I am using different user controls with Modalpopupextender (within page, repeater etc.) and it took some time to figure all the tricks how to get this two togeather.
I have now ended up with the following problem
When I pass a param into user control
UserControl.ParamID = 1;
I am able to receive it in user control, but at the strange step of page cycle.
When I try to do
protected void Page_PreRender(object sender, EventArgs e)
{
throw new Exception(ParamID);
}
I get null for ParamID!?
But when I do
<% throw new Exception(ParamID); %>
from html, I get a correct ParamID value.
I tryied to store ParamID as ViewState, as a HiddeField, and it is always doing the same error.
Also, when I use this user control wihout mpe, just in regular aspx page, it all works just fine.
What is the catch?
Related
I have 5 dropdownlist in asp.net.User selects 5 dropdownlist after that click to button.Button sends page to another page.If i go previous page dropdownlist selectedvalues and datas lose(it displays default values without selected values)
I tried below
Response.Redirect("PreviousPage.aspx");
datas losing is there any solution ?
Instead of using Response.Redirect(), you can change the PostBackUrl of the button to the target page, or use Server.Transfer(). Once there you should be able to access the properties you need from the Page.PreviousPage object.
Example using Server.Transfer:
Page1.aspx.cs:
protected void SubmitButton_Click(object sender, EventArgs e)
{
Server.Transfer("Page2.aspx");
}
Page2.aspx.cs:
protected void Page_Load(object sender, EventArgs e)
{
var addressDropdownSelectedValue = ((Page1)Page).PreviousPage.AddressDropdown.SelectedItem.Value; //or SelectedValue
}
With the ScriptManager in the AJAX control toolkit (you get this in 4.0+, I think maybe even in 3.5), you can add history points. You add a history point and use that value to rebuild the page state.
http://msdn.microsoft.com/en-us/library/cc488548%28v=vs.140%29.aspx
You can also strongly type the previous page if you want to grab values from it. You do this with <%# PreviousPage %> directive. Then in code you could use Page.PreviousPage.FindControl
I have in Site.Master:
<% if(Session["msg"]!=null) Response.Write(Session["msg"].ToString()); %>
I have also on submit form method:
protected void Send_Click(object sender, EventArgs e)
{
Session["msg"] = "Thx for email.";
Response.Redirect("~/Default.aspx");
}
But now when I refresh page or go to another page I still see "Thx for email." but user should see it only once.
You can clear out the Session["msg"] on Page_load (outside of the if(!isPostback))
Or you can create a label on the master page, access that through the child pages to put the message in there, and clear that one on Page load, this gets you away from using Session. Using a Label you can also set the cssClass, allowing bolding, color changes (red for errors, green for success, etc).
If you just want a plan message you could aways go with a literal control, less over head.
This is because Session variable having their value throghout the session.
Session["msg"]
will always have same value on all the pages in a session.
If you want that value should only be used for the page where you redirect then you can use querystring.
protected void Send_Click(object sender, EventArgs e)
{
Session["msg"] = "Thx for email.";
Response.Redirect("~/Default.aspx?msg='true'");
}
then on SiteMaster
<% if(Request.QueryString["msg"]!=null) Response.Write(Session["msg"].ToString()); %>
You have to set Session["msg"] = null after you show the message. Session lives in server at defualt of 20 min. If you do not set it null it will appeear
Try setting the Session["msg"] to null once it is printed on the page.
i'm a beginner in .NET, and search since yesterday morning to resolve my problem without finding the solution.
Here is my problem :
I create dynamically some User Controls by this way, because I need to give parameters :
List<ANNOUNCEMENT> listAnnouncement = getAnnoucements();
foreach(ANNOUNCEMENT ann in listAnnouncement)
{
if(ann.IS_CURRENT_ANNOUNCEMENT && currentAnnouncement == null)
{
currentAnnouncement = ann;
}
List<Object> listParams = new List<Object>();
listParams.Add(ann);
AnnouncementPresentation ap = (AnnouncementPresentation)(Controller.LoadControl(Page, "~/UserControls/AnnouncementPresentation.ascx", listParams.ToArray()));
/* important for the end of the method */
ap.modifyAnnouncementButtonClick += new EventHandler(modifyAnnouncementButtonClick);
pnl_announcements.Controls.Add(ap);
}
In this ASCX, I have a button, and when user will click on it, I want to call a method contained in my ASPX, so I do this in the ASCX :
public event EventHandler modifyAnnouncementButtonClick;
protected void btn_modify_announcement_Click(object sender, EventArgs e)
{
PageAdminAnnonces.currentAnnouncement = annonce;
modifyAnnouncementButtonClick(sender, e);
}
And this in the ASPX :
protected void modifyAnnouncementButtonClick(object sender, EventArgs e)
{
initListOfAnnouncement();
lbl_errors.Text = currentAnnouncement.TITLE;
}
I think everything works, but there is the problem : It works once, and at the end of the method, I delete my ASCX as you can see, and create new ASCX. But they don't have the methods, and when I click again, nothing works, so the ASPX is reloaded. After reloading, it works again.
