I make all controls on a form read-only at once:
private static void DisableControl(Control control)
{
PropertyInfo enProp = control.GetType().GetProperty("Enabled")
if (enProp != null)
{
enProp.SetValue(control, false, null);
}
foreach (Control ctrl in control.Controls)
{
if (ctrl.ID != "HyperLinkExcelOrder")
DisableControl(ctrl);
}
}
I don't want disable HyperLinkExcelOrder, but this function disabled it.
When I use HyperLinkExcelOrder.Enabled=true; It still is disabled.
You can just set enabled = false on the from. Child Enabled properties will take the value of their parent automaticly. And then set the Hyperlink control on enabled = true. There is not need for DisableControl code.
I´ve a base class for all user controls: SiteUserControlBase. It also takes a typeparam: SiteUserControlBase<T>. How do I best find all controls on the page that derives from SiteUserControlBase regarding of the typeparam?
I use the extension method below to find all controls of type SiteUserControlBase, but it will exclude all controls that also uses the type param.
public static IEnumerable<T> FindControlsOfType<T>(this ControlCollection Controls)
where T : class
{
T control;
foreach (Control ctrl in Controls)
{
if ((control = ctrl as T) != null)
{
yield return control;
}
foreach (T child in FindControlsOfType<T>(ctrl.Controls))
{
yield return child;
}
}
}
In the ascx.cs file I'm dynamically generating buttons. In .aspx file I add the control to the form. The control itself renders well, but when the buttons are clicked I get this error
An error has occurred because a control with id 'ctl03' could not be
located or a different control is assigned to the same ID after
postback.
DestopControl.ascx.cs
public partial class DesktopControl : PlaceHolder
{
public void Build()
{
for (int i = 0; i < 10; i++)
{
Button button = new Button()
{
Width = 50,
Height = 50,
ID = string.Format("button{0}", i),
Text = i.ToString()
};
button.Click+=new EventHandler(button_Click);
}
}
}
Default.aspx.cs
DesktopControl desktop = new DesktopControl();
desktop.Build();
MainContent.Controls.Add(desktop);
After reading the comments (little hard to read the code-part of the comments) it appears that yes, you are generating your controls inside an if(!isPostBack){}; well, looks like it's in the else part of that if statement.
You have to generate your controls every time the page posts back, as the page_load gets fired before your button click. So once the controls have been re-created the code will continue on to your button click handler, where the controls should be available to handle.
Essentially, take ReloadUI(Session["ui"]); OUT of the if(!isPostBack){}else{} statement. Put it after your if statement.
Like this:
if (!isPostBack){
// my first load code
}else{
// my postback code
}
// load all my dynamic controls here
ReloadUI(Session["ui"]);
Found a solution:
Every time there is a new UI I call this ClearScreen() which does the trick.
The error on 'ctl03' was a menu control which was generating it's own ID and somehow wasn't available on postback. I assigned an ID to it. But I guess all the issue went away with this ClearScreen() method.
private void ClearScreen()
{
try
{
List<Control> controls = new List<Control>();
foreach (Control control in MainContent.Controls)
{
controls.Add(control);
}
for (int i = 0; i < controls.Count; i++)
{
if (!(controls[i].GetType() == typeof(LiteralControl) || controls[i].GetType() == typeof(ScriptManager)))
{
MainContent.Controls.Remove(controls[i]);
}
}
}
catch (Exception ex)
{
}
}
I'm experiencing some problems and right now I don't know how to solve it. The web control simply updates a clock represented by a label every second. My issue is that the web control exposes a property called 'Formato' where the user can select to display in format 12 or 24 hours. This is done with an enum type where in spanish Doce means 12 and Veinticuatro means 24. This is the code for the server control:
namespace Ejercicio2RelojControl
{
public enum _FormatoHora
{
Doce,
Veinticuatro
}
[DefaultProperty("FormatoHora")]
[ToolboxData("<{0}:Ejercicio2RelojControl runat=server></{0}:Ejercicio2RelojControl>")]
[ToolboxBitmap(typeof(Ejercicio2RelojControl), "Ejercicio2RelojControl.Ejercicio2RelojControl.ico")]
//[Designer("Ejercicio2RelojControl.Ejercicio2RelojControlDesigner, Ejercicio2RelojControl")]
public class Ejercicio2RelojControl : WebControl
{
public Ejercicio2RelojControl()
{
}
[
//Bindable(true),
Category("Appearance"),
//DefaultValue(_FormatoHora.Doce),
Description(""),
]
public virtual _FormatoHora FormatoHora
{
get
{
//object t = ViewState["FormatoHora"];
//return (t == null) ? _FormatoHora.Doce : (_FormatoHora)t;
object obj2 = this.ViewState["_FormatoHora"];
if (obj2 != null)
{
return (_FormatoHora)obj2;
}
return _FormatoHora.Doce;
}
set
{
ViewState["_FormatoHora"] = value;
}
}
//Create one TimerControl
Timer timer = new Timer();
private Label clockLabel = new Label();
// Declare one Updatepanel
UpdatePanel updatePanel = new UpdatePanel();
// Now override the Load event of Current Web Control
protected override void OnLoad(EventArgs e)
{
//Text = "hh:mm:ss";
// Create Ids for Control
timer.ID = ID + "_tiker";
clockLabel.ID = ID + "_l";
// get the contentTemplate Control Instance
Control controlContainer = updatePanel.ContentTemplateContainer;
// add Label and timer control in Update Panel
controlContainer.Controls.Add(clockLabel);
controlContainer.Controls.Add(timer);
// Add control Trigger in update panel on Tick Event
updatePanel.Triggers.Add(new AsyncPostBackTrigger() { ControlID = timer.ID, EventName = "Tick" });
updatePanel.ChildrenAsTriggers = true;
// Set default clock time in label
clockLabel.Text = DateTime.Now.ToString("h:mm:ss tt");
//clockLabel.Text = DateTime.Now.ToString("H:mm:ss");
// Set Interval
timer.Interval = 1000;
// Add handler to timer
timer.Tick += new EventHandler<EventArgs>(timer_Tick);
updatePanel.RenderMode = UpdatePanelRenderMode.Block;
//Add update panel to the base control collection.
