/// <summary> /// Validates the parameter value. /// </summary> /// <param name="context">The parameter context.</param> /// <returns>The validation result.</returns> public abstract ValidationResult Validate(CommandParameterContext context);
/// <summary> /// Gets a value for the parameter. /// </summary> /// <param name="context">The parameter context.</param> /// <param name="result">The resulting value.</param> /// <returns><c>true</c> if a value was provided; otherwise, <c>false</c>.</returns> public abstract bool TryGetValue(CommandParameterContext context, out object?result);
public static CommandValueLookup GetParameterValues(CommandTree?tree, ITypeResolver resolver)
{
var lookup = new CommandValueLookup();
var binder = new CommandValueBinder(lookup);
CommandValidator.ValidateRequiredParameters(tree);
while (tree != null)
{
// Process unmapped parameters.
foreach (var parameter in tree.Unmapped)
{
// Got a value provider?
if (parameter.ValueProvider != null)
{
var context = new CommandParameterContext(parameter, resolver, null);
if (parameter.ValueProvider.TryGetValue(context, out var result))
{
result = ConvertValue(resolver, lookup, binder, parameter, result);
lookup.SetValue(parameter, result);
CommandValidator.ValidateParameter(parameter, lookup, resolver);
continue;
}
}
if (parameter.IsFlagValue())
{
// Set the flag value to an empty, not set instance.
var instance = Activator.CreateInstance(parameter.ParameterType);
lookup.SetValue(parameter, instance);
}
else
{
// Is this an option with a default value?
if (parameter.DefaultValue != null)
{
var value = parameter.DefaultValue?.Value;
value = ConvertValue(resolver, lookup, binder, parameter, value);
binder.Bind(parameter, resolver, value);
CommandValidator.ValidateParameter(parameter, lookup, resolver);
}
else if (Nullable.GetUnderlyingType(parameter.ParameterType) != null ||
!parameter.ParameterType.IsValueType)
{
lookup.SetValue(parameter, null);
}
}
}
// Process mapped parameters.
foreach (var mapped in tree.Mapped)
{
if (mapped.Parameter.WantRawValue)
{
// Just try to assign the raw value.
binder.Bind(mapped.Parameter, resolver, mapped.Value);
}
else
{
if (mapped.Parameter.IsFlagValue() && mapped.Value == null)
{
if (mapped.Parameter is CommandOption option && option.DefaultValue != null)
{
// Set the default value.
binder.Bind(mapped.Parameter, resolver, option.DefaultValue?.Value);
}
else
{
// Set the flag but not the value.
binder.Bind(mapped.Parameter, resolver, null);
}
}