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C# web forms - How to pass data from master page to master page when redirect is on web form?

When on master page I have dropDownList with event. When event Raise I want to load/redirect webForm.aspx. In this webForm.aspx I want to load data based on dropDownList selected item. At the same time I want to load again dropDownList and select Item on which clicked was.
I created some solution, where I was using Response.Redirect("webform.aspx?courseID=4") on masterPage.
Is this good approach to this problem? I think there must be better, but I cant see it.
Thanks for answers.

One way is your solution: to use querystring.
The second way is: on dropdownlist's value changing you changing value of some session value (e.g. *Session["course_id"]), then Response.Redirect("webform.aspx") and restore by Session["course_id"] value.
protected void ddlCourses_SelectedIndexChanged(object sender, EventArgs e){
Session["course_id"] = ddlCourses.SelectedValue;
Response.Redirect("webform.aspx");
}
ABOUT YOUR SECOND QUESTION (HOW TO TAKE ROUTE VALUE FROM MASTER PAGE). I will give just brief explanation and a little example.
Create in your master page some method:
protected void IWantToWarkWithRouteValue(){
//here you will do something
//and to take value from routing, just use Session["myValue"] (I will explain this value later)
}
You should call this method in Page_Load, not in Pre_Init or Init
Then in your Course.aspx (caz' you using routing here) create the next method:
protected void SetCourseSessionFromTheRoute(){
if (Page.RouteData.Values["courseID"] != null)
Session["myValue"] = Page.RouteData.Values["courseID"].ToString();
}
And call this method in Page_PreInit:
protected void Page_PreInit(object sender, EventArgs e){
SetCourseSessionFromTheRoute();
}
Thanksgiving to ASP.NET page's life cycle, you may do anything you need.
You may read about page's lifecycle here
As I said, it is just an example. You may find a better solution.
Hope it helps.

Event before redirect to another page

I've just developed a new GridView MultiFilter control ( CompositeControl ) that works like the image below:
I use ViewState for my control's properties so it keeps all values after postback. I want to save my control properties to a Session before redirect so I can load properties back to my control when my page loads again.
Does anyone have any suggestions about how this can be accomplished?

You have to do 2 things in this list page:
(1)Page load
(2)Search click
And 1 thing in detail (redirected) page:
(3)Pass some query string while back to list page
(1)while page load decide to load normal or searched (back from detail page) data
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Request.QueryString["back"] != null)
bindDataFirst();
// same data load logic as present
else
bindDataForBack();
// you come back from detail page hence bind search & grid data
}
private void bindDataForBack()
{
strName = Session["SearchName"] == null ? "" : Session["SearchName"].ToString();
// check session search conditions & data and bind
//also bind grid by respective search parameters & search options (top side)
(2)search click store search data into session
public void btnSearch_Click(object sender, System.EventArgs e)
{
Session["SearchName"] = strName;// store search data into session variables
//bind grid by respective search parameters
(3)in redirected (detail) page set back button like:
public void btnBack_Click(object sender, System.EventArgs e)
{
Response.Redirect("ListPage.aspx?back=1");
I hope this may helps you. I suggest to implement this with one textbox & grid and then try with your present scenario.
Please mark this answer useful if this solve your problem.

You can assign data to Session the pretty much the same way you assign to ViewState.
It's a key value dictionary just like ViewState.
Ex:
Session["someKey"] = "An arbitrary value";

If you can redirect to another page using form submit then You can post your form to the required page using action attribute of your page. This way values of all controls will be available in the Request["KEY NAME HERE"]
<form action="anotherpage.aspx" id="frmData">
<!-- YOUR CONTROLS HERE -->
<input type="submit" value="Submit" />
</fomr>
you can also submit your form using JS
$("#frmData").submit();

UpdatePanel.Update() command generates a full Page_load

I have a Update Panel inside a User Control i use on 2 pages in my website
Both pages use the same MasterPage, ScriptManger is declared in the MasterPage.
Both pages call the UC the same way:
<uc:SearchCube runat="server" ID="searchCube" />
in the Update panel i have many RadioButtons that on change generate a server side event that fill dropdown in the update panel and update the panel
protected void SearchCategoryChanged(object sender, EventArgs e)
{
FillDropdowns();
SearchOptions.Update();
}
Update Panel is set like this:
<asp:UpdatePanel ID="SearchOptions" runat="server" UpdateMode="Conditional"
hildrenAsTriggers="true"/>
Each RadioButton is set like this:
<asp:RadioButton ID="RadioButton1" GroupName="SearchCategory" runat="server"
AutoPostBack="true" OnCheckedChanged="SearchCategoryChanged" Text="Text"/>
I also have an AsyncPostBackTrigger on each Radio Button Controller
The problem i have is that on one page when i call the Update() function the panel is updated and Page_Load is triggered which causes the UC to refresh and reload the default settings of the UC
I can see in DEBUG mode that on the working page Update() does not generate Page_Load.
Can anyone explain to me why this is happening?

Everytime a request goes to the server, it executes the Page_Load event.
What you need to do is make sure you have a PostBack validation on all your pages:
protectec void Page_Load(object sender, EventArgs e)
{
if(!Page.IsPostBack)
{
//Not a postBack: Normal page load
//Init your page here
}
else
{
//It's a PostBack (from a command).
//Do nothing or init stuff your all your commands.
}
}
If you put some breakpoints in your Page Load and your SearchCategoryChanged method, you'll be able to see what the pipeline looks like.

