Getting empty pdf attachments when trying to create “activitymimeattachment”

问题

I want to attach pdf from url into CRM "activitymimeattachment". Everything works fine but im getting empty pdf attachments (even the size is the same as original pdf). Could it be some problem with Encoding or converting? Maybe somebody could help me with this?

I see that email is created with attachment which is empty, but the size is the same as for original pdf.

Entity attachment = new Entity("activitymimeattachment");
attachment["subject"] = "Attachment";
string fileName = "Invoice.pdf";
attachment["filename"] = fileName;
WebClient wc = new WebClient();
string theTextFile = wc.DownloadString(url);
byte[] fileStream = Encoding.ASCII.GetBytes(theTextFile);
attachment["body"] = Convert.ToBase64String(fileStream);
attachment["mimetype"] = "application/pdf";
attachment["attachmentnumber"] = 1;
attachment["objectid"] = new EntityReference("email", emailguid);
attachment["objecttypecode"] = "email";
service.Create(attachment);

回答1:

I believe the encoding is issue. The PDF is neither a string nor an ASCII file so these lines are at fault:

string theTextFile = wc.DownloadString(url);
byte[] fileStream = Encoding.ASCII.GetBytes(theTextFile);

I would suggest changing your web client to download a binary file i.e. application/pdf and save the file locally e.g to d:\temp\invoice.pdf.

Then you can do this:

var bytes = File.ReadAllBytes(@"d:\temp\invoice.pdf");
var body = Convert.ToBase64String(bytes);

In short, avoid trying to put the PDF into a string, or using the ASCII encoding to get its byte array. It's a binary file until you convert it to Base64.

Of course you can also probably get your web client to download the file into memory and convert it to Base64 without writing the file locally. I just wanted the simplest example to make the point about the encoding.

回答2:

Thank You for advice @Aron. I actually have found a solution which is very simnply. I just used another method from WebClient class. The main thing I needed to change DownloadString(url) method into DownloadData(url) method:

WebClient wc = new WebClient();
byte[] theTextFile = wc.DownloadData(url);
attachment["body"] = Convert.ToBase64String(theTextFile);enter code here

来源：https://stackoverflow.com/questions/55969510/getting-empty-pdf-attachments-when-trying-to-create-activitymimeattachment

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dynamics-crm