Ajax/Json Asp v2+ Reading the sent Json Data.

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I'm trying to send a canvas to the server machine via Ajax and json but how do I read it?

This is the HTML
-------------------------------------------------------------------------------------------

ASP.NET

<%@ Page Language="C#" AutoEventWireup="True" CodeBehind="WebForm1.aspx.cs" Inherits="WebForm1" %>

<!DOCTYPE HTML>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
	<title>Saving Canvas to .png file on the server</title>
	<script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.2.min.js" temp_src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.2.min.js" type="text/javascript"></script>

	<script type="text/Javascript" language="Javascript">
		function drawShapes() {
			var canvas = document.getElementById("myCanvas");
			var context = canvas.getContext("2d");
			context.fillStyle = "Blue";
			context.fillRect(0, 0, 200, 200);
			context.beginPath();
			context.lineWidth = "4";
			context.strokeStyle = "Green";
			context.fillStyle = "Yellow";
			context.arc(150, 100, 50, 20, Math.PI * 2, false);
			context.stroke();
			context.fill();
		}
	</script>
</head>
<body  önload="drawShapes()">
	<canvas id="myCanvas" width="200" height="200">
	</canvas>
	<input type="button" id="btnSave" name="btnSave" value="Save the canvas to server" />
	<script type="text/javascript">
		// Send the canvas image to the server.
		$(function () {
			$("#btnSave").click(function () {
				var image = document.getElementById("myCanvas").toDataURL("image/png");
				image = image.replace('data:image/png;base64,', '');
				$.ajax({
					type: 'POST',
					url: 'WebForm1.aspx?imageDt=',
					data: '{ "imageData" : "' + image + '" }',
					contentType: 'application/json; charset=utf-8',
					dataType: 'json',
					success: function (msg) {
						alert('Image saved successfully !');
					}
				});
			});
		});

	</script>
</body>
</html>

-------------------------------------------------------------------------------------------

And here is the code behind...

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Web.Script.Services;
using System.Web.Services;
using System.Collections.Specialized;

[ScriptService]
public partial class WebForm1 : System.Web.UI.Page
	{
	static string path = @"e:\Dev\00Test\htmlCanvas\WebApplication1\Files\";

		protected void Page_Load( object sender, EventArgs e )
		{
			if ( Page.IsPostBack )
			{

			}
			else
			{
                                //????Where do I see the stored image data????
				NameValueCollection nvc = Request.Form;

				string s = Request[ "imageData" ];
				System.Web.UI.Page p = ( System.Web.UI.Page )System.Web.HttpContext.Current.Handler;
				if ( s != null )
				{

					btnSave( s );
				}
			}
		}



		[WebMethod]
		public static void btnSave( string imageData )
		{
			string fileNameWitPath = path + DateTime.Now.ToString().Replace( "/", "-" ).Replace( " ", "- " ).Replace( ":", "" ) + ".png";
			using ( FileStream fs = new FileStream( fileNameWitPath, FileMode.Create ) )
			{
				using ( BinaryWriter bw = new BinaryWriter( fs ) )
				{
					byte[] data = Convert.FromBase64String( imageData );
					bw.Write( data );
					bw.Close();
				}
			}
		}

	}

-------------------------------------------------------------------------------------------
The url looks like.......

HTML

http://localhost:55607/WebForm1.aspx?imageDt=

and the json in it looks like (for POST)....

imageData
	"iVBORw0KGgoAAAANSUhEUgAAAMgAAADICAYAAACtWK6eAAANE0lEQVR4nO3dbZDVZRkG8EtajRhGd3RtNiVcyXR1DMmiNsNc0gwYQERQNNIdRKOkZjXGYRD1STJLEDQIVFBQ8CVsfIEibcuVsBA3Wgtpp..................................../MAIp6ZBxDxzDyAiGfmAUQ8Mw8g4pl5ABHPzAOIeGYeQMQz8wAinpkHEPHMPICIZ+YBRDwzDyDimXkAEc/MA4h4Zh5AxDPzACKemQcQ8cw8gIhn5gFE/Po/AQW/NxIF4akAAAAASUVORK5CYII=".

How do I tell the ASP Server to get that data that has been sent to the server?

Posted 1-Sep-13 23:50pm

Serenity1

Updated 2-Sep-13 0:44am

Nelek

v5

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Serenity1 · Accepted Answer · 2013-09-02T00:14:00

This is not the answer I was looking for but it does work. What I wanted is a way to see what the data is that has been send on click.

//This also associates the Servers Post Events from the Clients side to the Server.
//To setup a communication method between the Clients Machine and the server.

ASP.NET

<%@ Page Language="C#" AutoEventWireup="True" CodeBehind="WebForm1.aspx.cs" Inherits="WebForm1" %>

<!DOCTYPE HTML>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
	<title>Saving Canvas to .png file on the server</title>
	<script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.2.min.js" temp_src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.2.min.js" type="text/javascript"></script>

	<script type="text/Javascript" language="Javascript">
		function drawShapes() {
			var canvas = document.getElementById("myCanvas");
			var context = canvas.getContext("2d");
			context.fillStyle = "Blue";
			context.fillRect(0, 0, 200, 200);
			context.beginPath();
			context.lineWidth = "4";
			context.strokeStyle = "Green";
			context.fillStyle = "Yellow";
			context.arc(150, 100, 50, 20, Math.PI * 2, false);
			context.stroke();
			context.fill();
		}
	</script>
</head>
<body  önload="drawShapes()">
	<canvas id="myCanvas" width="200" height="200">
	</canvas>
	<input type="button" id="btnSave" name="btnSave" value="Save the canvas to server" />
	<script type="text/javascript">
		// Send the canvas image to the server.
		$(function () {
			$("#btnSave").click(function () {
				var image = document.getElementById("myCanvas").toDataURL("image/png");
				image = image.replace('data:image/png;base64,', '');
				$.ajax({
					type: 'POST',
					url: 'WebForm1.aspx/UploadImage',  //Must Point to a aspx type page and with the / followed by the name of the method.
					data: '{ "imageData" : "' + image + '" }',
					contentType: 'application/json; charset=utf-8',
					dataType: 'json',
					success: function (msg) {
						alert('Image saved successfully !');
					}
				});
			});
		});

	</script>
</body>
</html>

C#

//Here is the Code Behind

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Web.Script.Services;
using System.Web.Services;
using System.Collections.Specialized;

[ScriptService]
public partial class WebForm1 : System.Web.UI.Page
{
	static string path = @"e:\Dev\00Test\htmlCanvas\WebApplication1\Files\";
	protected void Page_Load( object sender, EventArgs e ){}

	[WebMethod] //This ensures that the server calls this method on post.
	public static void UploadImage( string imageData )
	{
		string fileNameWitPath = path + DateTime.Now.ToString().Replace( "/", "-" ).Replace( " ", "- " ).Replace( ":", "" ) + ".png";
		using ( FileStream fs = new FileStream( fileNameWitPath, FileMode.Create ) )
		{
			using ( BinaryWriter bw = new BinaryWriter( fs ) )
			{
				byte[] data = Convert.FromBase64String( imageData );
				bw.Write( data );
				bw.Close();
			}
		}
	}
}