Basic Base64 Encoded Image Viewer
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VB.NET code for Base64 Encoding and Decoding of Image files
Introduction
In my recent project, I was looking for a tool to convert the Base64 Encoded string stored in my database to image and vice versa. After a lot of searching on Google, I realized that it would be faster for me to write this code and also share it with the community.
The project which I wrote is called Base64ImageViwer. The project has two core methods:
- First method:
GetImageFromBase64(ByVal Base64String) As Bitmap - Second method:
ConvertImageToBase64(ImageInput As Image) As String
Using the Code
There are two functions in the code, one for converting Base64 string to image and the other for converting image to Base64 Encoded string. The implementation is done using a Windows Forms application in .NET 4.5 using VB.NET.
Class
Implementation of GetImageFromBase64, ConvertImageToBase64:
''Class for Encoding and Decoding Base64 String
Imports System.IO
Public Class Base64Codec
''Function to Get Image from Base64 Encoded String
Public Function GetImageFromBase64(ByVal Base64String) As Bitmap
Dim fileBytes As Byte()
Dim streamImage As Bitmap
Try
If (String.Empty <> Base64String) Then''Checking The Base64 string validity
fileBytes = Convert.FromBase64String(Base64String)''Convert Base64 to Byte Array
Using ms As New MemoryStream(fileBytes)''Using Memory stream to save image
streamImage = Image.FromStream(ms) ''Converting image from Memory stream
If Not IsNothing(streamImage) Then
''Save image to temp path
streamImage.Save(Path.GetTempPath(), System.Drawing.Imaging.ImageFormat.Jpeg)
End If
End Using
End If
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
Return streamImage
End Function
''Convert the Image from Input to Base64 Encoded String
Public Function ConvertImageToBase64(ImageInput As Image) As String
Dim Base64Op As String = String.Empty
Try
Dim ms As MemoryStream = New MemoryStream()
ImageInput.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)''Temp saving the stream image
Base64Op = Convert.ToBase64String(ms.ToArray())
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
Return Base64Op
End Function
End Class
This class is the implementation class for Base64 string to image and Image to Base64 string. This class is an implementation which has two public functions for Base64 string codec.
Usage
Imports System.IO
Public Class frmImageViwer
Dim objBase64Codec As New Base64Codec ''Object of class Base64Codec
Dim ButtonToolTip As New ToolTip ''Tool tip for up and down buttons
'' Base64 to Image Converter Button click Event
Private Sub btnDownConv_Click(sender As Object, e As EventArgs) Handles btnDownConv.Click
Try
''Get the image path from Path Browsed using Browse Button
PictureBoxImage.Image = _
objBase64Codec.GetImageFromBase64(txtBase64Input.Text)''Decode
txtfilename.Text = Path.GetTempPath() + _
"\TempImg.jpg" ''Assigning a Temp Path
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
End Sub
''Image to Base64 Converter Button click Event
Private Sub btnUpConv_Click(sender As Object, e As EventArgs) Handles btnUpConv.Click
Try
Dim ImageInput As Image = _
Image.FromFile(txtfilename.Text) ''Getting Image from path
txtBase64Input.Text = _
objBase64Codec.ConvertImageToBase64(ImageInput)''Encode
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
End Sub
Private Sub btnBrowse_Click(sender As Object, e As EventArgs) Handles btnBrowse.Click
Dim openFileDialog1 As New OpenFileDialog()''Open File Dialgoue fro Browsing file
Try
openFileDialog1.InitialDirectory = Path.GetTempPath()
openFileDialog1.Filter = "jpeg files (*.jpg)|*.jpg|All files (*.*)|*.*"
openFileDialog1.FilterIndex = 2
openFileDialog1.RestoreDirectory = True
If openFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
txtfilename.Text = openFileDialog1.FileName
PictureBoxImage.Image = _
Image.FromFile(txtfilename.Text)''Setting Image of Picture Box
End If
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
End Sub
''For Deleting Temp file created
Private Sub ClearFile()
Try
Dim TempFile As String = Path.GetTempPath() + "\TempImg.jpg"
File.Delete(TempFile)
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
End Try
End Sub
Private Sub frmImageViwer_FormClosed_
(sender As Object, e As FormClosedEventArgs) Handles MyBase.FormClosed
ClearFile()
End Sub
''For making Textbox Select All enable
Private Sub txtBase64Input_KeyPress_
(sender As Object, e As KeyPressEventArgs) Handles txtBase64Input.KeyPress
If Asc(e.KeyChar) = 1 Then
With txtBase64Input
.SelectionStart = 0
.SelectionLength = Len(.Text)
e.Handled = True
End With
End If
End Sub
''Show Tool Tip Text on Mouse Enter
Private Sub btnUpConv_MouseEnter_
(sender As Object, e As EventArgs) Handles btnUpConv.MouseEnter
ButtonToolTip.Show("Convert Image to Base64", btnUpConv, 30, 0, 1000)
End Sub
''Show Tool Tip Text on Mouse Enter
Private Sub btnDownConv_MouseEnter_
(sender As Object, e As EventArgs) Handles btnDownConv.MouseEnter
ButtonToolTip.Show("Convert Base64 to Image", btnDownConv, 30, 1, 1000)
End Sub
End Class
The Windows Form implementation has two buttons, a down arrow button which is used to convert Base64 Encoded string to Image and show that image in picture box, any errors in string will throw an exception in a message box and another button is up arrow button which is used to convert image in picture box to Base64 string. The image is browsed using the browse button which will pop up a file browser. This version of the code only supports .jpeg image files. The two buttons have a tooltip text. A temp path is assigned for saving the image temporarily after the form is closed, then temp file is deleted.