through the code necessary to validate spreadsheets from scratch, or we could spend a couple minutes accomplishing the same goal using a free API. I think we will go with the second option. Let’s dive in.

First we need to install the API client using the Package Manager console and the following snippet:

Install-Package Cloudmersive.APIClient.NET.DocumentAndDataConvert -Version 1.3.4

Next, simply call ValidateDocumentXlsxValidation with the file in question:

using System;
using System.Diagnostics;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Api;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Client;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Model;
namespace Example
public class ValidateDocumentXlsxValidationExample
public void main()
// Configure API key authorization: Apikey
Configuration.Default.AddApiKey("Apikey", "YOUR_API_KEY");
// Uncomment below to setup prefix (e.g. Bearer) for API key, if needed
// Configuration.Default.AddApiKeyPrefix("Apikey", "Bearer");
var apiInstance = new ValidateDocumentApi();
var inputFile = new System.IO.Stream(); // System.IO.Stream | Input file to perform the operation on.
// Validate a Excel document (XLSX)
DocumentValidationResult result = apiInstance.ValidateDocumentXlsxValidation(inputFile);
catch (Exception e)
Debug.Print("Exception when calling ValidateDocumentApi.ValidateDocumentXlsxValidation: " + e.Message );

Seriously, it’s that easy. Your output will look like this:

"DocumentIsValid": true,
"ErrorCount": 0,
"WarningCount": 0,
"ErrorsAndWarnings": [
"Description": "string",
"Path": "string",
"Uri": "string",
"IsError": true

Our API also supports validating DOCX and PPTX files as well using similar functions, along with format conversion, file editing, and much more.

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There’s an API for that. Cloudmersive is a leader in Highly Scalable Cloud APIs.

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