Here is what I am trying to do. I have a TreeView server side control (asp.net 2.0) and I need the user to be able to add nodes to it, then after all the nodes desired are added, the data should be saved to the database.
Here are some things I would like to pay attention to:
1) I don't want to save the tree data each time the new node is added, but rather keep the data in session until the user decides to save the entire tree. The question here is: can I bind the tree to ArrayList object and keep that object in session (rather than keeping the whole tree in session)? Then each time the node is added I will have to rebind the tree to the ArrayList rather than database.
2) I wish to minimize ViewState, any tips? What works best: compressing viewstate or keeping it all on the server at all times?
Thanks!
Use TreeNodeCollection as your internal array to hold in either ViewState or Session. Here's a rough mock-up of an approach you can use; far from perfect, but should set you on the right track.
TreeView tv = new TreeView();
// Button click event for 'Add Node' button
protected void AddNode(object sender, EventArgs e)
{
if (SaveNodeToDb(txtNewNode.Text, txtNavUrl.Text))
{
// Store user input details for new node in Session
Nodes.Add(new TreeNode() { Text = txtNewNode.Text, NavigateUrl = txtNavUrl.Text });
// Clear and re-add
tv.Nodes.Clear();
foreach (TreeNode n in Nodes)
tv.Nodes.Add(n);
}
}
public bool SaveNodeToDb(string name, string url)
{
// DB save action here.
}
public TreeNodeCollection Nodes
{
get
{
if (Session["UserNodes"] ! = null)
return (TreeNodeCollection) Session["UserNodes"];
else
return new TreeNodeCollection();
}
set
{
Session["UserNodes"] = value;
}
}
Related
Edit (more brief):
I have a control "configuration" with a tree view on the left and a list of panels on the right to which i add my controls. These elements are placed inside a table and surrounded by an ajax panel.
Let's say i have a tree node cars with two elements car1 and car2. When i click an item i save the ID and Type of the selected tree node inside hidden fields to be able to load the right user control on Page_Init
protected void Page_Init(object sender, EventArgs e)
{
var type = this.Request.Form["ctl00$MainContent$ctl00$typeId"];
var id = this.Request.Form["ctl00$MainContent$ctl00$entityId"];
if (!string.IsNullOrEmpty(type) && !string.IsNullOrEmpty(id))
{
this.LoadUserControl(type, id);
}
}
private void LoadUserControl(string type, string id)
{
if (Convert.ToInt32(type) != 0)
{
switch (Convert.ToInt32(type))
{
case (int)SkTopics.Product:
this.AddUserControl("../Modules/Product.ascx", this.Product, type, id);
break;
}
}
}
private void AddUserControl(string controlName, Panel panel, string type, string id)
{
// Init new user cotntrol
control = (BaseControl)this.LoadControl(controlName);
control.LoadEntityItem(Convert.ToInt32(id));
// Setting the user control ID
var replace = controlName.Replace("../Modules/", string.Empty);
string userControlId = replace.Split('.')[0] + id;
var targetControl = panel.FindControl(userControlId);
if (object.Equals(targetControl, null))
{
control.ID = userControlId;
control.DataBind();
panel.Controls.Add(control);
}
}
On LoadEntityItem the data for this car are collected from the database and the values are set as Text of textboxes. When i now switch to the second car, the new values are displayed.
Problem: I change the values inside the textboxes and press the save button to call my save method of the user control. From now on, when i switch to the car 1 again, the values for car 2 are still displayed, although the data for car1 are filled. tO see the data for car1 i have to switch to a complete different type of control and then back to the car1.
Another problem is, that i have a binary image inside the user control which Data i fill on init. When i swith to the the next car, where there i no image configured, i set the image data to null, but the image from the previous car i show. Onyl if i set a different image data the new image is displayed.
There is something else i noticed:
Inside the user control i call a javascript funtion but this one is only called on clicking the the save button. It seems that there is a different between the switch of the tree node and the save button click ?
ScriptManager.RegisterStartupScript(this, this.GetType(), "InitScrewPointsForDragging", "InitScrewPointsForDragging();", true);
I hope this was more brief than before.
It seems that the reason for the issue is some improper viewstate handling and after I disable the view state it is working correctly at my side. Here is the code that I updated to have it work at my side:
this.control.EnableViewState = false;
this.control.ID = userControlId;
I am having user control registered on a aspx page.
there is a button on user control resisted on some aspx page that perform some action to store the value of viewste to the database, and below that i have cleared my viewstate value, but if i do right click and reload the page it reinsert the values to the data base, what i am missing or the viewstate do not get cleared, how should i prevent it to resave the same entries to the database.
