In this article I will explain with an example, how to convert Image file to Base64
encoded string in C# and VB.Net.
HTML Markup
<form id="form1" runat="server">
<asp:FileUpload ID="FileUpload1" runat="server" />
<asp:Button ID="btnUpload" runat="server" Text="Upload"
onclick="btnUpload_Click" />
<hr />
<asp:Image ID="Image1" Visible = "false" runat="server" Height = "100" Width = "100" />
</form>
Above you will see a FileUpload control to upload the Image File, a Button control to trigger the File upload process and an Image control to display the uploaded image file.
Converting
Image file to Base64 encoded string using C# and VB.Net
When the Upload button is clicked, the Image file is read into a Byte Array using the BinaryReader class object.
The Byte Array is then converted into Base64 encoded string using the Convert.ToBase64String method.
Finally the Base64 encoded string is displayed on web page as Image using Image control.
C#
protected void btnUpload_Click(object sender, EventArgs e)
{
System.IO.Stream fs = FileUpload1.PostedFile.InputStream;
System.IO.BinaryReader br = new System.IO.BinaryReader(fs);
Byte[] bytes = br.ReadBytes((Int32)fs.Length);
string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
Image1.ImageUrl = "data:image/png;base64," + base64String;
Image1.Visible = true;
}
VB.Net
Protected Sub btnUpload_Click(sender As Object, e As EventArgs)
Dim fs As System.IO.Stream = FileUpload1.PostedFile.InputStream
Dim br As New System.IO.BinaryReader(fs)
Dim bytes As Byte() = br.ReadBytes(CType(fs.Length, Integer))
Dim base64String As String = Convert.ToBase64String(bytes, 0, bytes.Length)
Image1.ImageUrl = "data:image/png;base64," & base64String
Image1.Visible = True
End Sub
Demo
Downloads
