WPF

Question

Hello,how to make validations for toolbox controls in xaml page?

Manoj Patel · Answer

Hi, I think there no one shot solution, u can make a public function and call every textbox below code is vb.net Public Sub chkblank(ByVal txtbx As TextBox) If String.IsNullOrEmpty(txtbx.Text) Then MsgBox("Please enter valid value") txtbx.Focus() End If End Sub or check this way Private Sub txtsgmName_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs) Handles txtsgmName.KeyDown If e.Key = 3 And String.IsNullOrEmpty(txtsgmName.Text) Then If String.IsNullOrEmpty(txtsgmName.Text) Then gmcls.msg("Please Enter Valid Name", "") e.Handled = True End If Else e.Handled = False End If End Sub

Manoj Patel · Answer

You have to bind it to a source and path, for example the following simple object: public class Class1 { public string Name { get; set; } } The object can be created by adding it to the window its resource collection. The source binds to the object and the path to its property [Name], which in this example is "0123456789". x:Key = "class1" Name = "0123456789" /> Lastly, you have to bind its source to this resource by Source={StaticResource class1} Height = "23" HorizontalAlignment = "Left" Margin = "118,60,0,0" Name = "CreateUserCPRTextbox" VerticalAlignment = "Top" Width = "120" > > Source = "{StaticResource class1}" Path = "Name" UpdateSourceTrigger = "PropertyChanged" ValidatesOnDataErrors = "true" > > ValidatesOnTargetUpdated = "True" MinimumLength = "10" MaximumLength = "10" ErrorMessage = "CPR nummer ikke gyldigt" /> ----------------------------------------- http://weblogs.asp.net/monikadyrda/archive/2009/06/24/wpf-textbox-validation.aspx WPF TextBox Validation Sample problem: set parameter by entering value into a TextBox, check if value is a number in given range, allow clicking a Button if validation was successful. ValidationRule ValidationRule is an abstract class from System.Windows.Controls that helps creating custom validation rules for user input. In this example a derived class DoubleRangeRule will check if user entered a number (double) within a given range (between Max and Min value). public class DoubleRangeRule : ValidationRule { public double Min { get; set; } public double Max { get; set; } public override ValidationResult Validate( object value , CultureInfo cultureInfo ) { double parameter = 0; try { if ( (( string ) value ).Length > 0 ) { parameter = Double.Parse( (String) value ); } } catch ( Exception e ) { return new ValidationResult( false , "Illegal characters or " + e.Message ); } if ( (parameter this .Min) || (parameter > this .Max) ) { return new ValidationResult( false , "Please enter value in the range: " + this .Min + " - " + this .Max + "." ); } return new ValidationResult( true , null ); } } Validation.ErrorTemplate Having defined ValidationRule as above if user input is invalid, TextBox will have a red border. Like everything in WPF it is possible to customize it by setting a custom ControlTemplate. My template shows a warning sign and a label explaining error made by user (why input is invalid): ControlTemplate x:Key ="TextBoxErrorTemplate" > StackPanel > StackPanel Orientation ="Horizontal" > Image Height ="16" Margin ="0,0,5,0" Source ="Assets/warning_48.png" /> AdornedElementPlaceholder x:Name ="Holder" /> StackPanel > Label Foreground ="Red" Content ="{Binding ElementName=Holder, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}" /> StackPanel > ControlTemplate > Read more about AdornedElement here . Binding to validation result On the result of validation can depend many things. For example I would like to bind button IsEnabled property to that deciding to enable button only in user input is valid. Simplest way, in my opinion is to check if TextBox has any validation errors and if no – make button enabled, disabled otherwise. With TextBox called Box (x:Name) binding of Button's IsEnabled property looks like that: IsEnabled="{Binding ElementName=Box, Path=(Validation.Errors)[0], Converter={StaticResource buttonEnabled}}" Final app Finally we get a TexBbox with validation rules, tips on incorrect input and a Button bound to correctness of input. TextBox x:Name ="Box" Validation . ErrorTemplate ="{StaticResource TextBoxErrorTemplate}" > TextBox.Text > Binding Path ="ValueInBox" UpdateSourceTrigger ="PropertyChanged" > Binding.ValidationRules > ValidationExpamples:DoubleRangeRule Min ="0.5" Max ="10" /> Binding.ValidationRules > Binding > TextBox.Text > TextBox > Button Content ="SaveChanges" IsEnabled ="{Binding ElementName=Box, Path=(Validation.Errors)[0], Converter={StaticResource buttonEnabled}}" /> If anyone had an idea how to do things like that a better way comments would be much appreciated. VS2008 project here . Monika Posted: Jun 24 2009, 06:05 PM by xmonix | with 8 comment(s)

mayuri · Answer

OK..Thanks for helping Manoj ...

mayuri · Answer

yahh this method is helpful but for limited purpose of validation...but my WPF window has a varying number of TextBoxes depending on several factors...e.g. registration page...so how can I write the validations which can be reusable for multiple texboxes?

mayuri · Answer

thnx but link u have provided is not working ...not showing the page..

Manoj Patel · Answer

HI Try this way http://stackoverflow.com/questions/6087468/wpf-validation-of-textbox-what-should-the-binding-look-like

WPF

Answers (6)