<%# Register Src="~/Controls/PressFileDownload.ascx" TagName="pfd" TagPrefix="uc1" %>
<asp:Repeater id="Repeater1" runat="Server" OnItemDataBound="RPTLayer_OnItemDataBound">
<ItemTemplate>
<asp:Label ID="LBLHeader" Runat="server" Visible="false"></asp:Label>
<asp:Image ID="IMGThumb" Runat="server" Visible="false"></asp:Image>
<asp:Label ID="LBLBody" Runat="server" class="layerBody"></asp:Label>
<uc1:pfd ID="pfd1" runat="server" ShowContainerName="false" ParentContentTypeId="55" />
<asp:Literal ID="litLayerLinks" runat="server"></asp:Literal>
</ItemTemplate>
</asp:Repeater>
System.Web.UI.WebControls.Label lbl;
System.Web.UI.WebControls.Literal lit;
System.Web.UI.WebControls.Image img;
System.Web.UI.WebControls.HyperLink hl;
System.Web.UI.UserControl uc;
I need to set the ParentItemID variable for the uc1:pdf listed inside the repeater.
I thought I should be able to find uc by looking in the e.Item and then setting it somehow. I think this is the part where I'm missing something.
uc = (UserControl)e.Item.FindControl("pfd1");
if (uc != null) { uc.Attributes["ParentItemID"] = i.ItemID.ToString(); }
Any thoughts would be appreciated.
Also tried this with similar results... when I debug inside my usercontrol (pfd1) the parameters I am trying to set have not been set.
uc = (UserControl)e.Item.FindControl("pfd1");
if (uc != null)
{
uc.Attributes.Add("ContainerID", _cid.ToString());
uc.Attributes.Add("ParentItemId", i.ItemID.ToString());
}
UPDATE: It looks like my controls are not connected by a namespace. I've wrapped by the parent control (Layer) and the PressFileDownlad control in a namespace "MyControls". Also updated their Inherits reference on the aspx to read "MyControls.xxxxx". I'm able to type "MyControls.Layer" inside the code on layer.aspx.cs but I'm not able to get "MyControls.PressFileDownload"
If you implement ParentItemID as a public property in your user control, then you should be able to set it declaratively, e.g:
<asp:Repeater id="Repeater1" ...>
<ItemTemplate>
<uc1:pfd ID="pfd1" runat="server" ParentItemId='<%# Eval("ItemID") %>' ... />
Martin is right you should be able to set it in declarative way (in case your property is public) .
But your way should also work (just cast it properly)
((PressFileDownload)e.Item.FindControl("pfd1")).ParentItemId = 0;
The best way is to implement the OnDataBinding event for the user control. I try to stay away from putting code inline in the aspx using webforms if possible.
When the repeater gets bound, for each item that is bound, the OnDataBinding will fire for your user control and your handler can do what it needs. You don't have to go searching for the controls.
Here is an example:
// in your aspx
<uc1:pfd ID="pfd1" runat="server" ShowContainerName="false" ParentContentTypeId="55"
OnDataBinding="pfd1_DataBinding" />
// in your codebehind implement the OnDataBinding event
protected void pfd1_DataBinding(object sender, System.EventArgs e)
{
pfd uc = (pfd)(sender);
uc.ContainerID = _containerID.ToString();
uc.ParentItemID = Eval("ItemID");
// Here you can do more like access other items like hidden fields
// or cached objects or even other controls etc... Skys the limit.
}
EDIT: Notice from your comment you require more data than what is found in the datasource. In this case what I usually do is just make private member variables in the .cs that I store data in. So when you have the container ID just store it in a variable that will be accessible.
Eg in your .cs for your page:
public partial class _TestPage : System.Web.UI.Page
{
private int _containerID { get; set; }
Then when you load the data just set the _containerID property and it will be accessible in the OnDataBinding event. Just make sure you are binding after you have set the _containerID.
Related
Ok, I've already learned that in order to keep the dynamic (created) controls and their viewstate in asp.net we must (re)create them in the Page init event, so they already exist within the page's control hierarchy before the view state is loaded.
