FewA few days ago, I was looking for simple pagination example and I decided to write my own version. It is one of my first apps using MVVM Pattern, so I am not sure I did right. I would appreciate if you could tell if I did something wrong, or used bad programming practises or whatever.
github.com/Dessembrae/MVVM-ListView-PaginationGitHub
Ok so here we have a MainWindow:MainWindow:
<Window x:Class="MVVMListViewPagination.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:userControls="clr-namespace:MVVMListViewPagination.Views"
Title="MVVM - ListView Pagination" Height="350" Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="45" />
</Grid.RowDefinitions>
<ListView ItemsSource="{Binding ViewList.View}" Margin="5">
<ListView.View>
<GridView>
<GridViewColumn Header="Id" Width="40" DisplayMemberBinding="{Binding Id}" />
<GridViewColumn Header="Name" Width="150" DisplayMemberBinding="{Binding Name}" />
<GridViewColumn Header="Surname" Width="150" DisplayMemberBinding="{Binding Surname}" />
</GridView>
</ListView.View>
</ListView>
<userControls:PaginationElements Grid.Row="1" Margin="5" />
</Grid>
And User Control with buttons for pagination:
<UserControl x:Class="MVVMListViewPagination.Views.PaginationElements"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d" >
<UserControl.Resources>
<Style TargetType="Button">
<Setter Property="Margin" Value="5" />
</Style>
<Style TargetType="TextBlock">
<Setter Property="Margin" Value="5" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
</UserControl.Resources>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
<Button Content="First" Command="{Binding FirstCommand}"/>
<Button Content="Previous" Command="{Binding PreviousCommand}"/>
<TextBlock Width="auto" Text="{Binding CurrentPage}"/>
<TextBlock Text="of"/>
<TextBlock Width="auto" Text="{Binding TotalPage}"/>
<Button Content="Next" Command="{Binding NextCommand}"/>
<Button Content="Last" Command="{Binding LastCommand}"/>
</StackPanel>
<Window x:Class="MVVMListViewPagination.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:userControls="clr-namespace:MVVMListViewPagination.Views"
Title="MVVM - ListView Pagination" Height="350" Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="45" />
</Grid.RowDefinitions>
<ListView ItemsSource="{Binding ViewList.View}" Margin="5">
<ListView.View>
<GridView>
<GridViewColumn Header="Id" Width="40" DisplayMemberBinding="{Binding Id}" />
<GridViewColumn Header="Name" Width="150" DisplayMemberBinding="{Binding Name}" />
<GridViewColumn Header="Surname" Width="150" DisplayMemberBinding="{Binding Surname}" />
</GridView>
</ListView.View>
</ListView>
<userControls:PaginationElements Grid.Row="1" Margin="5" />
</Grid>
And my ViewModel:User Control with buttons for pagination:
namespace MVVMListViewPagination.ViewModels
{
class MainViewModel : BaseViewModel
{
#region Commands
public ICommand PreviousCommand { get; private set; }
public ICommand NextCommand { get; private set; }
public ICommand FirstCommand { get; private set; }
public ICommand LastCommand { get; private set; }
#endregion
#region Fields And Properties
int itemPerPage = 15;
int itemcount;
private int _currentPageIndex;
public int CurrentPageIndex
{
get { return _currentPageIndex; }
set { _currentPageIndex = value; OnPropertyChanged("CurrentPage"); }
}
public int CurrentPage
{
get { return _currentPageIndex + 1; }
}
private int _totalPage;
public int TotalPage
{
get { return _totalPage; }
set { _totalPage = value; OnPropertyChanged("TotalPage"); }
}
public CollectionViewSource ViewList { get; set; }
public ObservableCollection<Person> peopleList = new ObservableCollection<Person>();
#endregion
#region Pagination Methods
public void ShowNextPage()
{
CurrentPageIndex++;
ViewList.View.Refresh();
}
public void ShowPreviousPage()
{
CurrentPageIndex--;
ViewList.View.Refresh();
}
public void ShowFirstPage()
{
CurrentPageIndex = 0;
ViewList.View.Refresh();
}
public void ShowLastPage()
{
CurrentPageIndex = TotalPage - 1;
ViewList.View.Refresh();
}
void view_Filter(object sender, FilterEventArgs e)
{
int index = ((Person)e.Item).Id - 1;
if (index >= itemPerPage * CurrentPageIndex && index < itemPerPage * (CurrentPageIndex + 1))
{
e.Accepted = true;
}
else
{
e.Accepted = false;
}
}
private void CalculateTotalPages()
{
TotalPage = (itemcount / itemPerPage);
if (itemcount % itemPerPage != 0)
{
TotalPage += 1;
}
}
#endregion
public MainViewModel()
{
populateList();
ViewList = new CollectionViewSource();
ViewList.Source = peopleList;
ViewList.Filter += new FilterEventHandler(view_Filter);
CurrentPageIndex = 0;
