Invalid cast from 'System.String' to 'System.Guid'

My Id is defined in tSQL as

id NVARCHAR (128) DEFAULT (NEWID()) NOT NULL

and in C# as

public Guid Id { get; set; }

Dapper generates an error Invalid cast from 'System.String' to 'System.Guid'. One solution (from here) is to add a private IdString thus

private string IdString { get; set; }
public Guid Id
{
    get
    {
        return new Guid(IdString);
    }
    set
    {
        IdString = value.ToString();
    }
}

and changing the tSQL from id to Id AS IdString.

It's a bit painful not to be able to use SELECT * because of that alias.

Using Guid as an id column seems common practice.

Should there not be a built in mechanism for casting between Guids and strings?

Start by reproducing the reported mapping with an NVARCHAR(128) SQL id containing a GUID and a C# Guid property, then inspect Dapper's type-conversion and member-mapping path. Done should mean the existing SELECT * shape maps the string-backed id to Guid without requiring an alias or private backing property.