private IServiceCallSite[] PopulateCallSites(
ServiceProvider provider,
ISet <Type> callSiteChain,
ParameterInfo[] parameters,
bool throwIfCallSiteNotFound)
{
var parameterCallSites = new IServiceCallSite[parameters.Length];
for (var index = 0; index < parameters.Length; index++)
{
var callSite = provider.GetServiceCallSite(parameters[index].ParameterType, callSiteChain);
if (callSite == null && parameters[index].HasDefaultValue)
{
callSite = new ConstantCallSite(parameters[index].DefaultValue);
}
if (callSite == null)
{
if (throwIfCallSiteNotFound)
{
throw new InvalidOperationException("不能解析服务。");
}
return(null);
}
parameterCallSites[index] = callSite;
}
return(parameterCallSites);
}
protected abstract TResult VisitConstant(ConstantCallSite constantCallSite, TArgument argument);
protected override object VisitConstant(ConstantCallSite constantCallSite, ServiceProvider provider)
{
return(constantCallSite.DefaultValue);
}
protected override Expression VisitConstant(ConstantCallSite constantCallSite, ParameterExpression provider)
{
return(Expression.Constant(constantCallSite.DefaultValue));
}
protected override Type VisitConstant(ConstantCallSite constantCallSite, CallSiteValidatorState state) => null;