I am partially writing my code below.
protected void btnFinish_Click(object sender, EventArgs e)
{
if (ViewState["dtQuestions"] != null)
{
foreach (DataRow dr in dtQuestions.Rows)
{
int currQueScore = GetAnswerScore(dr["AnswerType"].ToString().Trim(), dr["ClientAnswerValue"].ToString().Trim());
dr["ClientAnswerScore"] = currQueScore;
myScore += currQueScore;
SurveyClientAnswer objDetail = new SurveyClientAnswer();
objDetail.SurveyClientID = objMaster.SurveyClientID;
objDetail.QuestionID = int.Parse(dr["QuestionID"].ToString());
objDetail.Answer = dr["ClientAnswerValue"].ToString();
objDetail.Score = int.Parse(dr["ClientAnswerScore"].ToString());
DB.SurveyClientAnswers.InsertOnSubmit(objDetail);
DB.SubmitChanges();
}
objMaster.FinalScore = myScore;
DB.SubmitChanges();
ViewState["dtQuestions"] = null;
}
else
{
ModalPopupExtender1.Show();
pnl.Visible = true;
}
}
If you don't want to reinsert the data, simply create a unique constraint on the database to disallow this scenario.
As far as doing it in code, you could possibly only insert the data adding this condition to the if statement:
if(IsPostBack && (ViewState["dtQuestions"] != null)
{
//meaning the user is not simply reloading the page but actually posting back
}
Note that there might be some corner cases where this won't work. Without testing is difficult to know but I strongly believe that this should be handled at the database level instead.
I have a GridView on ASP.NET web form which I have bound to a data source and set it to have 10 records per page.
I also have a hyper link column on the GridView, such that a user can navigate to another page (details page) from the list. On the details page, they have "Back" button to return to the GridView page
Edit
Just to clarify the query
I am looking for sample code snippet on the Server Side on how to specify the page index to set the GridView after data binding. The idea is to ensure the user navigates to the same page index they were on.
The three basic options at your disposal: query string, session, cookie. They each have their drawbacks and pluses:
Using the query string will require you to format all links leading to the page with the gridview to have the proper information in the query string (which could end up being more than just a page number).
Using a session would work if you're sure that each browser instance will want to go to the same gridview, otherwise you'll have to tag your session variable with some id key that is uniquely identifiable to each gridview page in question. This could result in the session management of a lot of variables that may be completely undesirable as most of them will have to expire by timeout only.
Using a cookie would require something similar where cookie data is stored in a key/data matrix (optimized hash table might work for this). It would not be recommended to have a separate cookie name for each gridview page you're tracking, but rather have a cookie with a common name that holds the data for all gridview pages being tracked and inside that have the key/value structure.
Edit: A small code snippet on setting the page index.
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
try
{
if(HttpContext.Current.Request["myGVPageId"] != null])
{
myGridview.PageIndex = Convert.ToInt32(HttpContext.Current.Request["myGVPageId"]);
}
}
catch(Exception ex)
{
// log it
}
}
}
I'm more of a fan of the Session approach, personally. Simply save your page index as a session variable, and, if this Session variable isn't null on page load, use it to fire your "OnPageIndexChanging" method, like so:
Set your current page number whenever the page number changes:
protected void GridViewIndexChanging(object sender, GridViewPageEventArgs e)
{
myGridView.PageIndex = e.NewPageIndex;
Session["pageNumber"] = e.NewPageIndex;
//whatever your page index changing does...
}
Then, on Page_Load do something like:
if (!IsPostBack)
{
if (Session["pageNumber"] != null)
{
GridViewIndexChanged(myGridView, new GridViewPageEventArgs((int)Session["pageNumber"]));
}
}
you can ues the Page Index Change Event of Gridview and Find out the Current Page Index for e:g
yourGridId.PageIndex=e.NewPageIndex;
ViewState["GridPageIndex"]=e.NewPageIndex;
on PageLoad Get the Viewstate Value
string pIndex=string.Empty;
pIndex=Convert.toInt32(ViewState["GridPageIndex"]);
if(!string.Empty(pIndex))
{
yourGridId.PageIndex =pIndex;
}
you must use query string and is recommended, otherwise you can use session object but don't use that for this as you may have grid view opening in different pages so use query string .
gridView1.CurrentPageIndex = (Request["pageNo"] != null) ? Request["pageNo"] as int : 0;
gridView1.DataSource = myDataSet;
gridView1.DataBind();
you can update your link on GridView_DataBound event
I have some problem that happens when controls are loaded in init and it still doesn't help me to get proper postback event fired on time.
I am trying to create a rich wizard control that will enable switching, links with description, completely customized steps, integration of substeps - by using dynamic control load that is avoids standard asp.net wizard way of loading.
Idea is to have on left part navigation, on right part content, or substeps that are run from right part and that go over whole area.
Download source project
Ok, I re-read the question, and here is what you have to do. You have to re-load these controls on each postback, give them always the same "Id". This can be done in Page_Init or in Page_Load event. And of course, you have to re-attach event handlers on each post back.
Many thanks.. well i found the answer - id was the problem, in load control method. I was doing this wizard.. well most of things work now.
