How I find: What is focused.

Question

Hello:

Is there a service/control/whatever that can be running in a program and let me know what is focused?

Reason is: I would like to have something running that can update the statusBar with what is Focused. I know I can put code for each object on Enter and on Leave. But I have many objects and I hate to put so much redundant code in the program. Also I would like to write a routine that validates the field that is just left and go to the validation routine and if invalid go back to the field. Am I dreaming, too much?

Sam Hobbs · Answer

The following is not exactly what you need but I hope it is close enough. public Form1() { InitializeComponent(); Control c = GetNextControl(null true); while (c != null) { if (c.GetType().Name == TextBox) c.Enter += new EventHandler(Controls_Enter); c = GetNextControl(c true); } } private void Controls_Enter(object sender EventArgs e) { Control c = sender as Control; if (c == null) return; toolStripStatusLabel1.Text = c.Text; }

Sam Hobbs · Answer

Note that the controls in the Controls property includes nested controls. You can get the controls of the form without also getting nested controls by using the GetNextControl method. You could do that in the form load event and assign events such as Enter and Leave to each control. You might need to add exceptions such as ignoring menus (maybe) but otherwise you can handle most or all controls using a single events handler. I suggest not doing that for the validation part; I think validation should be customized for each control. Control c = GetNextControl(null true); while (c != null) { c = GetNextControl(c true); } Another option is to use an Application . Idle Event for the form and in the event use the ActiveControl property. That might not work if there are multiple forms unless you include code to deal with that. I think if you add an idle event handler for a form it will be executed for all forms so that might be too advanced for you if you are not familiar with Windows enough.

Sam Hobbs · Answer

The c.GetType().Name == TextBox just filters the controls so that all other controls are ignored for this. It is a sample; you can adjust as you need to. Just look at the Control class; I think the Name property is what you are looking for. But maybe it is not; you probably want the label not the name and that is not as easy. What I might do is to use the Tag property as in textbox1.Tag. I would set it to the label control that has the field title in so I could get the value dynamically. Try to figure that out on your own.

Gustavo · Answer

Sam: For testing I took out the: if (c.GetType().Name == TextBox). So it would tell me what all of 'c' is. I will surf and try to find more info on it to see what else I can pull out of it. Thanks

Sam Hobbs · Answer

I don't understand why you say it shows: System.Windows.Forms.textBox Text: Perhaps you are saying that because that is what you are putting out in your code. To see what else you can put out just look at the members of the Control class or whatever the relevant class is. Did you try that?

Gustavo · Answer

Sam: Thanks... Now I see how it works...It cooool. It shows: System.Windows.Forms.textBox Text: Is there a way I can get back the name of the text box?

Gustavo · Answer

Sam: Nope I dont. Is it simple to learn?

Sam Hobbs · Answer

Do you know how to add event handlers to controls?

Gustavo · Answer

Sam: I put it where you wanted me to... but How do I use it? I wanted the value of what is focused to go to: toolStripStatusLabelHint.Text = _______;

Sam Hobbs · Answer

It should work to put the code in the form constructor after the call of InitializeComponent(). InitializeComponent creates the controls and adds event handlers so your code would do a little more of the same.

Gustavo · Answer

Sam: I will try it out. Not sure where to actually put it. But It will give me something to play with.

Hirendra Sisodiya · Answer

Do you want to know that which control is focused if yes you can apply this code on neccessary place: foreach (Windows.Forms.Control obj in this .Controls) { if (obj.Focused) { } //obj is focused } if you want to know another thinglet me know thanks