Do i do something wrong?
According to the information in the comments, I suppose that your solution does not work because you are recreating the controls in the Click event handling method, which is very late in the page's lifecycle and should not be used for adding controls.
As mentioned in the comments, I suggest you to create the controls in Page_Init or Page_Load and not recreate them in the button's Click handling method. You should also assign a unique ID to each of them. Then, in the Click handler, you can use FindControl method to acces the created controls. Alternatively you can just save the references to the controls upon creation, so you can access them later easily.
Useful links:
http://msdn.microsoft.com/en-us/library/ms178472.aspx
http://visualstudiomagazine.com/articles/2010/10/11/more-on-adding-controls-dynamically.aspx
I have problem passing a variable from a main page containing a user control to the user control itself. Although the passed variable is available generally in the code-behind of the user control the page_load event can't seem to read it.
My code -
In the main page code-behind:
protected void FindCCFsButton_Click(object sender, EventArgs e)
{
if (CustomerDropDown.SelectedIndex != 0)
{ SearchUcCCFList.SetCustID(CustomerDropDown.SelectedValue); }
}
(SearchUcCCFList is the instance of the user control in the main aspx page).
In the user control code behind:
public partial class ucCCFList : System.Web.UI.UserControl
{
public string srchCust { get; set; }
public void SetCustID(string custID)
{
srchCust = custID;
testCustLabel.Text = GetCustID(); //this works
}
public string GetCustID()
{
return srchCust;
}
protected void Page_Load(object sender, EventArgs e)
{
CCFGridView.DataSource = DAL.SearchCCFs(custID : GetCustID()); //doesn't work
CCFGridView.DataBind();
test2CustLabel.Text = GetCustID(); //doesn't work
}
In the Page_Load event GetCustId() doesn't return anything (so the records aren't filtered and all get returned) although it can be read in the methods outside the Page_Load.
I'm probably making a beginners error but any help would be appreciated.
Edit - following Alan's suggestion in the comments I stepped through the page loading sequence & it appears that the user control's Page_Load event is running BEFORE the code in the main page's button click so the variable is not yet available. The sequence after clicking the button is:
User control Page_Load runs
Code in button event on main page
Other code (outside Page_Load) in user control runs hence variable is available here.
This seems a bit weird, is there another way to pass the variable into the user controls Page_Load?
In this case, your click handling even on the main page is called after the user control page load call. Your variable is being set, but not until after your data binding in the user control.
Either switch the user control to declarative binding which will handle calling methods in the correct order for you. Or the easier fix in this case is to change the user control data binding from Page_Load to Page_PreRender, which is called later in the life cycle, after the main page click handling call.
protected void Page_PreRender(object sender, EventArgs e)
{
CCFGridView.DataSource = DAL.SearchCCFs(custID : GetCustID()); // will work now
CCFGridView.DataBind();
test2CustLabel.Text = GetCustID(); // will work now
}
For a more thorough answer, read up on the ASP.NET page life cycle including the interaction with user controls' life cycle.
I've written a custom widget to allow a user to select a location from a database of locations. This is my first ASP.net custom control. It seemed like everything was working fine, but now there's a problem.
My control implements the RaisePostBackEvent function as follows:
public void RaisePostBackEvent(string eventArgument)
{
SelectedLocationId = eventArgument.Split('|')[0];
SelectedLocationDescription = eventArgument.Split('|')[1];
}
I wrote a test page and included the following in my ASP code:
<%= locationSelector.SelectedLocationId %>
That worked fine.
However, in my web application, the following code does not work:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
Response.Write(locationSelector.SelectedLocationId);
// SelectedLocationId is null here!!!
}
When I run this code in the debugger, I see that my Page Load event fires before the Post Back event! Therefore, the data is not yet read from the postback. I know that using the MS provided text field control, the text is available at Page Load, so I think I must be doing something wrong.
How can I read the location that the user selected when the Page Load event fires? To clarify, I'm refering to the Page Load of a web application page.
You're setting SelectedLocationId on a postback event and at the same time you are trying to retrieve its value on the first load. SelectedLocationId will be null all right.
Try:
protected void Page_Load(object sender, EventArgs e)
{
if (locationSelector != null)
Response.Write(locationSelector.SelectedLocationId);
}