It seems that impossible to call SP which has output sql_variant parameters

[guffy1234]

As an example, it's impossible to call systems stored procedure to get range from a sequence:

        this.LoadStoredProc("sys.sp_sequence_get_range")
            .AddParam("sequence_name", sequence)
            .AddParam("range_size", range_size)
            .AddParam("range_first_value", out IOutParam<int> range_first_value)
            .AddParam("range_last_value", out IOutParam<int> range_last_value)
            .ExecNonQuery();

[verdie-g]

StoredProcedureEFCore/StoredProcedureEFCore/IStoredProcBuilder.cs

Line 65 in 6171d12

IStoredProcBuilder AddParam(DbParameter parameter);

This overload accepts a DbParameter so can you pass a SqlParameter with a SqlDbType.Variant.

[guffy1234]

yes, this code is workable:

var firstValueInRange = new SqlParameter("@range_first_value", SqlDbType.Variant)
            {
                Direction = ParameterDirection.Output
            };
            var lastValueInRange = new SqlParameter("@range_last_value", SqlDbType.Variant)
            {
                Direction = ParameterDirection.Output
            };
            await this.LoadStoredProc("sys.sp_sequence_get_range")
                .AddParam("@sequence_name", name)
                .AddParam("@range_size", range_size)
                .AddParam(firstValueInRange)
                .AddParam(lastValueInRange)
                .ExecNonQueryAsync();
            return new Tuple<int, int>((int)firstValueInRange.Value, (int)lastValueInRange.Value);

but probably it would be nice to find some way how to handle the case in a more elegant way.
convert to expected type when it possible. or allow to use IOutParam < object >

[verdie-g]

There is no plan to add database specific extension.