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Posted 11 Apr 2005


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Validators for Windows Forms - ValidationProvider Control

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16 Apr 20053 min read
Code-free validation for TextBox, ComboBox, and more...

Image 1


Do you spend most of your time writing custom validations on Windows Forms? Have you ever wanted an equivalent WinForm validator like in WebForm? Noogen ValidationProvider can help you speed up your WinForms design time by providing powerful, easy and virtually code-free wiring of input validations.


For the beginners, I would suggest a reading of Paul Riley's article on Validators in ASP.NET/WebForms - ASP.NET Validators Unclouded. This is because ValidationProvider engine is derived from WebForm Validators base.

Noogen ValidationProvider is also built on ErrorProvider, see the article by Naveen K. Kohli - How To Use The ErrorProvider Object To Indicate Invalid Control State.

I know that this topic has been discussed many times (example MSDN article - Extending Windows Forms with a Custom Validation Component Library, Part 3), but most of the articles I've seen are either too restricted to a single control (TextBox) or too complicated. My goal with Noogen ValidationProvider is to bring all these great ideas together and simplify them.

The design

  1. To speed up development, Noogen ValidationProvider re-uses WebForm validator base engine and displays error using ErrorProvider Control (hence the name ValidationProvider).
  2. My second goal is to provide easy wiring of basic/familiar validations as seen in WebForm, which includes: DataTypes check, required field, range and value comparison validations, and more...
  3. Noogen ValidationProvider also tests and validates regular expressions and can even wire more advance custom validations.

I'll stop here before I go too far off from the topic. Of course, if you wish to drill down on the details, all the source codes are provided.

Using the code

Basic Validations

ValidationProvider makes it easy to setup validation for TextBox and ComboBox controls. You don't have to write a single line of code. Just compile the accompanied source in release mode, browse and add it to your VS.NET IDE ToolBox, drop it on the form, and you are ready to visually design your input validations.

Image 2

ValidationProvider property exposes Edit ValidationRules link/verb on the "Properties Window". I have also implemented IExtenderProvider to enable easy editing of specific ValidationRule ties to individual TextBox or ComboBox controls.

The only code you will need is given below:

// Call Noogen ValidationProvider public method - 
// Validate() and display error if returns false.

Public Methods

CanExtendDetermine if the ValidationProvider supports a component.
GetIconAlignmentGet Error Icon alignment.
GetIconPaddingGet Error Icon padding.
GetValidationRuleGet validation rule.
SetIconAlignmentSet Error Icon alignment.
SetIconPaddingSet Error Icon padding.
SetValidationRuleSet validation rule.
ValidateOverloaded. Perform validation on all controls.
ValidationMessagesGet validation error messages.

Regular expression validations

Image 3

ValidationProvider can test and validate regular expressions (RegEx). For your convenience, a RegEx test bench is provided. RegEx test value applies the same validation engine, and the data gets validated as you type in. You can wire some very powerful and advance validations with RegEx. With creativity, I believe that you can virtually use it in place of all the Basic Validations, but RegEx can be complicated to derive. Thus, you would probably use RegEx validation as an accommodation to the provided Basic Validations. The demo application demonstrates simple email and data length Regular Expression validations.

If you've worked with regular expressions before, then you would have probably collected some favorite RegEx patterns. ValidationProvider allows you to load your collection RegEx patterns so that you can re-use it consistently and share it with your developer friends. You would simply edit and add your RegEx collection to the accompanied file "RegExPatternStore.xml" as seen in the animation above.

Custom Validations

OK, I lied! The above code is not the only code you will need. When business logic gets complicated or if it is required to validate controls that the ValidationProvider does not support, custom validation methods can be wired onto ValidationProvider like this:

// Create new ValidationRule and wire-up custom validation method.  
// This can be somewhere in the ctor.
Noogen.Validation.ValidationRule vr = new Noogen.Validation.ValidationRule();
vr.CustomValidationMethod += 
 new Noogen.Validation.CustomValidationEventHandler(vr_CustomValidationMethod);
this.validationProvider1.SetValidationRule(this.textBox6, vr);
// The custom validation method.
private void vr_CustomValidationMethod(object sender, 
                 Noogen.Validation.CustomValidationEventArgs e)
   e.IsValid = 
        e.Value.ToString().Equals("abc") || e.Value.ToString().Equals("123") ;
   e.ErrorMessage = "%ControlName% is not in ('abc', '123').";

Point of interest

For the purpose of demonstration, I have put both the Noogen.Validation.Design and ValidationProvider in a single project. You would probably want to name your build of ValidationProvider to separate the Designer from the Provider. This will reduce the assembly size, since the Designer is not required for deployment.


