Retrieve the control's name

Islorvat

Hello! I'm working on an application wich will alow the user to add and remove controls. I want to apply different rules to textbox and this rules will be different for every textbox. For example i want to check wich control has been clicked by using a click event. Because i don't know how many textboxes will the user create i've decided to go along with the code below:

    private void Form1\_Load(object sender, EventArgs e)
    {
        foreach (Control ctrl in Controls)
        {
            ctrl.Click += new EventHandler(ctrl\_Click);
        }
    }

    void ctrl\_Click(object sender, EventArgs e)
    {

    }

Is there anyway that i can get the name of the control that has been clicked? The sender.Tostring() only returns the type and the text of the control. Thanks! ;)

Rob Philpott

Yes, what you want to do is cast the sender to a Control such:

void ctrl_Click(object sender, EventArgs e)
{
Control contol = sender as Control;

if (control != null)
{
    string name = control.Name;
}

}

Regards, Rob Philpott.

c0ax_lx

Hi. void ctrl_Click(object sender, EventArgs e) { if (sender.GetType() == typeof(TextBox)) { string name = ((TextBox)sender).Name; } } should work. Also if you are only interested in handling clicks for textboxes you could change the foreach loop to: foreach (Control ctrl in Controls) { if (ctrl.GetType() == typeof(TextBox)) { ctrl.Click += new EventHandler(ctrl_Click); } }

If it' stuck, DO NOT pull harder!

Luc Pattyn

do NOT compare strings to check for a type, instead use the appropriate keywords: do NOT compare types, nor strings representing types, instead use the appropriate keywords:

if (sender is TextBox) log("this is a TextBox");
// or
TextBox tb=sender as TextBox;
if (tb!=null) log("this is a TextBox");

it is both faster and more correct as it also matches derived types. :)

Luc Pattyn [Forum Guidelines] [My Articles]

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

modified on Saturday, November 28, 2009 7:37 AM

c0ax_lx · modified on Saturday, November 28, 2009 7:37 AM

According to MSDN help -GetType and typeof returns System.Type, i totally agree with "if (sender is TextBox)". A humble question, do you mean that GetType()==typeof compiles as a string comparizon? else i dont understand the "do NOT compare strings to check for a type, instead use the appropriate keywords"

If it' stuck, DO NOT pull harder!

Luc Pattyn

Sorry, I should have said "do NOT compare types, nor strings representing types, to check for a type, ..." is/as are more efficient than GetType constructs :)

Luc Pattyn [Forum Guidelines] [My Articles]

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

c0ax_lx

ok! Thanks Luc, for a split second i thought you were wrong, i should have known better ;)

If it' stuck, DO NOT pull harder!

PIEBALDconsult

Ah, now that's signature material! :-D

Luc Pattyn

:thumbsup:

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

BillWoodruff

Some ideas that may (I hope) bear on your solution : Is it the case that any TextBoxes are inside containers within the Form (nested) : in that case you are going to need to recurse to find them and attach an Event Handler. Unfortunately to get the Form.ControlCollection into a "flattened" IEnumerable where you can do cool filtering with Linq, and just, for example, pull out all the TextBoxes into a nice List<>, takes some voodoo which I am just now exploring myself, so am reluctant to comment on that so far. If TextBoxes are the only controls you want to put a special Event handler on, it seems like overkill to add a subscriber to the 'Click event of every control on your Form or whatever (unless, of course, they are all TextBoxes).

        foreach (Control candidate in Controls)
        {
            if(candidate is TextBox) // assign your event handler here
        }

The TextBox does expose an 'Enter event, and when that event is fired, you can be sure that the 'sender parameter inside that event is also the same as your MainForm.ActiveControl. That might be something you could exploit. If you are maintaining an arbitrary collection of TextBox controls which the end-user has the power to create and/or remove, you might consider keeping a List<TextBox> up to date, and, possibly a TextBox currentTextBox variable: these may come in handy. Assuming by "apply different rules to TextBoxes" you mean execute some code for one class of TextBoxes, and execute different code another class of TextBox you could consider a Dictionary of <TextBox, Action<Control>> as found in the very interesting answer by Nathan W. here : [^] which uses recursion in a very clever way. best, Bill

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