How to use Json to replace viewstate using in GridView

Dear All:

My project is winform, and I recently hope to use json.net to replace the viewstate using in gridview, like following:

[Serializable]
public class MyDataForm
{
	public string LocationCode { get; set; }
	public string ProjectNo { get; set; }
	public string PatientName { get; set; }
	public string PersonID { get; set; }
	public string PdfURL { get; set; }
	public string Memos { get; set; }
}

public List<MyDataForm> MyDataList { set { ViewState["MyDataList"] = value; } get { return ViewState["MyDataList"] as List<MyDataForm>; } }

protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
	GridView1.EditIndex = -1;
	GridView1.PageIndex = e.NewPageIndex;
	GridView1.DataSource = MyDataList;
	GridView1.DataBind();
}

I hope to store the data in HiddenField, and then  catch the data back via JsonConvert.DeserializeObject<MyDataForm>( $("#hiddenFieldID").val()) when post back each time. 

The main problem is come from when to replace viewstate in ASP life cycle. 

In which stage, like Page_init, the gridview will call databind(), and if I can put the data which deserialize by Json in datasource, 

And then I think it can replace viewstate completely, is anyone know how to make that, thanks a lot.