I have a Placeholder and I have a dynamically created panel in the placeholder, I also have some dynamically added radio buttons in the panel, now I can usefindControl() to find the radio buttons if they are direct children of the placeholder.
I've literally spent the whole of yesterday trying to find them when they are the child elements of the Panel. How is there a way to do this?
Here's my code below:
PlaceHolder1.Controls.Add(myPanel); //add the panel to the placeholderenter code here
myPanel.Controls.Add(myRadioButton); //add the radiobutton to the panel
You should make method that recursively searches for a control using it's Id. That mean that the method will search for a control inside of (in your case) placeholder. If method finds control, it will return it. If not, it will go search every placeholder's subcontrol, going "deeper". And then, if nothing is found, it will search one more level down, in every placeholder subcontrols' subcontrol etc.)
private Control FindControl(string ctlToFindId, Control parentControl)
{
foreach (Control ctl in parentControl.Controls)
{
if (ctl.Id == ctlToFindId)
return ctl;
}
if (ctl.Controls != null)
{
var c = FindControl(ctlToFindId, ctl);
if (c != null) return c;
}
return null;
}
and then use it like this:
Control ctlToFind = FindControl(myRadioButton.Id, Placeholder1);
if (ctlToFind != null)
{
//your radibutton is found, do your stuff here
}
else
{
// not found :(
}
Finding Controls recursive is an option, but it also has a couple of down-sides.
If you know the ID's of all the controls you can just use FindControl
RadioButtonList myRadioButton = PlaceHolder1.FindControl("Panel1").FindControl("RadioButtonList1") as RadioButtonList;
Label1.Text = myRadioButton.SelectedValue;
But you will need to give your dynamically added controls an ID.
Panel myPanel = new Panel();
myPanel.ID = "Panel1";
RadioButtonList myRadioButton = new RadioButtonList();
myRadioButton.ID = "RadioButtonList1";
PlaceHolder1.Controls.Add(myPanel);
myPanel.Controls.Add(myRadioButton);
Related
I'm using a custom Button which contains other elements and color styles like TopColor and BotColor. I need to handle this Button inside a panel with other panels.
I'm trying this:
foreach(CustomButton btn in panel1.Controls)
{
if(btn is CustomButton)
{
btn.TopColor=Color.Red;
}
Inside panel1 I'm containing other panels too. And the error I'm getting is
it can't be conversion element panel in a button.
One solution is to separate buttons in one panel. But I want to ask if there is some way to avoid other elements. The reason I don't want to use foreach (Control a in this.Controls) is it doesn't recognise my custom color style TopColor and BotColor
Take a look
Loop through all your controls (as Controls), check if it's a button, then cast it before you try and set the colour.
foreach(Control c in panel1.Controls)
{
if (c is CustomButton)
{
(c as CustomButton).TopColor = Color.Red;
}
}
I hope this solution works for you.
private void SetStylesToCustomButtons(Control.ControlCollection controls)
{
foreach (Control control in controls)
{
if (control is CustomButton)
{
(control as CustomButton).TopColor = Color.Red;
}
else if (control is Panel)
{
SetStylesToCustomButtons((control as Panel).Controls);
}
}
}
The reason you're getting an error is that you're trying to cast all your controls to CustomButton, even the panels. You already know the type that you're looking for, so you don't have to loop through every control in your panel.
Assuming all your custom buttons are in panel1 and that you don't need to recurse, you should rather filter the items down to the type that you want and then work with them:
var customButtons = panel1.Controls.OfType<CustomButton>();
foreach (CustomButton customButton in customButtons)
{
//do what you need here
}
I know about the FindControl BUT my button is inside a Login control which is inside a LoginView control,below is my code but its not working!!
Login log = LoginView1.FindControl("Login1") as Login;
Button logButton = log.FindControl("LoginButton") as Button;
this.Form.DefaultButton = logButton.UniqueID;
Th error I get is
Object reference not set to an instance of an object.
