public static bool TryGet <T>(this IMFAttributes input, Guid key, IFormatProvider provider, out T value)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (input.GetItemType(key, out var type).IsError)
{
value = default;
return(false);
}
T item;
switch (type)
{
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_BLOB:
if (typeof(T) == typeof(byte[]))
{
value = (T)(object)GetBlob(input, key);
return(true);
}
var bytes = GetBlob(input, key);
if (!Conversions.TryChangeType(bytes, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_DOUBLE:
var dbl = GetDouble(input, key);
if (!Conversions.TryChangeType(dbl, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_GUID:
var guid = GetGuid(input, key);
if (!Conversions.TryChangeType(guid, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_STRING:
var s = GetString(input, key);
if (!Conversions.TryChangeType(s, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_UINT32:
var ui = GetUInt32(input, key);
if (!Conversions.TryChangeType(ui, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_UINT64:
var ul = GetUInt64(input, key);
if (!Conversions.TryChangeType(ul, provider, out item))
{
value = default;
return(false);
}
value = item;
return(true);
case _MF_ATTRIBUTE_TYPE.MF_ATTRIBUTE_IUNKNOWN:
var comType = ComObject.GetGenericComObjectComType(typeof(T));
if (comType == null)
{
value = (T)GetUnknown(input, key, typeof(T).GUID);
return(value != null);
}
var unk = GetUnknown(input, key, comType.GUID);
if (unk == null)
{
value = default;
return(false);
}
value = (T)(object)ComObject.WrapAsGeneric(comType, unk);
return(true);
default:
throw new NotSupportedException();
}
}