///<summary>
/// Uses the action pipeline to invoke the method.
///</summary>
///<param name="target"> The object instance to invoke the method on. </param>
///<param name="methodName"> The name of the method to invoke. </param>
///<param name="view"> The view. </param>
///<param name="source"> The source of the invocation. </param>
///<param name="eventArgs"> The event args. </param>
///<param name="parameters"> The method parameters. </param>
public static void Invoke(object target, string methodName, DependencyObject view = null, System.Windows.FrameworkContentElement source = null, object eventArgs = null, object[] parameters = null)
{
var context = new ActionExecutionContext {
Target = target,
#if WinRT
Method = target.GetType().GetRuntimeMethods().Single(m => m.Name == methodName),
#else
Method = target.GetType().GetMethod(methodName),
#endif
Message = new ActionMessage {
MethodName = methodName
},
View = view,
Source = source,
EventArgs = eventArgs
};
if (parameters != null)
{
parameters.Apply(x => context.Message.Parameters.Add(x as Parameter ?? new Parameter {
Value = x
}));
}
ActionMessage.InvokeAction(context);
}
void UpdateContext()
{
if (context != null)
{
context.Dispose();
}
context = new ActionExecutionContext {
Message = this,
Source = AssociatedObject
};
PrepareContext(context);
UpdateAvailabilityCore();
}
/// <summary>
/// Determines the parameters that a method should be invoked with.
/// </summary>
/// <param name="context">The action execution context.</param>
/// <param name="requiredParameters">The parameters required to complete the invocation.</param>
/// <returns>The actual parameter values.</returns>
public static object[] DetermineParameters(ActionExecutionContext context, ParameterInfo[] requiredParameters)
{
var providedValues = context.Message.Parameters.OfType <Parameter>().Select(x => x.Value).ToArray();
var finalValues = new object[requiredParameters.Length];
for (int i = 0; i < requiredParameters.Length; i++)
{
var parameterType = requiredParameters[i].ParameterType;
var parameterValue = providedValues[i];
var parameterAsString = parameterValue as string;
if (parameterAsString != null)
{
finalValues[i] = CoerceValue(parameterType,
EvaluateParameter(parameterAsString, parameterType, context), context);
}
else
{
finalValues[i] = CoerceValue(parameterType, parameterValue, context);
}
}
return(finalValues);
}
/// <summary>
/// Try to find a candidate for guard function, having:
/// - a name in the form "CanXXX"
/// - no generic parameters
/// - a bool return type
/// - no parameters or a set of parameters corresponding to the action method
/// </summary>
/// <param name="context">The execution context</param>
/// <returns>A MethodInfo, if found; null otherwise</returns>
static MethodInfo TryFindGuardMethod(ActionExecutionContext context)
{
#if WinRT
var guardName = "Can" + context.Method.Name;
var targetType = context.Target.GetType();
var guard = targetType.GetRuntimeMethods().SingleOrDefault(m => m.Name == guardName);
if (guard == null)
{
return(null);
}
if (guard.ContainsGenericParameters)
{
return(null);
}
if (!typeof(bool).Equals(guard.ReturnType))
{
return(null);
}
var guardPars = guard.GetParameters();
var actionPars = context.Method.GetParameters();
if (guardPars.Length == 0)
{
return(guard);
}
if (guardPars.Length != actionPars.Length)
{
return(null);
}
var comparisons = guardPars.Zip(
context.Method.GetParameters(),
(x, y) => x.ParameterType.Equals(y.ParameterType)
);
if (comparisons.Any(x => !x))
{
return(null);
}
return(guard);
#else
var guardName = "Can" + context.Method.Name;
var targetType = context.Target.GetType();
var guard = targetType.GetMethod(guardName);
if (guard == null)
{
return(null);
}
if (guard.ContainsGenericParameters)
{
return(null);
}
if (typeof(bool) != guard.ReturnType)
{
return(null);
}
var guardPars = guard.GetParameters();
var actionPars = context.Method.GetParameters();
if (guardPars.Length == 0)
{
return(guard);
}
if (guardPars.Length != actionPars.Length)
{
return(null);
}
var comparisons = guardPars.Zip(
context.Method.GetParameters(),
(x, y) => x.ParameterType == y.ParameterType
);
if (comparisons.Any(x => !x))
{
return(null);
}
return(guard);
#endif
}
