Convert File to Byte Array and Byte Array to Files

In this article, let us see how to convert a file content to a byte array and restore the original content from the byte array and display it in its original file format such as pdf, doc, xls, rtf, jpeg, png etc.

Step 1: Create an ASP.Net application and add a class Document.

public class Document {
public int DocId { get; set; }
public string DocName { get; set; }
public byte[] DocContent { get; set; }

Step 2: Create a file of format doc/pdf/rtf etc. and convert the file content to a ByteArray using the following method. Then create an object of type Document and assign the Docname and DocContent property values from filename and filecontent.

public Document FileToByteArray(string fileName) {
byte[] fileContent = null;

System.IO.FileStream fs = new System.IO.FileStream(fileName, System.IO.FileMode.Open, System.IO.FileAccess.Read);
System.IO.BinaryReader binaryReader = new System.IO.BinaryReader(fs);
long byteLength = new System.IO.FileInfo(fileName).Length;
fileContent = binaryReader.ReadBytes((Int32)byteLength);
Document = new Document();
Document.DocName = fileName;
Document.DocContent = fileContent;
return Document ;

Step 3: Now we need to convert the byte array back again to the file content and display it to the user with download options. For that I am using another method, ShowDocument, as below:

private void ShowDocument(string fileName, byte[] fileContent)
//Split the string by character . to get file extension type
string[] stringParts = fileName.Split(new char[] { ‘.’ });
string strType = stringParts[1];
Response.AddHeader(“content-disposition”, “attachment; filename=” + fileName);
//Set the content type as file extension type
Response.ContentType = strType;
//Write the file content

Step 4: In the page_load event, I have the following code, which will read the contents from the file and convert it to a ByteArray using the FileToByteArray method and convert it back to content using the ShowDocument method.

protected void Page_Load(object sender, EventArgs e)
FileToByteArray(“C:\\Users\\santhosh.kumar\\Documents\\Test for rht format.rtf”);
ShowDocument(Document.DocName, Document.DocContent);


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