Fire events manually

Question

I have some controls on my form to which I assigned (via designer) functions to the Leave envent, something like this:

textBox1.Leave += new System.EventHandler(f1);
textBox2.Leave += new System.EventHandler(f2);
textBox3.Leave += new System.EventHandler(f3);

These functions perform some validation on the textboxes. Note that not all the textboxes call the same delegate.

What I need now is to be able to tell them "hey, fire the Leave event" when I want. On my case I call this function somewhere at start:

private void validateTextBoxes()
{
    foreach (Control c in c.Controls)
    {
        TextBox tb = c as TextBox;
        if (tb != null)
        {
            // Fire the tb.Leave event to check values
        }
    }
}

So every textbox validates with its own code.

Answer 1

I presume you dont really want to fire the Leave event you just want to validate the textbox in the same way the leave event would, why not just run them both through the same validation method..

private void ValidateTextBox(TextBox textBox)
{
    //Validate your textbox here..
}

private void TextBox_Leave(object sender,EventArgs e)
{
    var textbox = sender as TextBox;
    if (textbox !=null)
    {
        ValidateTextBox(textbox);
    } 
}

then wire up the leave event

textBox1.Leave += new System.EventHandler(TextBox_Leave);
textBox2.Leave += new System.EventHandler(TextBox_Leave);
textBox3.Leave += new System.EventHandler(TextBox_Leave);

then your initial validation code.

private void validateTextBoxes()
{
    foreach (Control c in c.Controls)
    {
        TextBox tb = c as TextBox;
        if (tb != null)
        {
            // No need to fire leave event 
            //just call ValidateTextBox with our textbox
            ValidateTextBox(tb);
        }
    }
}

Answer 2

As an alternative to your current approach, you might want to consider using the Validating event instead, which is precisely for this kind of thing.

If you use Validating, you can then use ContainerControl.ValidateChildren() to perform the validation logic for all the child controls. Note that the Form class implements ValidateChildren().

Personally, I think that's what you should be doing.