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In ASP.NET WebForms I want to pass arbitrary data from server to client and back again. I am serializing to JSON and have been simply producing JavaScript that creates the object on the client. I have no problem sending data to the server with ajax, but there are situations where I also want to send a Javascript object data back to the server on postbacks. So I guess it needs to be in a hidden field.
A couple general questions about this.
1) What is the best way to do this in terms of minimizing complexity and optimizing space and efficiency? In researching this I discovered Protocol Buffers but there does not seem to be a good C# implementation. I did find one, but it was a couple years old and self-described as buggy so that scared me.
2) If I just pass a JSON string, how can I be sure it will be safe to include as the value for a hidden field? Is there any reason I might not want to do this? I could Base64 encode, but it seems like this adds a lot of overhead. What is considered the best or preferred method?
298
In the past, I've usually done the following:
So I'm not sure what you're trying to gain through encoding, but I think the expense of transforming the object from JSON (or XML) to something smaller is too much overhead for any packaging/shrinking benefit. (Unless your a super high traffic site concerned more about bandwidth usage than server/client side processing.)
EXAMPLE
Hopefully this gives you an idea of how to accomplish this. Let me know if you have any more questions.
<html>
<head>
</head>
<body>
<input type="button" id="btnObject" value="Show Object" />
<input type="button" id="btnShowHid" value="Show Hidden Input Value" />
<input type="hidden" id="hidInput" value="" />
</body>
</html>
<script type='text/javascript' src='https://ajax.googleapis.com/ajax/libs/jquery/1.5.0/jquery.min.js'></script>
<script type='text/javascript' src='https://github.com/douglascrockford/JSON-js/raw/master/json2.js'></script>
<script>
//Your JSON Object
var myJSONObject = {"bindings": [
{"ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*"},
{"ircEvent": "PRIVMSG", "method": "deleteURI", "regex": "^delete.*"},
{"ircEvent": "PRIVMSG", "method": "randomURI", "regex": "^random.*"}
]
};
//jQuery Document Ready Event
$(function(){
//Get a reference to your hidden field
var $hidInput = $("#hidInput");
//Use json2.js library to convert the json object to a string
//and assign it to the hidden input's value
//NOTE: ASP.NET hidden input control reduces to a hidden input so you can treat them the same.
$hidInput.val(JSON.stringify(myJSONObject));
//Set up click events to view object and hidden value
$("#btnShowHid").click(function(){
alert($hidInput.val());
});
$("#btnObject").click(function(){
alert(myJSONObject);
});
});
</script>
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