Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

MaskedTextBox - TextChanged Event Throws Error

Posted on 2012-03-28
6
Medium Priority
?
917 Views
Last Modified: 2012-03-28
Using VB.Net 2010 (Pro)

I hav a form which contains several standard text boxes and a few MaskedTextBox controls I use for date input (ie set mask format to short date).

I want to know when the form becomes "dirty", so I've put code to check the values in the text boxes against the original data.  This has worked fine for standard text boxes, which I put code in the "TextChanged" event to test for "dirty".  For that standard textboxes, I've combined the "TextChanged" handler into one single routine.

However, when I try the same thing for a MaskedTextBox, when starting the application it immediately throws an error that reads:
Value cannot be null
All I have done to get this error is add the "TextChanged" event,  I have not yet even put code in the event.

I have tried both having a seperate handler, as well as combining it with the standard TextBox handlers.  Both fail with the same error.

What's going on and, more importantly, how go I get it to work?

TIA
0
Comment
Question by:Clif
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 5

Expert Comment

by:Rainverse
ID: 37776776
I do not believe the .Net maskedtextbox supports null values. In other words, it has to have a default value to begin with and compare to when the value is changed.

-MJC
0
 
LVL 10

Author Comment

by:Clif
ID: 37776831
That explains the problem but doesn't offer a solution.
0
 
LVL 5

Expert Comment

by:Rainverse
ID: 37776977
Give it a default value. Any date will do. It just won't validate against a Null value.  (i.e. does myDate = Null)

-MJC
0
Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

 
LVL 16

Accepted Solution

by:
Rose Babu earned 2000 total points
ID: 37776978
instead of "TextChanged" event can you use "Leave" event of a "MaskedTextBox "? then test the application once.
0
 
LVL 10

Author Comment

by:Clif
ID: 37777129
Rainverse,

I can't put a default date, if there is no date to put (ie, it's not a financed vehicle, so there is no Payoff date).  Putting an arbitrary date in would be confusng to the user.

This is the reason I went with the MaskedTextBox instead of the DateTimePicker.
0
 
LVL 10

Author Closing Comment

by:Clif
ID: 37777149
The Leave event seems to work as I need.

Thanks.  :)
0

Featured Post

New feature and membership benefit!

New feature! Upgrade and increase expert visibility of your issues with Priority Questions.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Since .Net 2.0, Visual Basic has made it easy to create a splash screen and set it via the "Splash Screen" drop down in the Project Properties.  A splash screen set in this manner is automatically created, displayed and closed by the framework itsel…
Creating an analog clock UserControl seems fairly straight forward.  It is, after all, essentially just a circle with several lines in it!  Two common approaches for rendering an analog clock typically involve either manually calculating points with…
In this brief tutorial Pawel from AdRem Software explains how you can quickly find out which services are running on your network, or what are the IP addresses of servers responsible for each service. Software used is freeware NetCrunch Tools (https…
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…

721 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question