Fixed my problem.
the problematic page is an index page that takes a few parameters in.
I have a Response.Redirect() on the page to avoid duplication of pages.
Apparently when the PostBack() is made it calls the page without any parameters and i was forcing it to be redirected into a default view since no parameters were sent to the page.
i found a lead to my problem in a Microsoft help forum that stated:
By calling Response.Write() directly you are bypassing the normal
rendering mechanism of ASP.NET controls. The bits you write are going
straight out to the client without further processing (well,
mostly...). This means that UpdatePanel can't encode the data in its
special format.
Anyway the page was reloading every time which caused it to reload the User Control with it's default values.

set focus on the first textbox on the page with ajax editor in .net

I a have a web form with few textboxes,dropdowns and finally towards the end of the page is 4 custom ajax editors. So on page load the focus is always inside the last editor and no way it comes to the first text box or top of page.On each page load the cursor goes inside the last editor control.How to bring the focus inside the first text box?
Below are the few methods i tried
1.<body onload="document.body.scrollTop = 0;">
2. void Page_Init(object sender, EventArgs e)
{
SetFocus(txtReqtitle);
}
for the above while loading the page i could see the focus goes to the desired text box and then it comes to the last custom control.
3. if(!Page.ClientScript.IsStartupScriptRegistered("scrFocus"))
{
string strScript="var txtBox=document.getElementById('" + txtReqtitle.ClientID.ToString() +"');txtBox.focus();";
ClientScript.RegisterStartupScript(this.GetType(),"scrFocus", strScript,true);
}
4.
function setFocus() {
document.getElementById("txtReqtitle").focus();
}
5. ScriptManager.GetCurrent(this.Page).SetFocus(txtReqtitle);
Any ideas? Thanks..

Seems focus property is not working in load event because of ajax editors
Please add txtReqtitle.Focus() in Page Prerendercomplete() event and let me know whether it works

found the solution which worked for me .would like to share it .. its simple ..just make the autofocus=false for the control.

using jquery
$(document).ready(function(){
$('#<%= txtReqtitle.ClientID %>').focus();
});

What is the effect of IsPostBack Condition?

I have a aspx Page where I am using AJAX. like
<asp:UpdatePanel runat="server" ID="upPanelDDLProgram">
<ContentTemplate>
<asp:DropDownList ID="DDLProgram" runat="server" Width="194px" Height="18px" OnSelectedIndexChanged="OnDDLProgramChanged" AutoPostBack="true">
</asp:DropDownList>
</ContentTemplate>
</asp:UpdatePanel>
and my code behind is like
protected void Page_Load(object sender, EventArgs e)
{
//if (!IsPostBack)
//{
// BindProgramDDL();
//}
BindProgramDDL();
}
protected void BindProgramDDL()
{
List<CcProgramEntity> programEntities = FormSaleSubmit_BAO.GetAllPrograms();
DDLProgram.DataSource = programEntities;
DDLProgram.DataTextField = "Shortname";
DDLProgram.DataValueField = "Id";
DDLProgram.DataBind();
string programCode = programEntities[DDLProgram.SelectedIndex].Code;
}
protected void OnDDLProgramChanged(object sender, EventArgs e)
{
List<CcProgramEntity> programEntities = FormSaleSubmit_BAO.GetAllPrograms();
string programCode = programEntities[DDLProgram.SelectedIndex].Code;
}
the If condition is the page load event, is commented out. If I toggle the comment part of the page load event, it works perfect in both cases. My question is why is this heppening?

IsPostBack tells you if it is a second request to the page. The benefit here is if you need to do anything costly, such as a database call to fill a dropdownlist or similar, you can do it when !IsPostback, then use ViewState to retain the values.
To put it specific to your situation
Using:
if (!IsPostBack)
{
BindProgramDDL();
}
Will result in BindProgramDDL being called ONLY on the first time the page is loaded, all AJAX or other user interaction with the page will NOT call BindProgramDDL;
Without that, in place EVERY page load would call the method, un-necessarily hitting the database for the records.

If I am getting you correct .......
DropDown list has data even you are not binding it second time after post back..........its becasuse its server side control and each serverside control has its view state with it thats y its not removing data.
IsPostBack - it true when do the post back by using serverside control like dropdown, checkbox , textbox............When you load page first time this property is false but in subsequent request to same page value of this property is true. you can check msdn document for more detail about it.

It's basically saying are you visiting the page for the first time (not a post back), or has the user clicked on a control (a post back).
Useful for when you only want to run methods once when the page is initially loaded
You're code should probably look like this to achieve best results
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindProgramDDL();
}
}

I suspect that the DropDownList saves the items in the ViewState and then work with them during all subsequesnt requests. That is why your code works even if the editor's DataSource is set only when IsPostBack returns false.

PostBack event appears on every action (ajax too), except of first page load.

Page.IsPostBack
indicates whether the page is being rendered for the first time or is being loaded in response to a postback.
see http://msdn.microsoft.com/en-us/library/system.web.ui.page.ispostback.aspx
Since you've bound your datasource the first time the page was loaded, the data are still in the viewstate and you don't need to update the control (unless the datasource has changed).
Take also into account that, since you're using ajax, you may also want to intercept if there was an 'asynchronous postback'.
See http://encosia.com/are-you-making-these-3-common-aspnet-ajax-mistakes/