轉自：http://www.codeproject.com/Articles/105570/InkCollector-Signiture-Made-Easy

The following article is useful when trying to import Ink into a database. I have tried to keep it as simple as possible.

I've successfully used this in my Access database that holds about 500 signatures; the average signature size is about 1500 characters. The largest one on record is 2853 and the smallest one on record is 1139. To store this in a Microsoft Access Database, you will need to save it in a memo field as the maximum number of characters in a Text field is 255.

Using the Code

First add the reference for Microsoft.Ink to your VB Project, next create a group box on your form. Before your form class, add Imports Microsoft.Ink so that a InkCollector control can be created. First, define the InkCollector control. Then, create the control from your form load sub

Your code should then look something like this:

Imports Microsoft.Ink 'Required for InkCollector

Public Class frmMain

    Dim Sig_InkCollector As InkCollector 'The InkCollector

    Private Sub frmMain_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
	Handles
 
 Me.Load
        Sig_InkCollector = New InkCollector(GroupBox1.Handle)
        Sig_InkCollector.Enabled = True
        Sig_InkCollector.AutoRedraw = True
    End Sub
End Class

I have just completed adding a function that converts the base64 string to an image so that it can be attached to a RTF, HTML or printed easily.

To Clear the Signiture

Specify call the clear sub from the Signiture module, then specify the InkCollector and the GroupBox which contains the InkCollector control.

Signiture.Clear(Sig_InkCollector, GroupBox1)

To Set the Signiture

To load a signiture Base64 string into the inkCollector, call the following Sub, specify the InkCollector and the GroupBox which contains the InkCollector control, then the Base64 String.

Signiture.SetBase64(Sig_InkCollector, GroupBox1, TextBox1.Text)

To Get the Signiture

To read the Signiture from the InkCollector, call the following function and specify the InkCollector. The Base64 String will be returned.

Textbox1.Text = Signiture.GetBase64(Sig_InkCollector) 

To Convert Base64 to Image

To convert a stored Base64InkSerializedFormat String to an Image, so that the signiture can be displayed in a report.

PictureBox1.Image = Signiture.Base64toImage(TextBox1.Text) 

Source

Imports Microsoft.Ink 'Required for InkPicture
Imports System.Text 'Required by UTF8Encoding
Imports System.IO 'Required by MemoryStream
''' <summary>
''' Signiture Made Easy Module
''' Created by Marco van der Merwe (22 September 2010)
''' </summary>
Module Signiture
''' <summary>
''' Returns String in Format(PersistenceFormat = Base64InkSerializedFormat)
''' </summary>
''' <param name="InkCollector"></param>
''' <returns> String Format(PersistenceFormat = Base64InkSerializedFormat)</returns>
''' <remarks></remarks>
Function GetBase64(ByVal InkCollector As InkCollector) As String
Dim utf8 As UTF8Encoding = New UTF8Encoding()
InkCollector.Enabled = False
Return utf8.GetString(InkCollector.Ink.Save_
	(PersistenceFormat.Base64InkSerializedFormat, CompressionMode.Maximum))
InkCollector.Enabled = True
End Function
''' <summary>
''' Sets the Base 64 Ink from String
''' </summary>
''' <param name="InkCollector"></param>
''' <param name="GroupBox"></param>
''' <param name="Base64"></param>
''' <remarks></remarks>
Sub SetBase64(ByVal InkCollector As InkCollector, _
	ByVal GroupBox As GroupBox, ByVal Base64 As String)
Dim loadedInk As Ink = New Ink()
Dim utf8 As UTF8Encoding = New UTF8Encoding()
InkCollector.Enabled = False
InkCollector.Ink.DeleteStrokes() ' Clear all strokes
loadedInk.Load(utf8.GetBytes(Base64))
InkCollector.Ink = loadedInk
InkCollector.Enabled = True
GroupBox.Invalidate()
End Sub
''' <summary>
''' Clear Signiture
''' </summary>
''' <param name="InkCollector"></param>
''' <param name="GroupBox"></param>
''' <remarks></remarks>
Sub Clear(ByVal InkCollector As InkCollector, ByVal GroupBox As GroupBox)
InkCollector.Enabled = False ' Disable InkPicture to clear
InkCollector.Ink.DeleteStrokes() ' Clear all strokes
GroupBox.Invalidate() ' Redraw frame
InkCollector.Enabled = True ' Reenale InkPicture for entry
End Sub
 
''' <summary>
''' Converts String Format(PersistenceFormat = Base64InkSerializedFormat) 
''' to System.Drawing.Image
''' </summary>
''' <param name="Base64"></param>
''' <returns>System.Drawing.Image</returns>
''' <remarks></remarks>
Function Base64toImage(ByVal Base64 As String) As System.Drawing.Image
Dim utf8 As UTF8Encoding = New UTF8Encoding()
Dim imgSig As System.Drawing.Image
Dim tmploadedInk As Ink = New Ink()
Dim strGIF As String
Dim imageBytes() As Byte
Dim MS As MemoryStream
'Load the Base64 String in Format(PersistenceFormat = Base64InkSerializedFormat) as ink
tmploadedInk.Load(utf8.GetBytes(Base64))
'Convert the ink to Base64 String in format 
'(PersistenceFormat.Gif, CompressionMode.Maximum)
strGIF = Convert.ToBase64String(tmploadedInk.Save_
	(PersistenceFormat.Gif, CompressionMode.Maximum))
'Convert Base64 String to Byte Array
imageBytes = Convert.FromBase64String(strGIF)
MS = New MemoryStream(imageBytes, 0, imageBytes.Length)
' Convert byte[] to Image
MS.Write(imageBytes, 0, imageBytes.Length)
imgSig = Image.FromStream(MS, True)
Return imgSig
End Function
End Module

Points of Interest

I’ve tried everything with InkPicture for about 3 weeks and had no results, until I started using InkCollector. I had many unexplained errors and very little help with InkPicture, this is far easier to use.

I know the Access Database gets quite large, but at least these signitures are secured by a password and my data is at least stored in the same database.

History

• Added Image Support, to convert Base64InkSerializedFormat string to Image