/// <summary>
/// Creates a collection of commands for the specified ViewModel.
/// </summary>
/// <param name="viewModel">
/// The ViewModel instance used to determine and create commands.
/// </param>
/// <returns>
/// An observable collection of commands for the View Model.
/// </returns>
/// <remarks>
/// This method leverages <see cref="CommandAttribute"/>, <see cref="CommandCanExecuteAttribute"/> and
/// <see cref="CommandCanExecuteChangedAttribute"/> to dynamically build the command collection.
/// </remarks>
static public CommandCollection CreateCommands(object viewModel)
{
// Validate
if (viewModel == null)
{
throw new ArgumentNullException("viewModel");
}
// Create lookup table
var lookup = new Dictionary <string, DynamicCommand>();
// Get type
var type = viewModel.GetType();
// Get type info
var typeInfo = type.GetTypeInfo();
// Get all methods
foreach (var method in typeInfo.DeclaredMethods)
{
// Check for Execute handlers
foreach (var executeAttr in method.GetCustomAttributes <CommandAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(executeAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, executeAttr.CommandName);
lookup[executeAttr.CommandName] = command;
}
// Make sure not already set
if (command.ExecuteMethod != null)
{
throw new InvalidOperationException(string.Format("CommandAttribute applied more than once for command '{0}' on type '{1}'", executeAttr.CommandName, type.Name));
}
// Set the Execute method
command.ExecuteMethod = method;
}
// Check for CanExecute handlers
foreach (var canExecuteAttr in method.GetCustomAttributes <CommandCanExecuteAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(canExecuteAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, canExecuteAttr.CommandName);
lookup[canExecuteAttr.CommandName] = command;
}
// Make sure not already set
if (command.CanExecuteMethod != null)
{
throw new InvalidOperationException(string.Format("CommandCanExecuteAttribute applied more than once for command '{0}' on type '{1}'", canExecuteAttr.CommandName, type.Name));
}
// Set the CanExecute method
command.CanExecuteMethod = method;
}
}
// Get all properties
foreach (var prop in typeInfo.DeclaredProperties)
{
// Check for Execute handlers
foreach (var executeChangedAttr in prop.GetCustomAttributes <CommandCanExecuteChangedAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(executeChangedAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, executeChangedAttr.CommandName);
lookup[executeChangedAttr.CommandName] = command;
}
// Add the property name
command.AddCanExecuteProperty(prop.Name);
}
}
// Done looking. Create and return collection.
return(new CommandCollection(lookup.Values));
}
/// <summary>
/// Creates a collection of commands for the specified ViewModel.
/// </summary>
/// <param name="viewModel">
/// The ViewModel instance used to determine and create commands.
/// </param>
/// <returns>
/// An observable collection of commands for the View Model.
/// </returns>
/// <remarks>
/// This method leverages <see cref="CommandAttribute"/>, <see cref="CommandCanExecuteAttribute"/> and
/// <see cref="CommandCanExecuteChangedAttribute"/> to dynamically build the command collection.
/// </remarks>
static public CommandCollection CreateCommands(object viewModel)
{
// Validate
if (viewModel == null) throw new ArgumentNullException("viewModel");
// Create lookup table
var lookup = new Dictionary<string, DynamicCommand>();
// Get type
var type = viewModel.GetType();
// Get type info
var typeInfo = type.GetTypeInfo();
// Get all methods
foreach (var method in typeInfo.DeclaredMethods)
{
// Check for Execute handlers
foreach (var executeAttr in method.GetCustomAttributes<CommandAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(executeAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, executeAttr.CommandName);
lookup[executeAttr.CommandName] = command;
}
// Make sure not already set
if (command.ExecuteMethod != null)
{
throw new InvalidOperationException(string.Format("CommandAttribute applied more than once for command '{0}' on type '{1}'", executeAttr.CommandName, type.Name));
}
// Set the Execute method
command.ExecuteMethod = method;
}
// Check for CanExecute handlers
foreach (var canExecuteAttr in method.GetCustomAttributes<CommandCanExecuteAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(canExecuteAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, canExecuteAttr.CommandName);
lookup[canExecuteAttr.CommandName] = command;
}
// Make sure not already set
if (command.CanExecuteMethod != null)
{
throw new InvalidOperationException(string.Format("CommandCanExecuteAttribute applied more than once for command '{0}' on type '{1}'", canExecuteAttr.CommandName, type.Name));
}
// Set the CanExecute method
command.CanExecuteMethod = method;
}
}
// Get all properties
foreach (var prop in typeInfo.DeclaredProperties)
{
// Check for Execute handlers
foreach (var executeChangedAttr in prop.GetCustomAttributes<CommandCanExecuteChangedAttribute>())
{
// Get or create dynamic command
DynamicCommand command = null;
if (!lookup.TryGetValue(executeChangedAttr.CommandName, out command))
{
command = new DynamicCommand(viewModel, executeChangedAttr.CommandName);
lookup[executeChangedAttr.CommandName] = command;
}
// Add the property name
command.AddCanExecuteProperty(prop.Name);
}
}
// Done looking. Create and return collection.
return new CommandCollection(lookup.Values);
}