  • April 11th, 2005 - ValidationProvider 1.0 posted.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

Written By
Web Developer
United States United States
If at first you don't succeed, refract and refract again...

Comments and Discussions

QuestionHow to add an option to use with other input controls? Pin
marcelo2319-Jul-08 8:39
Membermarcelo2319-Jul-08 8:39 
GeneralI need some help Pin
Laco424-Mar-08 10:45
MemberLaco424-Mar-08 10:45 
GeneralThank you Pin
Jecho Jekov27-Dec-07 11:48
MemberJecho Jekov27-Dec-07 11:48 
GeneralFocus on First invalid Field Pin
Nic Roche12-Apr-07 16:19
MemberNic Roche12-Apr-07 16:19 
GeneralRe: Focus on First invalid Field Pin
DiJ85-Jul-09 13:32
MemberDiJ85-Jul-09 13:32 
GeneralRe: Focus on First invalid Field Pin
keshav120125-Mar-13 21:45
Memberkeshav120125-Mar-13 21:45 
Questionmaskedtextbox Pin
pikey12328-Mar-07 10:31
Memberpikey12328-Mar-07 10:31 
GeneralCustom Validations - help Pin
rontubi3-Dec-06 2:17
Memberrontubi3-Dec-06 2:17 
GeneralOutstanding Pin
phimix28-Nov-06 0:33
Memberphimix28-Nov-06 0:33 
QuestionDataTypeCheck and RequiredField Pin
kaelaa13-Nov-06 9:07
Memberkaelaa13-Nov-06 9:07 
AnswerRe: DataTypeCheck and RequiredField Pin
youbest.cn10-Dec-06 15:27
Memberyoubest.cn10-Dec-06 15:27 
GeneralRe: DataTypeCheck and RequiredField Pin
DiJ85-Jul-09 15:15
MemberDiJ85-Jul-09 15:15 
QuestionMore than 1 Validation Rule per Control? Pin
Pink Floyd2-Nov-06 6:33
MemberPink Floyd2-Nov-06 6:33 
GeneralMany thanks Pin
oz_scooter4-May-06 21:39
Memberoz_scooter4-May-06 21:39 
Generalno regular expression validation if control is empty and not required Pin
Dutchpower22-Mar-06 1:28
MemberDutchpower22-Mar-06 1:28 
GeneralStrange problem on required currency textbox Pin
KjellSJ9-Mar-06 22:56
MemberKjellSJ9-Mar-06 22:56 
GeneralWeird behavor on initial value Pin
aldofer4-Mar-06 7:23
Memberaldofer4-Mar-06 7:23 
JokeAwesome Pin
OsirisFX2-Mar-06 11:28
MemberOsirisFX2-Mar-06 11:28 
GeneralValidationProvider Control Pin
yunus demiray31-Jan-06 11:36
Memberyunus demiray31-Jan-06 11:36 
GeneralRe: ValidationProvider Control Pin
User 19428916-Feb-06 7:50
MemberUser 19428916-Feb-06 7:50 
GeneralRe: ValidationProvider Control Pin
Kerem Kat27-Jul-07 11:23
MemberKerem Kat27-Jul-07 11:23 
JokeRe: ValidationProvider Control Pin
Jecho Jekov30-Nov-07 6:33
MemberJecho Jekov30-Nov-07 6:33 
GeneralAwesome control Pin
JGraves25-Jan-06 8:33
MemberJGraves25-Jan-06 8:33 
GeneralDateTimePicker Pin
Le_MuLoT21-Nov-05 11:42
MemberLe_MuLoT21-Nov-05 11:42 
GeneralJust love it Pin
KjellSJ19-Nov-05 3:09
MemberKjellSJ19-Nov-05 3:09 

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