base.Controls.Add(updatePanel);
}
protected override void RenderContents(HtmlTextWriter output)
{
output.Write(FormatoHora);
}
void timer_Tick(object sender, EventArgs e)
{
// Set current date time in label to move current at each Tick Event
clockLabel.Text = DateTime.Now.ToString("h:mm:ss tt");
//clockLabel.Text = DateTime.Now.ToString("H:mm:ss");
}
}
}
Now it's time to test the custom control in an asp.net web application.
<cc1:Ejercicio2RelojControl ID="Ejercicio2RelojControl1" runat="server" />
Works great! BUT when I add the property "Formato" fails at compile time:
<cc1:Ejercicio2RelojControl ID="Ejercicio2RelojControl1" runat="server" Formato="Doce" />
Compiler Error Message: CS0117: 'Ejercicio2RelojControl.Ejercicio2RelojControl' does not contain a definition for 'FormatoHora'
Why is the property Formato making the web app crash at compile time?
Thanks a lot.
EDIT:
namespace Ejercicio2RelojControl
{
public enum FormatoHora
{
Doce,
Veinticuatro
}
[DefaultProperty("FormatoHora")]
[ToolboxData("<{0}:Ejercicio2RelojControl runat=server></{0}:Ejercicio2RelojControl>")]
public class Ejercicio2RelojControl : WebControl, INamingContainer
{
public FormatoHora FormatoHora
{
get
{
object obj2 = this.ViewState["FormatoHora"];
if (obj2 != null)
{
return (FormatoHora)obj2;
}
return FormatoHora.Doce;
}
set
{
ViewState["FormatoHora"] = value;
}
}
As you can see I've changed the public property. Now the error has changed. Is the following:
Compiler Error Message: CS0120: An object reference is required for the non-static field, method, or property 'Ejercicio2RelojControl.Ejercicio2RelojControl.FormatoHora.get'
Any help appreciated. Thanks
EDIT 2:
I've discovered that the problem is on the set {}. If I comment it, all is working fine but then I cannot change FormatoHora between 12 and 24 because of is read only due to only get{} is implemented. Any help with the implementation of set{} ?
I am here for giving you the solution:
You are using the same name for the namespace and for the webcontrol (Ejercicio2RelojControl) . Simply change that and your code will work fine.
Hope it helps, despite the fact some years have passed :)
I have a complex asp.net form,having even 50 to 60 fields in one form like there is Multiview, inside MultiView I have a GridView, and inside GridView I have several CheckBoxes.
Currently I am using chaining of the FindControl() method and retrieving the child ID.
Now, my question is that is there any other way/solution to find the nested control in ASP.NET.
