How to declare an optional textbox in a sub routine in vb.net

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Dear Friends

I want to make a sub routine with some optional controls like Textbox and combobox. My sample sub routine is as under;

VB

Private Sub ActivateControls(rd As RadioButton, Optional  txt As TextBox)


End Sub

But when I wrote this sub routine Vb.Net IDE gives me the error that each Optional Parameter must specify a default value. So, here I cant understand that what can be the default value of a textbox.

If any body can help me, I will be grateful.

By

Rashid Farooq

Posted 27-Jul-10 6:56am

rashidfarooq

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William Winner 27-Jul-10 15:03pm

Reason for my vote of 1
pretty basic google search

3 solutions

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AnnieMacD · Answer 1 · 2010-07-27T11:41:00

Solution 2

Optional arguments do need to be initialized so you could set it to Nothing.

VB

Private Sub ActivateControls(rd As RadioButton, Optional  txt As TextBox = Nothing)


End Sub

Posted 27-Jul-10 11:41am

AnnieMacD

Yusuf · Answer 2 · 2010-07-27T07:30:00

Solution 1

VB Optional Arguments[^]

Posted 27-Jul-10 7:30am

Yusuf

rashidfarooq · Answer 3 · 2010-07-28T03:26:00

Thanks for Answering Brother.
Your answer does work.
But when I make a the subroutine with a default value of Nothing and when I run the program it runs correctly only if i gave all the arguments including optional values. If i miss only one optional argument it gives the error that Object Reference not set to an instance of object.
Here is my subroutine.

VB

Private Sub ActivateControls(rd As RadioButton, Optional  txt As TextBox = Nothing, txt2 As TextBox = Nothing)
End Sub

When I called this subroutine in my program as

ActivateControls(rdbtn,txt)

It gives me the following error

"Object Reference not set to an Instance of an Object"

But when I write this subroutine as

ActivateControls(rdbtn,txt,txt2)

It works right.

So, Please tell me what is the solution of this problem.

OR

Is there any other value Except Nothing That I can set as Default value of Optional controls(like textbox, combobox)