Can i store a Queue in viewstate? only will store the first item i add to queue
- by Mausimo
Hey, as the question states i am trying to store a Queue in a viewstate (to track postbacks and refreshes to stop a form from resubmitting).
Here is just the viewstate code:
private Queue<string> p_tempQue
{
set
{
ViewState["sTemp"] = value;
}
get
{
return (Queue<string>)ViewState["sTemp"];
}
}
//BasePage constructor
public BasePage()
{
//create a Queue of string
//sTemp = new Queue();
this.Load += new EventHandler(this.Page_Load);
this.Init += new EventHandler(this.Page_Init);
}
//In the 'page_Init' event we have created a simple hidden field by name 'hdnGuid' which is attached to the page on the first hit itself.
protected void Page_Init(object sender, EventArgs e)
{
//initializing the hidden field
//create a hidden field with a ID
HiddenField hdnGuid = new HiddenField();
hdnGuid.ID = "hdnGuid";
//if it is the first time the page is loaded, create a new guid and assign it as the hidden field value
if (!Page.IsPostBack)
hdnGuid.Value = Guid.NewGuid().ToString();
//add the hidden field to the page
Page.Form.Controls.Add(hdnGuid);
}
//In the 'page_Load' event we check if the hidden field value is same as the old value. In case the value is not same that means it's a 'postback'
//and if the value is same then its 'refresh'. As per situation we set the 'httpContent.Items["Refresh"]' value.
protected void Page_Load(object sender, EventArgs e)
{
if(p_tempQue != null)
sTemp = p_tempQue;
else
sTemp = new Queue<string>();
//The hdnGuid will be set the first time page is loaded, else the hdnGuid
//will be set after each time the form is submitted using javascript.
//assign the hidden field currently on the page for manipulation
HiddenField h1 = (HiddenField)(Page.Form.FindControl("hdnGuid"));
//create an instance of the GuidClass
GuidClass currentGuid = new GuidClass();
//set the GuidClass Guid property to the value of the hidden field
currentGuid.Guid = h1.Value;
//check to see if the Queue of strings contains the string which is the current Guid property of the GuidClass
//if the are equal, then the page was refreshed
if (sTemp.Contains<string>(currentGuid.Guid))
{
//adds item as key/value pair to share data between an System.Web.IHttpModule interface and an System.Web.IHttpHandler interface during an HTTP request.
System.Web.HttpContext.Current.Items.Add("IsRefresh", true);
}
//if they are not requal, the page is not refreshed
else
{
//if the current Guid property in the GuidClass is not null or not an empty string
//add the new Guid to the Queue
if (!(currentGuid.Guid.Equals(null) || currentGuid.Guid.Equals("")))
sTemp.Enqueue(currentGuid.Guid);
System.Web.HttpContext.Current.Items.Add("IsRefresh", false);
}
p_tempQue = sTemp;
}