If you're looking for a specific type of control you could use a recursive loop like this one -
http://weblogs.asp.net/eporter/archive/2007/02/24/asp-net-findcontrol-recursive-with-generics.aspx
Here's an example I made that returns all controls of the given type
/// <summary>
/// Finds all controls of type T stores them in FoundControls
/// </summary>
/// <typeparam name="T"></typeparam>
private class ControlFinder<T> where T : Control
{
private readonly List<T> _foundControls = new List<T>();
public IEnumerable<T> FoundControls
{
get { return _foundControls; }
}
public void FindChildControlsRecursive(Control control)
{
foreach (Control childControl in control.Controls)
{
if (childControl.GetType() == typeof(T))
{
_foundControls.Add((T)childControl);
}
else
{
FindChildControlsRecursive(childControl);
}
}
}
}
Late as usual. If anyone is still interested in this there are a number of related SO questions and answers. My version of recursive extension method for resolving this:
public static IEnumerable<T> FindControlsOfType<T>(this Control parent)
where T : Control
{
foreach (Control child in parent.Controls)
{
if (child is T)
{
yield return (T)child;
}
else if (child.Controls.Count > 0)
{
foreach (T grandChild in child.FindControlsOfType<T>())
{
yield return grandChild;
}
}
}
}
All the highlighted solutions are using recursion (which is performance costly). Here is cleaner way without recursion:
public T GetControlByType<T>(Control root, Func<T, bool> predicate = null) where T : Control
{
if (root == null) {
throw new ArgumentNullException("root");
}
var stack = new Stack<Control>(new Control[] { root });
while (stack.Count > 0) {
var control = stack.Pop();
T match = control as T;
if (match != null && (predicate == null || predicate(match))) {
return match;
}
foreach (Control childControl in control.Controls) {
stack.Push(childControl);
}
}
return default(T);
}
FindControl does not search within nested controls recursively. It does only find controls that's NamigContainer is the Control on that you are calling FindControl.
Theres a reason that ASP.Net does not look into your nested controls recursively by default:
Performance
Avoiding errors
Reusability
Consider you want to encapsulate your GridViews, Formviews, UserControls etc. inside of other UserControls for reusability reasons. If you would have implemented all logic in your page and accessed these controls with recursive loops, it'll very difficult to refactor that. If you have implemented your logic and access methods via the event-handlers(f.e. RowDataBound of GridView), it'll be much simpler and less error-prone.
Action Management On Controls
Create below class in base class.
Class To get all controls:
public static class ControlExtensions
{
public static IEnumerable<T> GetAllControlsOfType<T>(this Control parent) where T : Control
{
var result = new List<T>();
foreach (Control control in parent.Controls)
{
if (control is T)
{
result.Add((T)control);
}
if (control.HasControls())
{
result.AddRange(control.GetAllControlsOfType<T>());
}
}
return result;
}
}
From Database:
Get All Actions IDs (like divAction1,divAction2 ....) dynamic in DATASET (DTActions) allow on specific User.
In Aspx:
in HTML Put Action(button,anchor etc) in div or span and give them id like
<div id="divAction1" visible="false" runat="server" clientidmode="Static">
<a id="anchorAction" runat="server">Submit
</a>
</div>
IN CS:
Use this function on your page:
private void ShowHideActions()
{
var controls = Page.GetAllControlsOfType<HtmlGenericControl>();
foreach (DataRow dr in DTActions.Rows)
{
foreach (Control cont in controls)
{
if (cont.ClientID == "divAction" + dr["ActionID"].ToString())
{
cont.Visible = true;
}
}
}
}
Recursively find all controls matching the specified predicate (do not include root Control):
public static IEnumerable<Control> FindControlsRecursive(this Control control, Func<Control, bool> predicate)
{
var results = new List<Control>();
foreach (Control child in control.Controls)
{
if (predicate(child))
{
results.Add(child);
}
results.AddRange(child.FindControlsRecursive(predicate));
}
return results;
}
Usage:
myControl.FindControlsRecursive(c => c.ID == "findThisID");
I decided to just build controls dictionaries. Harder to maintain, might run faster than the recursive FindControl().
protected void Page_Load(object sender, EventArgs e)
{
this.BuildControlDics();
}
private void BuildControlDics()
{
_Divs = new Dictionary<MyEnum, HtmlContainerControl>();
_Divs.Add(MyEnum.One, this.divOne);
_Divs.Add(MyEnum.Two, this.divTwo);
_Divs.Add(MyEnum.Three, this.divThree);
}
And before I get down-thumbs for not answering the OP's question...
Q: Now, my question is that is there any other way/solution to find the nested control in ASP.NET?
A: Yes, avoid the need to search for them in the first place. Why search for things you already know are there? Better to build a system allowing reference of known objects.
https://blog.codinghorror.com/recursive-pagefindcontrol/
Page.FindControl("DataList1:_ctl0:TextBox3");
OR
private Control FindControlRecursive(Control root, string id)
{
if (root.ID == id)
{
return root;
}
foreach (Control c in root.Controls)
{
Control t = FindControlRecursive(c, id);
if (t != null)
{
return t;
}
}
return null;
}
The following example defines a Button1_Click event handler. When invoked, this handler uses the FindControl method to locate a control with an ID property of TextBox2 on the containing page. If the control is found, its parent is determined using the Parent property and the parent control's ID is written to the page. If TextBox2 is not found, "Control Not Found" is written to the page.
private void Button1_Click(object sender, EventArgs MyEventArgs)
{
// Find control on page.
Control myControl1 = FindControl("TextBox2");
if(myControl1!=null)
{
// Get control's parent.
Control myControl2 = myControl1.Parent;
Response.Write("Parent of the text box is : " + myControl2.ID);
}
else
{
Response.Write("Control not found");
}
}