As it says in this article.
There is no problem to achieve this behaviour if the criteria to create these controls is outside the web environment, for example a database. But what should I do if what I use to decide how many dynamic controls I have to create is actually a value that is in the controls?
I try to explain it with an example, maybe it's clearer:
Let's say that we have a textbox and two buttons. In the textbox I write the number of how many dynamic controls I want to create, for example 4 checkbox. When I hit the button1 the controls should be created. No problem. Then I check some checkboxes and hit the button2 just to fire a postback. Now I should recreate the controls in the page init event, like we said before, in order to maintain the controls and their state.
And here comes the problem. Because of I'm in the init stage I have no viewstate so I'm no able to access the value in the textbox that tells me how many dynamic checkbox should I create.
I thought that storing the value in the session object would do the trick, but it doesn't. The session object is no accessible as well.
Where can I save the value that it'll be accessible from the init event too?
Thanks and sorry for the long post!
First thing - textbox value is not stored/retrieved from view state, you cannot get textbox value from viewstate.
Coming to actual problem, here is the sequence of (imp) events init -> load view state -> bind postback data -> page load. You can retrieve textbox value only after bind postback data event (which actually takes posted data and binds to the textbox control).
In init only option is to use Request.Form{"textboxid"] to get the textbox value.
You are on the right track.
If you use TextBox, you do not need another ViewState to keep track of how many controls has been created, because TextBox control has its own ViewState already.
You can use either Page_Init or Page_Load to load control back.
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs"
Inherits="WebApplication2010.WebForm1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:TextBox runat="server" ID="NumberTextBox" />
<asp:Button runat="server" ID="CreateControlButton"
OnClick="CreateControlButton_Click"
Text="Create Control" />
<br />
<asp:PlaceHolder runat="server" ID="PlaceHolder1"></asp:PlaceHolder>
</div>
</form>
</body>
</html>
using System;
using System.Web.UI;
namespace WebApplication2010
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
int ids;
if (Int32.TryParse(NumberTextBox.Text, out ids))
{
for (int i = 0; i < ids; i++)
{
Control ctrl = Page.LoadControl("WebUserControl.ascx");
ctrl.ID = i.ToString();
PlaceHolder1.Controls.Add(ctrl);
}
}
}
}
protected void CreateControlButton_Click(object sender, EventArgs e)
{
}
}
}
<%# Control Language="C#" AutoEventWireup="true"
CodeBehind="WebUserControl.ascx.cs"
Inherits="WebApplication2010.WebUserControl" %>
<asp:CheckBox runat="server" ID="CheckBox1" />
<asp:Button runat="server" ID="Button1" OnClick="Button_Click"
Text="Post Back" />
<asp:Label runat="server" ID="Label1" />
<br />
using System;
namespace WebApplication2010
{
public partial class WebUserControl : System.Web.UI.UserControl
{
protected void Button_Click(object sender, EventArgs e)
{
Label1.Text = " This control was posted back.";
}
}
}
This is the common paradox with page lifecycle when you work with code behind. For example, you save the editing customerid in viewstate but controls need to bind on init to be able to read their posted values.
Best real life solution is to do what bound controls do on postback, call explicilately the LoadPostBackData on IPostBackDataHandler interface that all controls implement, after you have created them in Page Load event.
You should create an extension method for Controls and call it when needed:
control.DataBind();
control.LoadPostedData(); // extension method
I have a user control that have a gridview, buttons and a multi-line textbox for comments.
When the page posts back, Gridview is behaving normaly (its controls keeps their values after postback). However, the Comment textbox is always empty, no matter what I do.
protected void Page_Load(object sender, EventArgs e)
{
//This code is in the user ciontrol.
if (!IsPostBack)
{
string test = this.txtDepartmentComments.Text;
}
}
I put a break point at that line and the value is always empty. I've tried also to set the value in the code behind like:
protected void Page_Load(object sender, EventArgs e)
{
//This code is in the user ciontrol.
if (!IsPostBack)
{
this.txtDepartmentComments.Text = "Test!";
}
}
But when the page loads, the control remain empty.