If someone is interested to see how does this works.. there are some updates:
public void LoadSplitViewControl(string path)
{
SwitchNavigationView(NavigationView.SplitView);
LastNavigationView = NavigationView.SplitView;
LoadControl(SplitControlLoader, path, "LoadedControlSplit");
}
public void LoadSingleViewControl(string path)
{
SwitchNavigationView(NavigationView.SingleView);
LastNavigationView = NavigationView.SingleView;
LoadControl(SingleControlLoader, path, "LoadedControlSingle");
}
public void LoadSingleViewControlAsClear(string path)
{
SwitchNavigationView(NavigationView.SingleView);
LastNavigationView = NavigationView.SingleView;
LoadControlAsClear(SingleControlLoader, path, "LoadedControlSingle");
}
private void LoadControl(PlaceHolder holder, string path, string ID)
{
UserControl ctrl = (UserControl)Page.LoadControl(path);
ctrl.ID = ID;
LastControlPath = path;
holder.Controls.Clear();
holder.Controls.Add(ctrl);
}
//as i am using steps loaded controls using splitview and substeps controls using single view sometimes viewstate will not be valid so error will be thrown but u can resolve this by using LoadSingleViewControlAsClear that will load below method.
private void LoadControlAsClear(PlaceHolder holder, string path, string ID)
{
UserControl ctrl = (UserControl)Page.LoadControl(path);
ctrl.ID = ID;
LastControlPath = path;
ctrl.EnableViewState = false;
holder.Controls.Add(ctrl);
}
/another cool idea i am using for such an wizard is that i am not using viewstate but rather session object for saving values collected over steps. My session object key is generated by authenticated username and pageguid - so u can have many loaded pages and each of them will handle different session object./
public Guid PageGuid
{
get
{
if (PageGuidField.Value == "")
{
var _pageGuid = Guid.NewGuid();
PageGuidField.Value = _pageGuid.ToString();
return _pageGuid;
}
return new Guid(PageGuidField.Value);
}
}
Ive no problems using Javascript to read the rows of a telerik radgrid component im using however I can seem to find anyway to access the row data server side when a postback occurs. Ive spent ages looking for solution but no luck.
Any pointers would be greatly appreciated.
Tony
You might want to look at the DataKeyValues property of the OwnerTableView object, which will let you access a collection of values that represent the fields in a given row. I use it during the EditCommand event handler, since a user of my site is directed to an edit page if they click on the link to edit a row in the grid, and I need to pass along certain info about the given row in the query string.
If this turns out to be what you need, you'll also need to define which fields should be made available through this property. To do that, look at the MasterTableView.DataKeyNames property in the property sheet for the grid. You basically specify a comma-delimited list of field names.
The server-side is the easy part:
GridItemCollection gridRows = TestGrid.Items;
foreach (GridDataItem data in gridRows)
{
ItemClass obj = (ItemClass)data.DataItem;
}
It's the client side part that I don't know! :[
private Int32 GetID()
{
foreach (Telerik.Web.UI.GridDataItem dataItem in radGrid.MasterTableView.Items)
{
if (dataItem.Selected == true)
{
Int32 ID = (Int32)dataItem.GetDataKeyValue("ID");
return ID;
}
}
throw new ArgumentNullException("Id Not found");
}
This is the one that works for me and uses the RadGrid.SelectedItems collection.
protected void LinkButton1_Click(object sender, EventArgs e)
{
List<Guid> OrderIdList = new List<Guid>();
foreach (GridDataItem OrderItem in this.RadGrid1.SelectedItems)
{
OrderIdList.Add(new Guid(OrderItem.GetDataKeyValue("OrderId").ToString()));
}
}
If you correctly created your controls in markup or page init for dynamic controls, then the RadGrid will properly restore state.
You can access the initial values that were loaded from the data source like this example below, provided you told the table view in question to keep the columns around in the data keys.
protected T GetInitialGridData<T>(GridDataItem item, string uniqueColumnName) {
item.ThrowIfNull("item");
uniqueColumnName.ThrowIfNullOrEmpty("uniqueColumnName");
return (T)item.OwnerTableView.DataKeyValues(gridItem.ItemIndex)(columnName);
}
If you are using a dynamic custom template column, and need to get to any values that may now be in their states, you can use:
protected string GetCustomTextBoxValue(GridDataItem item, string controlID) {
item.ThrowIfNull("item");
controlID.ThrowIfNullOrTrimmedEmpty("controlID");
return ((TextBox)item.FindControl(controlID)).Text;
}
private Int32 GetID()
{
foreach (Telerik.Web.UI.GridDataItem dataItem in radGrid.MasterTableView.Items)
{
if (dataItem.Selected == true)
{
// Int32 ID = (Int32)dataItem.GetDataKeyValue("ID");
Int32 ID =Convert.ToInt32(dataItem.GetDataKeyValue("ID"));
return ID;
}
}
}
//this will work