Export From Excel Into .txt file [C#]

I know this is an older post, but for those still looking for this functionality, you can use the LEADTOOLS Document SDK technology in your application.

https://www.leadtools.com/sdk/products/document

You can leverage the DocumentConverter class, to convert Excel files to TXT files.

Here is some sample code:

string file = @"FILE PATH TO INPUT MS EXCEL FILE";
string outFile = @"FILE PATH TO OUTPUT TXT FILE";

using (DocumentConverter docConverter = new DocumentConverter()) 
{ 
    DocumentConverterJobData jobData = DocumentConverterJobs.CreateJobData(file, outFile, DocumentFormat.Text); 
    jobData.JobName = "Convert to TXT Job"; 
 
    DocumentConverterJob job = docConverter.Jobs.CreateJob(jobData); 
    docConverter.Jobs.RunJob(job); 
 
    if (job.Errors.Count > 0) 
        foreach (var error in job.Errors) 
            Console.WriteLine($"Error during conversion: {error.Error.Message}\n"); 
    else 
        Console.WriteLine($"Successfully Converted {file} to {outFile}\n"); 
}