Any idea why this is hapenning?
EDIT
This the ascx code (i.e. user control)
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns = "false" >
</asp:GridView>
<asp:TextBox ID="txtComments" runat="server" Columns="45" TextMode= "MultiLine"/>
<asp:Button ID="btnComplete" runat="server" Text="Completed"/>
And thid id the aspx (i.e. the parent page)
<asp:Repeater ID="rpNewHire" runat="server">
<HeaderTemplate>
<table>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<user:MyUserControl ID = "MyUserControl1" runat = "server"
DepartmentID= '<%# Eval("DepID")%>'><user:MyUserControl />
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
if(!IsPostBack) is for reading values from controls after postback, you are trying to read text box value on initial load which will always be empty, remove the '!' from your condition. Also it is hard to debug your issue with out the aspx page contents, try posting the design part as well in your question.
EDIT
Your user tag is not well formatted inside repeater, it is missing closing tag and runat attribute
<user:MyUserControl runat="server" ID = "MyUserControl1" DepartmentID= '<%# Eval("DepID")%>'></user:MyUserControl>
Controls inside repeater cannot be accessed directly, you have to loop through the rows of the repeater and find your child controls and then try reading values from them, that after you bind some data to the repeater.
Check this http://msdn.microsoft.com/en-us/magazine/cc163780.aspx
Page's IsPostBack and each user controls' IsPostBack are not same.
When a user control is posted back, that particular control's IsPostBack is true, but other user controls' IsPostBack are still false.
You can use explicitly !Page.IsPostBack inside a user control to check whether its parent page is posted back or not.
if(!Page.IsPostBack){
// do something
}
Dynamically Loaded Control can not maintain values at PostBack? It is not directly related to your question, but it might be useful for you.
I am bit new to C# and got a question.
I have a class as below that simply return false ( this is just to test)
public class SetAuthority
{
public SetAuthority()
{
//
// TODO: Add constructor logic here
//
}
public static Boolean AuthorizedToAddEdit()
{
return false;
}
}
I have a DetailsView with two link buttons to Edit and add New record. I want to hide the link buttons based on the above class method returning value.
<ItemTemplate>
<asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" visible='<%# SetAuthority.AuthorizedToAddEdit() %>'
CommandName="Edit" Text="Edit"></asp:LinkButton>
<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" visible='<%# SetAuthority.AuthorizedToAddEdit() %>'
CommandName="New" Text="New"></asp:LinkButton>
</ItemTemplate>
Above works file and Edit and New link buttons are hidden when I run the program.
But the question is, I have a separate link button outside of the DetailsView. It is just a link to navigate to another page. I want to hide this in similar way using the same logic. I have the below code in my webform.
<asp:LinkButton ID="LinkButton5" runat="server" CausesValidation="False" visible='<%# SetAuthority.AuthorizedToAddEdit() %>'
CommandName="OpenAdminPage" Text="Open Admin Page"></asp:LinkButton>
But the link button is always visible and seems it is not calling the class and not getting the value back. It appeared to be the class not return any value and can someone help me to identify what is the different between having this and working in DetailsView and not working for a simple link button.
Note: have a workaround where I can call the same method in Page Load event that works fine without any issue. Code is below
protected void Page_Load(object sender, EventArgs e)
{
Boolean myAllowAdd;
myAllowAdd = SetAuthority.AuthorizedToAddEdit();
if (myAllowAdd == false)
{
LinkButton1.Visible = false;
}
}
The reason is that this is for databinding expressions only: <%# Since the DetailsView is databound it works there.
If you would DataBind the page it worked also for the LinkButton outside of the DetailsView:
protected void Page_Load(object sender, EventArgs e)
{
Page.DataBind();
}
inline asp.net tags... sorting them all out (<%$, <%=, <%, <%#, etc.)
