Develop Reference

passing an argument from an aspx page to a UserControl

I am having a problem passing a variable to a user control.
When I pass a hard-coded value, my control works fine. However passing a variable is not working.
My ASPX code:
<% System.Console.Out.WriteLine("Operate Flag is set to: " + operateFlag); %>
<uc:menu ID="navigationMenu" runat="server" operate="<%# operateFlag %>" />
From debug output, it is clear that operateFlag is set to 'true'.
My control codebehind only has synthesized methods as below:
public partial class MenuControl : System.Web.UI.UserControl
{
public bool operate { get; set; }
}
I also print out the received value from inside the control:
<% System.Console.Out.WriteLine("Operate Flag is received as: \'" + operate + "\'"); %>
Here, operate is received by the control as False.

I figured out a way to get my page working. Still do not understand what was wrong with the original "form."
Now, as before from OnLoad(), I set the property of the control instead of passing a variable as:
navigationMenu.operate = false;
It solves my need.

Pass values from page to user control

I am storing name and last name in two labels in main page. I also have those values in a class (class doesnt do much but i am using them for future expansion). I have a user control that will send an email with name and last name as body.
My question is that how can I transfer label or class variable values into user control's body variable?

Create a property on your user control with the datatype of the data you want to pass to it, and populate it in your page on creation of the control.
public class myUserControl : Control
{
...
public int myIntProperty {get; set;}
...
}
Later this in the code behind you can assign the value like
myUserControl cntrl = new myUserControl();
cntrl.myIntProperty = 5;
Instead of this you can pass the value through Markup also like
<uc1:myUserControl ID="uc1" runat="server" myIntProperty="5" />

You need to create properties on your control to hold these values; then from the page code, simply assign the values to the properties in the control.
On your control, you can have something like
public string FirstName
{
get {
if (ViewState["FirstName"] == null)
return string.Empty;
return ViewState["FirstName"].ToString();
}
set {
ViewState["FirstName"] = value;
}
}

You need to define public properties on the control and then when you use control on the page you can pass values to those parameters.
Something like:
<cc:mycustomControl runat="server"
MyProperty1=<%# label1 %>
MyProperty2=<%# label2 %>
/>

Step 1:
You can expost the values as property and than you can make use of that easily.
Step 2: To access your page from the user control you can make use of Parent property or may be some custome login to access the parent page and than write code to consume the property value.

you can do something like this in your user control
string x=((yourparentcontrol)this.parent).label1.text;
and use the string x.

How can i access a server side control from asp.net code behind file using reflection?

For example, if i have on the aspx page:
<asp:PlaceHolder ID="tab_0" runat="server" Visible="false"></asp:PlaceHolder>
<asp:PlaceHolder ID="tab_1" runat="server" Visible="false"></asp:PlaceHolder>
and i want to access these properties in the code behind page using values from a configuration file for example
string enabledTabs = "0,1,2,3";
if there a way i can use reflection to set them to enabled or disabled e.g.
foreach(var id in enabledTabs.Split(','))
{
// <use reflection to get the correct tab control>
// Set property of the tab
tab.Visible = true;
}
I could acheive the result i want by using a switch statement and setting the particular control property, but i'd like to use reflection to get the tab to make it cleaner.
Could anyone help?
Thanks!

You don't need reflection. Use Page.FindControl:
foreach(var id in enabledTabs.Split(','))
{
PlaceHolder control = (PlaceHolder)this.FindControl("tab_"+id));
control.Visible = true;
}

foreach(var id in enabledTabs.Split(','))
{
// Set property of the tab
Page.FindControl("tab_" + id.ToString()).Visible = true;
}

Try the following:
Control tab = Control.FindControl("tab_"+id);

C# custom control to get internal text as string

ok, I'm working on a custom control that can contain some javascript, and read this out of the page into a string field.
This is a workaround for dynamic javascript inside an updatepanel.
At the moment, I've got it working, but if I try to put a server tag inside the block:
<custom:control ID="Custom" runat="server">
<%= ControlName.ClientID %>
</custom:control>
The compiler does not like it. I know these are generated at runtime, and so might not be compatible with what I'm doing, but does anyone have any idea how I can get that working?
EDIT
Error message is: Code blocks are not supported in this context
EDIT 2
The control:
[DataBindingHandler("System.Web.UI.Design.TextDataBindingHandler, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"), ControlValueProperty("Text"), DefaultProperty("Text"), ParseChildren(true, "Text"), AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal), AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public class CustomControl : Control, ITextControl
{
[DefaultValue(""), Bindable(true), Localizable(true)]
public string Text
{
get
{
return (string)(ViewState["Text"] ?? string.Empty);
}
set
{
ViewState["Text"] = value;
}
}
}

The compiler is write, server side code blocks are only supported within the context of an ITemplate.
The "Text" property should be set like this ...
<custom:control ID="Custom" runat="server" Text="YourText">
Using ITemplate you can declare it in the codebehind as ...
public ITemplate Text
{
get;
set;
}
But then you would need to do this ...
<custom:control ID="Custom" runat="server">
<Text><%= ControlName.ClientID %></Text>
</custom:control>
Having said that, if you have a custom control why not just do this in the code behind ...
this.text = ((ITextControl)Page.FindControl(controlName)).Text;
Trouble is, it's not very dynamic.
I would favour the templated option.
Harder to implement though.

Validating Form Fields in an ITemplate

I have a custom control which includes a property of the following definition:
[PersistenceMode(PersistenceMode.InnerProperty)]
public ITemplate Template {
get { return template; }
set { template = value; }
}
The control overrides CreateChildControls(), and adds several HtmlGenericControls and an asp:Panel control.
The actual actual implementation of the control looks something like this:
<user:Frame runat="server">
<Template>
<asp:Literal runat="server" ID="SomeControl" Text="SomeValue" />
</Template>
</user:Frame>
While the page renders as intended, it has a number of consequences of varying severity, including:
Controls enclosed within the Template cannot be referenced directly, and FindControl is required. This is fine.
I've been unable to use validation controls on them.
Is there a better way to design my custom control? Or perhaps just a way to get validation working?

By default the framework assumes that you may have more than one template in a control, like say in a Repeater. In your case you have to tell it that you intend to have a single template by using the TemplateInstance property. E.g.
[PersistenceMode(PersistenceMode.InnerProperty)]
[TemplateInstance(TemplateInstance.Single)]
public ITemplate Template {
get { return template; }
set { template = value; }
}
This will allow you to reference the templated controls directly, and should fix your validation problems as well.

One way to get validation to work in this case is to add the validation controls programatically. For example:
var c = parentControl.FindControl("id");
parentControl.Controls.AddAt(
parentControl.Controls.IndexOf(c) + 1,
new RequiredFieldValidator() { ControlToValidate = c.D });