SimpleButton.Command Property
Specifies the command that is executed when a user taps the button.
Namespace: DevExpress.XamarinForms.Editors
Assembly: DevExpress.XamarinForms.Editors.dll
NuGet Package: DevExpress.XamarinForms.Editors
Declaration
public ICommand Command { get; set; }
Property Value
Type | Description |
---|---|
ICommand | A command that exposes the ICommand interface. |
Remarks
Use Command property to set the action that occurs when a user taps the button. The CommandParameter property allows you to pass data to the Command.
You can also use the Clicked event to define the action on button tap.
Example
This example shows how to create a custom command with a parameter and execute it when a user taps the button.
In a view model, create a command that implements the ICommand interface:
using System.ComponentModel; using System.Windows.Input; namespace TestICommand.ViewModels { public class ValidationCommand : ICommand { public event EventHandler CanExecuteChanged; MainViewModel viewModel; public ValidationCommand(MainViewModel viewModel) { this.viewModel = viewModel; } public bool CanExecute(object Login) { if (string.IsNullOrEmpty((string)Login) || Login == null) { viewModel.ValidationResultText = "Login cannot be empty"; viewModel.TextHasError = true; return false; } viewModel.ValidationResultText = ""; viewModel.TextHasError = false; return true; } public void Execute(object Login) { viewModel.ValidationResultText = $"Login {Login} is correct"; } } public class MainViewModel : INotifyPropertyChanged { public MainViewModel() { buttonCommand = new ValidationCommand(this); } ICommand buttonCommand = null; public ICommand ButtonCommand { get { return buttonCommand; } set { if (buttonCommand != value) { buttonCommand = value; OnPropertyChanged("ButtonCommand"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void OnPropertyChanged(string name) { PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name)); } bool textHasError = false; public bool TextHasError { get { return textHasError; } set { if (textHasError != value) { textHasError = value; OnPropertyChanged("TextHasError"); } } } string validationResultText = ""; public string ValidationResultText { get { return validationResultText; } set { validationResultText = value; OnPropertyChanged("ValidationResultText"); } } } }
Bind the specified command to the
Command
property and define the CommandParameter value:<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-namespace:TestICommand" xmlns:vm="clr-namespace:TestICommand.ViewModels" x:Class="TestICommand.MainPage" xmlns:dxe="http://schemas.devexpress.com/xamarin/2014/forms/editors"> <ContentPage.BindingContext> <vm:MainViewModel/> </ContentPage.BindingContext> <StackLayout> <dxe:TextEdit x:Name="TextEditor" HasError="{Binding TextHasError}"/> <dxe:SimpleButton x:Name="MyButton" Text="Check" Command="{Binding ButtonCommand}" CommandParameter="{Binding Source={x:Reference TextEditor}, Path=Text}"/> <Label Text="{Binding ValidationResultText}" HorizontalOptions="Center"/> </StackLayout> </ContentPage>