HTML:

<div class="row">            
	<div class="col-12">
		<label>類別代碼:</label>
		<input id="txt_gcode" type="text" class="form-text" />
	</div>
</div>
<div class="row">
	<div class="col-12">
		<label>類別名稱:</label>
		<input id="txt_gname" type="text" class="form-text" />
	</div>
</div>
<div class="row">
	<div class="col-12">
		<hr />                
		<button id="btn_send2" class="btn btn-danger" type="button" onclick="stringify()">新增</button>
	</div>
</div>


Javascript:

function stringify() {
	let obj = new Object();            
	obj.gcode = $("#txt_gcode").val();
	obj.gname = $("#txt_gname").val();

	let array = [];
	array.push(obj);

	$.ajax({
		type: "POST",
		url: "ashx/testJson.ashx",
		data: JSON.stringify(array),
		success: function (e) {
			readData();
			alert(e);
		}
	});

	/*alert(JSON.stringify(array));*/
}


testJson.ashx:

scratchDataContext sdc = new scratchDataContext();
static List<gc> _tj = new List<gc>();

public void ProcessRequest(HttpContext context)
{
	string json = string.Empty;

	//讀取前端傳來的 json 字串
	using (var reader = new System.IO.StreamReader(context.Request.InputStream))
	{
		json = reader.ReadToEnd();
	}

	//將json 字串轉換成物件
	if (!string.IsNullOrEmpty(json))
	{
		_tj = JsonConvert.DeserializeObject<List<gc>>(json);
	}

	gameClass gclass = new gameClass();
	gclass.g_code = _tj.FirstOrDefault().gcode;
	gclass.g_name = _tj.FirstOrDefault().gname;

	sdc.gameClass.InsertOnSubmit(gclass);
	sdc.SubmitChanges();

	context.Response.ContentType = "text/plain";
	context.Response.Write("成功新增一個項目");
}

public bool IsReusable
{
	get
	{
		return false;
	}
}

public class gc
{
	public string gcode;
	public string gname;
}