WPF

Question

Hellohow 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 = 1186000 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 =0050 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