Converting from DbType to [Sql]DbType is easy

I often see question on how to convert from DbType to SqlDbType (or any other *DbType). This is often required if you do some database independent code with ado.net. One way is certainly a gigantic switch block, such as:

private SqlDbType FromDbType(DbType type)
{
    switch (type)
    {
        case System.Data.DbType.AnsiStringFixedLength:
        case System.Data.DbType.StringFixedLength:
            return SqlDbType.Char; ;
        case System.Data.DbType.AnsiString:
        case System.Data.DbType.String:
            return SqlDbType.VarChar;
        case System.Data.DbType.Binary:
            return SqlDbType.Binary;
                  ........
}

However, this is not the best solution as elegant conversion method is already present within .net. Here it is:

DbType type = DbType.Int32;
SqlParameter parm = new SqlParameter();
try
{
  parm.DbType = type;
}
catch (Exception ex)
{
  // can't map
}
SqlDbType sqlDbType = parm.SqlDbType;

The trick is to use database specific parameter, in this case Sql Server's SqlParameter. And don't forget to wrap DbType assignment in try/catch block as an ArgumentException will be thrown when mapping doesn't exist between given DbType and target database specific type.

The implementation could be nicer (perhaps through a static method) but hey, it works just fine.