FindControl only looks at the immediate children. You'd need to recursively navigate all the children, the children's children, etc., to find the control you're looking for.
public Control MyFindControl(Control parent, string controlIdToFind)
{
foreach(Control c in parent.Controls)
{
Control found = MyFindControl(c, controlIdToFind);
if (found != null)
{
return found;
}
}
// control not found.
return null;
}
Then change your code to:
Button logButton = (Button) MyFindControl(LoginView1, "LoginButton");
if (logButton != null)
{
this.Form.DefaultButton = logButton.UniqueID;
}
I have tons of Buttons named like this x0y1
How do I access the variable name dynamically so I could loop all names by xiy1 or so.
in PHP it would be like ${"myString" . $randomvar}
I can't use a list or array because the the button already exist defined through the xaml
You can use:
var textbox =
this.Controls.OfType<TextBox>().Where(txb => txb.Name == "myString").FirstOrDefault();
This assumes you are in the context of your form (this.Controls).
And of course, don't forget to add using System.Linq;...
You can get all the textbox using this method
void AllTextBox(System.Windows.Forms.Control.ControlCollection ctrls)
{
foreach (Control ctrl in ctrls)
{
if (ctrl is TextBox)
{
if (ctrl.Name == "textBox1")
{
// do your stuf with textbox
}
}
}
}
You can create function that return control by name :
Control GetControlByName(string Name)
{
foreach(Control control in this.Controls)
if(c.Name == Name) return control ;
return null;
}
or Function with a specific control like that :
Button GetButtonByName(string Name)
{
foreach (Control c in this.Controls.OfType<Button>())
if (c.Name == Name) return c;
return null;
}
For wpf project...
Let's say you have a grid named MyGrid and there's lot of buttons on it.
You want to refer to the button named x0y1:
var btn = MyGrid.Children.OfType<Button>().Where(x=>x.Name=="x0y1");
Note: above code should work for flat structure (one level deep only).
You can achieve the same by using code provided in this thread: How can I find WPF controls by name or type?
Just call FindName("elementName"). FindName searches through all child elements of a FrameworkElement. To access any button by its name as string in a window, call the FindName() method of the window !
If your code is in a class inheriting from Window, just use:
Button button = (Button)FindName("xiy1");
If you write the code in a class not inheriting from Window but FrameworkElement, which is unlikely, use:
Window window = Window.GetWindow(this);
Button button = (Button)window.FindName("xiy1");
Check the MSDN documentation about Namescopes for more information about limitations.
I am working on an application that has a GridView item on an ASP.net page which is dynamically generated and does a partial post-back as items are updated within the grid-view. This partial post-back is causing the tab indices to be lost or at the very least ignored as the tab order appears to restart. The grid view itself already has the pre-render that is being caught to calculate the new values from the modified items in the grid-view. Is there a way to get what element had the focus of the page prior to the pre-render call? The sender object is the grid-view itself.
You can try using this function, which will return the control that caused the postback. With this, you should be able to reselect it, or find the next tab index.
private Control GetControlThatCausedPostBack(Page page)
{
//initialize a control and set it to null
Control ctrl = null;
//get the event target name and find the control
string ctrlName = Page.Request.Params.Get("__EVENTTARGET");
if (!String.IsNullOrEmpty(ctrlName))
ctrl = page.FindControl(ctrlName);
//return the control to the calling method
return ctrl;
}
Here's an instance where I had dynamically generated inputs that updated totals via AJAX on change. I used this code to determine the next tab index, based on the tab index of the control that caused the postback. Obviously, this code is tailored to my usage, but with some adjustments I think it could work for you as well.
int currentTabIndex = 1;
WebControl postBackCtrl = (WebControl)GetControlThatCausedPostBack(Page);
foreach (PlaceHolder plcHolderCtrl in pnlWorkOrderActuals.Controls.OfType<PlaceHolder>())
{
foreach (GuardActualHours entryCtrl in plcHolderCtrl.Controls.OfType<GuardActualHours>())
{
foreach (Control childCtrl in entryCtrl.Controls.OfType<Panel>())
{
if (childCtrl.Visible)
{
foreach (RadDateInput dateInput in childCtrl.Controls.OfType<RadDateInput>())
{
dateInput.TabIndex = (short)currentTabIndex;
if (postBackCtrl != null)
{
if (dateInput.TabIndex == postBackCtrl.TabIndex + 1)
dateInput.Focus();
}
currentTabIndex++;
}
}
}
}
}
I have seen many others with similar problems but I cannot find the flaw in my logic here. Any help would be greatly appreciated.