Side-note: be careful with static in ASP.NET. The static method does not yet hurt. But if you'd also use static fields you'd enter a minefield since it would be shared across all requests. Your current code-behind "work-around" is the better approach anyway.
I'm designing my own custom control that contains a .NET dropdownlist. What I'm wondering is if it is possible to populate my dropdownlist with listitems placed in a placeholder?
For example:
<asp:DropDownList ID="ddlFilter" runat="server" >
<asp:PlaceHolder ID="ListItemPlaceholder" runat="server"/>
</asp:DropDownList>
This doesn't work because the DropDownList control only allows ListItems as child controls. But, I want to do something similar to this so when the user includes my control on a page, they can do something like this:
<mytag:MyControl Mode="DropDown" runat="server">
<ListItemTemplate>
<asp:ListItem Text="C" Value="c"></asp:ListItem>
<asp:ListItem Text="E" Value="e"></asp:ListItem>
<asp:ListItem Text="B" Value="b"></asp:ListItem>
</ListItemTemplate>
</myTag:MyControl>
Any suggestions or ideas? I know I can do this by dynamically adding the ListItems in the page code behind, but I'd like to avoid that if possible. Thanks!
One approach to this would be to give your control a [ParseChildren(true, "ListItemTemplate")] attribute.
If you then had a property called "ListItemTemplate", which was an array of ListItems, your markup would be parsed into that property. At runtime in your control, you could simply hand your dropdownlist the contents of that property.
Some non-tested example code:
[ParseChildren(true, "ListItemTemplate")]
public class MyControl: Control
{
private ArrayList employees = new ArrayList();
private DropDownList myDropDownList = new DropDownList();
public ArrayList ListItemTemplate
{
get
{
return employees;
}
}
protected override void CreateChildControls()
{
myDropDownList.Items.AddRange(ListItemTemplate):
Controls.Add(myDropDownList);
}
}
I'm using a public variable called IsAdmin in the code behind of an aspx page.
public partial class _news : System.Web.UI.Page
{
public bool IsAdmin = false;
protected void Page_Load(object sender, EventArgs e)
{
if (User.Identity.Name.Contains("admin"))
{
IsAdmin = true;
}
else
{
IsAdmin = false;
}
}
And i use the property Visible='<%#IsAdmin%>' to assign to panels which i want to show if the user is an admin in the aspx design of the page. Strangely it works for the linkbuttons i've put on the repeater.
<asp:Panel ID="Panel1" runat="server" Visible='<%#IsAdmin%>'>
<asp:LinkButton ID="LinkButton2" runat="server" PostBackUrl='<%# "news_edit.aspx? Action=edit&id=" + Convert.ToString( Eval("news_id")) %>Edit</asp:LinkButton>
<asp:LinkButton ID="LinkButton3" runat="server" PostBackUrl='<%# "news.aspx?Action=delete&id=" + Convert.ToString( Eval("news_id")) %>'>Delete</asp:LinkButton>
</asp:Panel>
and it works fine, however outside the repeater i've put another linkbutton without a panel
<asp:LinkButton ID="LinkButton4" runat="server" PostBackUrl="~/news_edit.aspx?action=new" Visible='<%#IsAdmin%>'>Add New Item</asp:LinkButton>
but the visible property doesn't work on it! I tried putting it inside a panel too and setting it's visible property but that too didn't work.
So i have following doubts
1)what is the issue?
2)what is the technical name when we use references like '<%#IsAdmin%>' in the design page
3)Does page load happen before page is rendered of after page is rendered?
Thanks
<%# %> is the syntax used for accessing databound fields. Since you are likely databinding the Repeater control at some point, these expressions will be evaluated.
Since you are likely not calling databind on the Panel and the Linkbuttons outside of the Repeater, these expressions will not be processed. You can probably change them to something like
<%= IsAdmin.ToString() %>
and get the result you want.
Check this great blog entry for more information on the differences.
Also, Page Load happens before the page is rendered. Rendering the page is the last thing that happens in the ASP.Net page lifecycle.