How to get Active TextBox Windows Forms

Question

I have 2 textboxes in the form textbox1 and textbox2 (Yeah was pretty lazy) and the task of creating a copy and paste like function for the application (for practice reasons)

but I have no idea how the program will determine which textbox is currently the active one

    public partial class Form1 : Form
    {

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.F1) //Copy
        {

        }
        else if (e.KeyCode == Keys.F2) //Paste
        {

        }
    }
}

Alex · Answer 1 · 2016-06-29T05:54:27.357

0

You have to cast the sender to a TextBox and get its name or whatever identifies your textboxes. Do it responsibly, use as : var textBox = sender as TextBox and then check it for null

EDIT: the event handler must be assigned to both TextBoxelements not to the form

edited Jun 29 '16 at 05:54

answered Jun 28 '16 at 14:22

Alex

3,689
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do I have to do it for each of my textboxes?... – Kennedy del Rosario Jun 28 '16 at 14:29
1

This will only work if that `KeyDown` handler is assigned to the `TextBox`es' `KeyDown` events. From it's name I thought it's assigned to the `Form`'s event, so `sender` is always the `Form`, not the `TextBox`. – René Vogt Jun 28 '16 at 14:31
@kennedydelrosario yeah, you have to asign this event to each `TextBox` – Alex Jun 29 '16 at 05:53

score 0 · Answer 2 · edited May 23 '17 at 12:08

0

Possibly you have a question already got an answer.

Form.ActiveControl may be what you want.

edited May 23 '17 at 12:08

Community

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answered Jun 28 '16 at 14:25

Shiv

129
2
10

score 0 · Answer 3 · answered Jun 28 '16 at 14:25

You can determine which TextBox is activated by using the ContainsFocus property:

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    TextBox activeTextBox = textBox1.ContainsFocus 
                    ? textBox1
                    : (textBox2.ContainsFocus ? textBox2 : null);     

    if (e.KeyCode == Keys.F1) //Copy
    {

    }
    else if (e.KeyCode == Keys.F2) //Paste
    {

    }
}

Or alternatively the Form.ActiveControl property:

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    TextBox activeTextBox = ActiveControl as TextBox;

    if (e.KeyCode == Keys.F1) //Copy
    {

    }
    else if (e.KeyCode == Keys.F2) //Paste
    {

    }
}

How to get Active TextBox Windows Forms

3 Answers3