I have a Panel which I have added numerous label and textbox controls to, ie:
myPanel.Controls.Add(txtBox);
These controls are created and added in a method called previous to the iteration method.
I want to iterate through each textbox and use its Text property as a parameter in another method but I am not having any luck. Here is my attempt to iterate:
public void updateQuestions()
{
try
{
foreach (Control c in editQuestionsPanel.Controls)
{
if (c is TextBox)
{
TextBox questionTextBox = (TextBox)c;
string question = questionTextBox.Text;
writeNewQuestionToTblQuestions(question);
}
}
}
catch (Exception err)
{
Console.WriteLine(err.Message);
}
}
The problem I am having is that the controls are not in the Panel when I arrive at this updateQuestions() method. Here is the process involved:
A commandButton is clicked and the questions are read from a DB, for each question a method is called which adds 2 labels and a textbox to editQuestionsPanel.Controls. This panel is inside a PlaceHolder which is then made visible.
When a button inside the PlaceHolder is clicked, the updateQuestions() method is called and the editQuestionsPanel.Controls.Count = 1. As there are approx 12 questions in the DB it should be around 36. The one control inside the Panel is of type:
System.Web.UI.LiteralControl
It contains no controls.
I am sure that somwhere in the lifecycle the Panel's controls are being cleared but I do not know how to step thru the life cycle. I have a Page_load method which is called as soon as a button is clicked but once the button which calls updateQuestions() is clicked the editQuestionsPanel.Controls.Count is already back to 1 so it must be cleared before this but I do not know how to correct this...
Any help you can give to help me solve this would be greatly appreciated - its killing me!
This selects from collection controls only that which are of type TextBox.
(the same as control is TextBox or (control as TextBox) != null)
If controls are contained in editQuestionsPanel.Controls:
using System.Linq;
IEnumerable<TextBox> textBoxes = editQuestionsPanel.Controls.OfType<TextBox>();
foreach (TextBox textBox in textBoxes)
{
// do stuff
}
To select all child controls use next extension method:
public static IEnumerable<T> GetChildControls<T>(this Control control) where T : Control
{
var children = control.Controls.OfType<T>();
return children.SelectMany(c => GetChildControls<T>(c)).Concat(children);
}
Using:
IEnumerable<TextBox> textBoxes = editQuestionsPanel.GetChildControls<TextBox>();
When you add controls dynamically, you need to do that on every request - asp.net doesn't do that for you!
Add the controls in the Init or Load phase, then they will get populated with the postback values.
A frequently made mistake: Container.Controls only contains the first level child controls in this container. That is: TextBox1 in PanelA, PanelA in PanelB, you can't get TextBox1 in PanelB.Controls.
My solution is to write an extension method:
public static IEnumerable<Control> AllControls(this Control ctl)
{
List<Control> collection = new List<Control>();
if (ctl.HasControls())
{
foreach (Control c in ctl.Controls)
{
collection.Add(c);
collection = collection.Concat(c.AllControls()).ToList();
}
}
return collection;
}
Now TextBox1 is in PanelB.AllControls(). To filter all controls with type, using PanelB.AllControls().OfType<TextBox>()
If the other answers don't help, try doing your code but add recursivity. Your code would not work if it's editQuestionsPanel => Panel => Textbox
You can do something like this instead:
var questions = from tb in editQuestionsPanel.Controls.OfType<TextBox>()
select tb.Text;
foreach(var question in questions)
{
writeNewQuestionToTblQuestions(question);
}
Try this
int Count = 0;
foreach (Control ctr in Panel1.Controls)
{
if (ctr is TextBox)
Count++;
}