/// <summary>
/// Registers current page in navigation history so that user can come back to it later.
/// Put it in Page_Load event in "if(!PostBack)" structure in every page that participates in navigation functionality (that uses Navigation class).
/// </summary>
/// <param name="pageName">Name of current page in form PageName.aspx</param>
public static void RegisterPage(string pageName)
{
NavigationHistoryItem newItem = new NavigationHistoryItem();
newItem.pageName = pageName;
newItem.queryString = HttpContext.Current.Request.QueryString;
Navigation.history.Push(newItem);
Navigation.UpdateHistory();
}
/// <summary>
/// Redirects back to previous page that exist in navigation history stack structure.
/// (For example if history is A->B->C and current page is C it redirects to B page)
/// To return to page it needs to be registered (see Navigation.RegisterPage method).
/// </summary>
/// <param name="useStoredQueryString">Append (to Url) query string that existed at time the page was registered?</param>
/// <param name="queryStringToAppend">Optionaly add key/value pairs in form: A=B ampersand C=D ampersand E=F. Do not include question mark nor spaces.</param>
public static void GoBack(bool useStoredQueryString, string queryStringToAppend)
{
if (Navigation.history.Count > 0)
{
//Release current page history item
Navigation.history.Pop();
Navigation.UpdateHistory();
}
if (Navigation.history.Count == 0)
{
throw new Exception("Navigation history is empty. Can not go back.");
}
else
{
//Get previous page history item
NavigationHistoryItem previousItem = Navigation.history.Pop();
Navigation.UpdateHistory();
//TODO: If key from queryStringToAppend exist in stored query string also it should replace that key in stored query string
//Build query string
string queryString = "";
if (useStoredQueryString)
{
queryString = BuildQueryString(previousItem.queryString);
}
if (queryStringToAppend != null && queryStringToAppend != string.Empty)
{
queryString += ((queryString != string.Empty) ? "&" : "") + queryStringToAppend;
}
queryString = Navigation.AddQuestionMarkIfNotEmpty(queryString);
//Go back using history item
HttpContext.Current.Response.Redirect(
Navigation.GetApplicationRootUrl()
+ "/"
+ previousItem.pageName
+ queryString
);
}
}
