c# - SqlCommand 参数化 SQL 错误：必须声明标量变量“@ObjectType”

Question

我收到此错误：

必须声明标量变量“@ObjectType”。

知道为什么吗？如果我硬编码值，则查询有效。

public static DataSet GetDatabaseObjectHistory(string objectType, 
                                               string schemaName, 
                                               string objectName, 
                                               string msConnectionString)
{
   using (SqlConnection sqlConnection = new SqlConnection()
                        {
                           ConnectionString = msConnectionString
                        })
   {
      sqlConnection.Open();

      using (DataSet ds = new DataSet())
      {
          #region sqlGetSchemaObjects
          const string sql = @"SELECT
                                           RowId
                                          ,EventTime
                                          ,LoginName
                                          ,UserName
                                          ,DatabaseName
                                          ,SchemaName
                                          ,ObjectName
                                          ,ObjectType
                                          ,DDLCommand
                                        FROM
                                           Audit_Log
                                        WHERE
                                            Audit_Log.ObjectType = @ObjectType AND
                                            Audit_Log.SchemaName = @SchemaName AND
                                            Audit_Log.ObjectName = @ObjectName";
          #endregion

          SqlCommand sqlCommand = new SqlCommand(sql, sqlConnection);
          sqlCommand.CommandType = CommandType.Text;

          sqlCommand.Parameters.AddWithValue("@ObjectType", objectType);
          sqlCommand.Parameters.AddWithValue("@SchemaName", schemaName);
          sqlCommand.Parameters.AddWithValue("@ObjectName", objectName);

          using (SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sql, sqlConnection))
          {
              sqlDataAdapter.Fill(ds, sql);
          }

          ds.Tables[0].TableName = "Object History";
          return ds;
      }
   }
   return null;
}

Answer 1

尝试以下操作：

public static DataSet GetDatabaseObjectHistory(
    string objectType,
    string schemaName,
    string objectName,
    string msConnectionString
)
{
    const string sql = 
        @"SELECT
              RowId,
              EventTime,
              LoginName,
              UserName,
              DatabaseName,
              SchemaName,
              ObjectName,
              ObjectType,
              DDLCommand
          FROM
              Audit_Log
          WHERE
              Audit_Log.ObjectType = @ObjectType AND
              Audit_Log.SchemaName = @SchemaName AND
              Audit_Log.ObjectName = @ObjectName
        ";

    using (SqlConnection con = new SqlConnection(msConnectionString))
    using (SqlCommand cmd = con.CreateCommand())
    {
        con.Open();
        cmd.CommandText = sql;

        cmd.Parameters.AddWithValue("@ObjectType", objectType);
        cmd.Parameters.AddWithValue("@SchemaName", schemaName);
        cmd.Parameters.AddWithValue("@ObjectName", objectName);

        using (SqlDataAdapter da = new SqlDataAdapter(cmd))
        {
            DataSet ds = new DataSet();
            da.Fill(ds);
            ds.Tables[0].TableName = "Object History";
            return ds;
        }
    }
}