Serialize and Deserialize to JSON from ASP.NET

mac2022-06-30 26

Its very easy to serialize an object to .NETSimply create some object, normally a custom class with some attributes.Normally you have a list of these and you want to serialize to JSON to use it from client side code.

If you do the following

var s = new System.Web.Script.Serialization.JavaScriptSerializer(); string resultJs = s.Serialize(result);

you will end up with a JSON array that you were looking for:

[ { "Desc" : "Corn 100 ", "ItemNo" : "123456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.21 } , { "Desc" : "Ice 100 ", "ItemNo" : "323456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.50 } , { "Desc" : "Meat 100 ", "ItemNo" : "423456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.11 } ]

However if you try to deserialize this back into an object by running

var json = new System.Web.Script.Serialization.JavaScriptSerializer(); var result = json.Deserialize<ShoppingCartItem[]>(jsonItemArray);

You will get a NULL type Exception.

The solution is to create a simple resolver as follows

using System; using System.Web; using System.Web.Compilation; using System.Web.Script.Serialization; namespace XYZ.Util { /// <summary> /// as __type is missing ,we need to add this /// </summary> public class ManualResolver : SimpleTypeResolver { public ManualResolver() { } public override Type ResolveType(string id) { return System.Web.Compilation.BuildManager.GetType(id, false); } } }

2) Use it to serialize

var s = new System.Web.Script.Serialization.JavaScriptSerializer(new XYZ.Util.ManualResolver()); string resultJs = s.Serialize(result); lblJs.Text = string.Format("<script>var resultObj = {0};</script>", resultJs);

You will get something like the following this time (note new __type included this time)

[ { "__type":"XYZ.Data.Entities.ShoppingCartItem, XYZ.Data, Version=1.7.1.0, Culture=neutral, PublicKeyToken=null", "Desc" : "Corn 100 ", "ItemNo" : "123456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.21 } , { "__type":"XYZ.Data.Entities.ShoppingCartItem, XYZ.Data, Version=1.7.1.0, Culture=neutral, PublicKeyToken=null", "Desc" : "Ice 100 ", "ItemNo" : "323456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.50 } , { "__type":"XYZ.Data.Entities.ShoppingCartItem, XYZ.Data, Version=1.7.1.0, Culture=neutral, PublicKeyToken=null", "Desc" : "Meat 100 ", "ItemNo" : "423456", "OriginalQty" : 50, "Qty" : 50, "UnitPrice" : 10.11 } ]

3) Use it to deserialize

System.Web.Script.Serialization.JavaScriptSerializer(new XYZ.Util.ManualResolver()); var result = json.Deserialize<ShoppingCartItem[]>(jsonItemArray);

References: Comment by Manuel Abadia on ASP.NET AJAX Extensions Internals – Web Service Proxy Generation

Serialize and Deserialize to JSON from ASP.NET

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