itemcount = peopleList.Count;
CalculateTotalPages();
NextCommand = new NextPageCommand(this);
PreviousCommand = new PreviousPageCommand(this);
FirstCommand = new FirstPageCommand(this);
LastCommand = new LastPageCommand(this);
}
private void populateList()
{
for (int i = 0; i < 100; i++)
{
peopleList.Add(new Person(i, "Jack", "Black"));
}
}
}
}
<UserControl x:Class="MVVMListViewPagination.Views.PaginationElements"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d" >
<UserControl.Resources>
<Style TargetType="Button">
<Setter Property="Margin" Value="5" />
</Style>
<Style TargetType="TextBlock">
<Setter Property="Margin" Value="5" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
</UserControl.Resources>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
<Button Content="First" Command="{Binding FirstCommand}"/>
<Button Content="Previous" Command="{Binding PreviousCommand}"/>
<TextBlock Width="auto" Text="{Binding CurrentPage}"/>
<TextBlock Text="of"/>
<TextBlock Width="auto" Text="{Binding TotalPage}"/>
<Button Content="Next" Command="{Binding NextCommand}"/>
<Button Content="Last" Command="{Binding LastCommand}"/>
</StackPanel>
ViewModel:
namespace MVVMListViewPagination.ViewModels
{
class MainViewModel : BaseViewModel
{
#region Commands
public ICommand PreviousCommand { get; private set; }
public ICommand NextCommand { get; private set; }
public ICommand FirstCommand { get; private set; }
public ICommand LastCommand { get; private set; }
#endregion
#region Fields And Properties
int itemPerPage = 15;
int itemcount;
private int _currentPageIndex;
public int CurrentPageIndex
{
get { return _currentPageIndex; }
set { _currentPageIndex = value; OnPropertyChanged("CurrentPage"); }
}
public int CurrentPage
{
get { return _currentPageIndex + 1; }
}
private int _totalPage;
public int TotalPage
{
get { return _totalPage; }
set { _totalPage = value; OnPropertyChanged("TotalPage"); }
}
public CollectionViewSource ViewList { get; set; }
public ObservableCollection<Person> peopleList = new ObservableCollection<Person>();
#endregion
#region Pagination Methods
public void ShowNextPage()
{
CurrentPageIndex++;
ViewList.View.Refresh();
}
public void ShowPreviousPage()
{
CurrentPageIndex--;
ViewList.View.Refresh();
}
public void ShowFirstPage()
{
CurrentPageIndex = 0;
ViewList.View.Refresh();
}
public void ShowLastPage()
{
CurrentPageIndex = TotalPage - 1;
ViewList.View.Refresh();
}
void view_Filter(object sender, FilterEventArgs e)
{
int index = ((Person)e.Item).Id - 1;
if (index >= itemPerPage * CurrentPageIndex && index < itemPerPage * (CurrentPageIndex + 1))
{
e.Accepted = true;
}
else
{
e.Accepted = false;
}
}
private void CalculateTotalPages()
{
TotalPage = (itemcount / itemPerPage);
if (itemcount % itemPerPage != 0)
{
TotalPage += 1;
}
}
#endregion
public MainViewModel()
{
populateList();
ViewList = new CollectionViewSource();
ViewList.Source = peopleList;
ViewList.Filter += new FilterEventHandler(view_Filter);
CurrentPageIndex = 0;
itemcount = peopleList.Count;
CalculateTotalPages();
NextCommand = new NextPageCommand(this);
PreviousCommand = new PreviousPageCommand(this);
FirstCommand = new FirstPageCommand(this);
LastCommand = new LastPageCommand(this);
}
private void populateList()
{
for (int i = 0; i < 100; i++)
{
peopleList.Add(new Person(i, "Jack", "Black"));
}
}
}
}
And last snippet is the code for one of the Command classess:One of the Command classes:
namespace MVVMListViewPagination.Commands
{
class FirstPageCommand : ICommand
{
private MainViewModel viewModel;
public FirstPageCommand(MainViewModel viewModel)
{
this.viewModel = viewModel;
}
public bool CanExecute(object parameter)
{
if (viewModel.CurrentPageIndex == 0)
return false;
else
return true;
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public void Execute(object parameter)
{
viewModel.ShowFirstPage();
}
}
}
namespace MVVMListViewPagination.Commands
{
class FirstPageCommand : ICommand
{
private MainViewModel viewModel;
public FirstPageCommand(MainViewModel viewModel)
{
this.viewModel = viewModel;
}
public bool CanExecute(object parameter)
{
if (viewModel.CurrentPageIndex == 0)
return false;
else
return true;
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public void Execute(object parameter)
{
viewModel.ShowFirstPage();
}
}
}
I'm not a professional programmer, so all my knowledge comes from tutorials. I was trying to mantain a MVVM Pattern and I would like to know if I succeded. And alsosucceeded, as well as any constructive criticism about my skills as a programmer in overall will be appreciated.
