TextEditBase.ReturnCommandParameter Property

Specifies the parameter passed to the ReturnCommand.

Namespace: DevExpress.XamarinForms.Editors

Assembly: DevExpress.XamarinForms.Editors.dll

Declaration

public object ReturnCommandParameter { get; set; }

Property Value

Type Description
Object

A parameter object.

Remarks

Use the ReturnCommandParameter property with ReturnCommand to pass data to the command.

Examples

This example shows how to create a custom command with a parameter and execute it when a user taps the button.

Command Validation Example

  1. 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");
                }
            }
        }
    }
    
  2. 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="clr-namespace:DevExpress.XamarinForms.Editors;
                      assembly=DevExpress.XamarinForms.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>
    
See Also