convert file to base64 function output

问题

Public Function ConvertFileToBase64(ByVal fileName As String) As String

    Dim ReturnValue As String = ""

    If My.Computer.FileSystem.FileExists(fileName) Then
        Using BinaryFile As FileStream = New FileStream(fileName, FileMode.Open)
            Dim BinRead As BinaryReader = New BinaryReader(BinaryFile)
            Dim BinBytes As Byte() = BinRead.ReadBytes(CInt(BinaryFile.Length))
            ReturnValue = Convert.ToBase64String(BinBytes)
            BinaryFile.Close()
        End Using
    End If
    Return ReturnValue
End Function

The questions I want to ask:

1. I want the output that is I want to convert a text file "C:\Users\user\Desktop\rats\test\test.txt" to base64
2. I was unable to get any output when i converted "test.txt" to base64
3. I use filename="textbox1.text" to add my "test.txt"

回答1:

   Public Function ConvertFileToBase64(ByVal fileName As String) As String
        Return Convert.ToBase64String(System.IO.File.ReadAllBytes(fileName))
    End Function

来源：https://stackoverflow.com/questions/10739264/convert-file-to-base64-function-output