Me.errorProvider1.SetError(textBox1, errorMsg) ' Set the ErrorProvider error with the text to display. ' Cancel the event and select the text to be corrected by the user. If Not ValidEmailAddress(textBox1.Text, errorMsg) Then Private Sub textBox1_Validating(ByVal sender As Object, _īyVal e As ) Handles textBox1.Validating ' Confirm that there is an and a "." in the email address, and in the correct order.ĮrrorMessage = "Email address must be valid email address format." + ControlChars.Cr + _ Private Function ValidEmailAddress(ByVal emailAddress As String, ByRef errorMessage As String) As BooleanĮrrorMessage = "Email address is required." Confirm that there is an and a "." in the email address, and in the correct > -1)ĮrrorMessage = "email address must be valid email address format.\n" + Confirm that the email address string is not empty.ĮrrorMessage = "email address is required." Public bool ValidEmailAddress(string emailAddress, out string errorMessage) Private void textBox1_Validated(object sender, System.EventArgs e) If(!ValidEmailAddress(textBox1.Text, out errorMsg)) Private void textBox1_Validating(object sender, *errorMessage = "email address must be valid email address format.\n" + If ( emailAddress->IndexOf( ".", emailAddress->IndexOf( ) ) > emailAddress->IndexOf( ) ) Confirm that there is an and a "." in the email address, and in the correct order. *errorMessage = "email address is required." Confirm that the email address String* is not empty. If all conditions have been met, clear the ErrorProvider of errors.ĮrrorProvider1->SetError( textBox1, "" ) īool ValidEmailAddress( String^ emailAddress, interior_ptr errorMessage ) Void textBox1_Validated( Object^ sender, System::EventArgs^ e ) This->errorProvider1->SetError( textBox1, errorMsg ) Set the ErrorProvider error with the text to display. TextBox1->Select( 0, textBox1->Text->Length ) Cancel the event and select the text to be corrected by the user. If ( !ValidEmailAddress( textBox1->Text, &errorMsg ) ) Void textBox1_Validating( Object^ sender, System::ComponentModel::CancelEventArgs^ e ) In diesem Beispiel ist erforderlich, dass ein TextBox Steuerelement ErrorProvider in einem Formular erstellt wurde. Wenn sich die E-Mail-Adresse nicht im Standardformat (enthält and ".") befindet, schlägt die Überprüfung fehl, wird ein ErrorProvider Symbol angezeigt, und das Ereignis wird abgebrochen. Im folgenden Codebeispiel wird die abgeleitete Klasse TextBox verwendet und eine E-Mail-Adresse überprüft, die der Benutzer eingibt. public:Įvent System::ComponentModel::CancelEventHandler ^ Validating public event Validating member this.Validating : Public Custom Event Validating As CancelEventHandler Ereignistyp CancelEventHandler Beispiele Return string.Join("\n", results.Select(x => x.Tritt ein, wenn das Steuerelement eine Validierung ausführt. New ValidationContext(this, null, null), results, true) Var result = Validator.TryValidateObject(this, Var result = Validator.TryValidateProperty( Var propertyDescriptor = TypeDescriptor.GetProperties(this) There is a Validator class in which has a couple of methods which allows us to validate an object or a property of an object using validation attributes: using To bring validation attributes support to our model classes, we need to implement IDataErrorInfo. Implementing IDataErrorInfo using Data Annotations Validation Attributes Item: Gets the error message for the property with the given name.Error: Gets an error message indicating what is wrong with this object.Here is the interface definition: public interface IDataErrorInfo For example DataRowView which is the main model which is usually used in classic ADO.NET applications, has implemented IDataErrorInfo. To be able to show model errors in DataGridView or showing errors using ErrorProvider the model which you are using in data binding should implement IDataErrorInfo. The framework also supports showing error in DataGridView. To show validation errors in Windows Forms, the frame work has an ErrorProvider component. Data Annotation Validation attributes enable you to perform model validation simply by decorating class properties with validation attributes such as the Required, StringLength, RegularExpression, Range, Url, etc. In this post, I’ll show how to use Data Annotation Validation attributes to perform validation in a Windows Forms Application.
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