C# 2008 Programmer's Reference

 txtStatus.Text = 'Signature saved!';
 writer.Close();
 isoStream.Close();
}

Define the DrawSignature() subroutine so that the signature can be reproduced from a string representing a collection of lines:

//---draws the signature---
private void DrawSignature(string value) {
 _lines = new List<List<Point>>();
 //---split into individual lines---
 string[] lines = value.Split('
');
 //---for each individual line---
 for (int i = 0; i <= lines.Length - 2; i++) {
  //---split into individual points---
  string[] ps = lines[i].Split('|');
  _points = new List<Point>();
  //---for each point---
  for (int j = 0; j <= ps.Length - 2; j++) {
   string[] xy = ps[j].Split(',');
   _points.Add(new Point(
    (Convert.ToDouble(xy[0])),
    Convert.ToDouble(xy[1])));
  }
  _lines.Add(_points);
 }
 //---draws the signature---
 for (int line = 0; line <= _lines.Count - 1; line++) {
  _points = (List<Point>)_lines[line];
  for (int i = 1; i <= _points.Count - 1; i++) {
   Line sline = new Line() {
    X1 = _points[i - 1].X,
    Y1 = _points[i - 1].Y,
    X2 = _points[i].X,
    Y2 = _points[i].Y,
    StrokeThickness = 2,
    Stroke = new SolidColorBrush(Colors.Black)
   };
   SigPad.Children.Add(sline);
  }
 }
}

Code the MouseLeftButtonDown event handler for the Load button so that the series of signature lines can be loaded from isolated storage:

//---Load button---
void btnLoad_MouseLeftButtonDown(
 object sender, MouseButtonEventArgs e) {
 IsolatedStorageFile isoStore =
  IsolatedStorageFile.GetUserStoreForApplication();
 IsolatedStorageFileStream isoStream =
  new IsolatedStorageFileStream('IsoStoreFile.txt',
  FileMode.Open, isoStore);
 StreamReader reader = new StreamReader(isoStream);
 //---read all lines from the file---
 string lines = reader.ReadToEnd();
 //---draws the signature---
 DrawSignature(lines);
 txtStatus.Text = 'Signature loaded!';
 reader.Close();
 isoStream.Close();
}

Code the MouseLeftButtonDown event handler for the Clear button so that the signature can be cleared from the drawing pad:

//---Clear button---
void btnClear_MouseLeftButtonDown(
 object sender, MouseButtonEventArgs e) {
 _lines = new List<List<Point>>();
 _points = new List<Point>();
 //---iteratively clear all the signature lines---
 int totalChild = SigPad.Children.Count - 2;
 for (int i = 0; i <= totalChild; i++) {
  SigPad.Children.RemoveAt(1);
 }
 txtStatus.Text = 'Signature cleared!';
}

Press F5 to test the application. You can now sign and then save the signature. You can also load the saved signature (see Figure 19-72).

Figure 19-72

Saving the Signature to Web Services

One of these signatures isn't a lot of good unless you can send it to a Web Service. This section shows you how to do that.

Using the same project created in the previous section, add a new Web Site project to the current solution (see Figure 19-73).

Figure 19-73

Select ASP.NET Web Site, and name the project SignatureWebSite.

Add a new Web Service item to the Web Site project, and use its default name of WebService.asmx (see Figure 19-74).

Figure 19-74

In the WebService.cs file, add the following lines:

using System;
using System.Collections;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.IO;