[SQL][C#]SqlCommand.Parameters¤ËnullÃͤòÆþ¤ì¤ëÊýË¡

using System.Data.SqlClient;
using System.Data.SqlTypes;
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cmd.Parameters["@sHoge"].Value = SqlString.Null;
cmd.Parameters["@dHoge"].Value = SqlDateTime.Null;
cmd.Parameters["@nHoge"].Value = SqlInt32.Null;
cmd.Parameters["@bHoge"].Value = SqlBoolean.Null;

DataRow row;
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row["hoge"] = System.DBNull.Value;