[AN1554]

If txtbox.Text <> "" Then txtbox.Text = ""

Or

txtbox.Text = ""

?

Is it better to just erase the text of a textbox or first check if it is not empty then erase it if it is not? Does the IF add to overheads?

This post has been edited by AN1554: 28 April 2012 - 12:27 PM

[Neku]

depened.. what if it hold something you dont want to delete?

[AN1554]

The question is whether IF adds to overheads.

This post has been edited by AN1554: 28 April 2012 - 12:27 PM

[Neku]

i guess it will take 1 or 2 extra cycles from the computer but again its really depened why you do this.
if its simply to reset a form its logical to just do

Textbox.Text = ""

but if it hold some data you want to keep its cheaper not to touch it than transfering the data to a variable and then back to the textbox.

[BobRodes]

AN is asking whether it's more overhead to set a text box to empty if it is already empty, or more to check first to see if it's empty. The answer is yes, IF adds to overhead, although the overhead is negligible. Evaluating a condition requires processor instructions to be run.

Also, you have to access the objects property whether you get it or set it, and this requires overhead too--more than a condition evaluation. So the greatest overhead is in referencing the property. Getting vs setting the property is about equal. Therefore, you incur double overhead each time you use the if statement, because you are referencing the property twice instead of once.

So, just set it to "".

This post has been edited by BobRodes: 30 April 2012 - 07:34 AM

[Neku]

i know that this is what he asked but what if the textbox is not empty? "

This post has been edited by Neku: 30 April 2012 - 07:36 AM

[BobRodes]

The answer to your question is that the code should empty it! He's not interested in the condition that you mention, "if it holds some data that you want to keep".

Look at his code. He's saying if the text box is not empty, then empty it. Or should he just empty it without checking, thereby having the possibility of a code redundancy by emptying an already empty text box.

A practical example would be:

Sub ClearTextBoxes()
For each tBox in Controls
    If TypeOf tBox Is TextBox Then
        tBox.Text = ""
    End If
Next

' Or:

For each tBox in Controls
    If TypeOf tBox is TextBox Then
        If tBox.Text <> "" Then
            tBox.Text = ""
        End If
    End If
Next

He's just asking which bit of code is more efficient in terms of performance.

And AN, by the way, this iterating through all the controls and checking to see if the type is a text box is the standard way of doing it, even though it has the inefficiency of checking each control including those that are not text boxes.