通过表名获取表结构

工作中为减少对数据库的写入次数，才用SqlBulkCopy对数据进行插入。需要获取表的结构。
获取表结构的代码如下：
 1  public static DataTable getTableSchema(string tableName)
 2         {
 3             DataTable dt = new DataTable();
 4 
 5             string sql = "SELECT syscolumns.name,systypes.name as datatype,syscolumns.isnullable,syscolumns.length FROM syscolumns, systypes WHERE syscolumns.xusertype = systypes.xusertype AND syscolumns.id = object_id('" + tableName + "')";
 6             SqlCommand cmd = new SqlCommand(sql,sqlConn);
 7             sqlConn.Open();
 8             SqlDataReader reader = cmd.ExecuteReader();
 9             while (reader.Read())
10             {
11                 try
12                 {
13                     dt.Columns.Add(new DataColumn(reader["name"].ToString(), SqlType2CsharpType(reader["datatype"].ToString())));
14                     Console.WriteLine(reader["isnullable"].ToString());
15                 }
16                 catch (Exception ex)
17                 {
18                     Console.WriteLine(ex.Message);
19                     Console.WriteLine(ex.StackTrace);
20                 }
21             }
22             sqlConn.Close();
23             return dt;
24         }
25         public static Type SqlType2CsharpType(string sqlType)
26         {
27             switch (sqlType)
28             {
29                 case "bigint":
30                     return typeof(Int64);
31                 case "binary":
32                     return typeof(Object);
33                 case "bit":
34                     return typeof(Boolean);
35                 case "char":
36                     return typeof(String);
37                 case "datetime":
38                     return typeof(DateTime);
39                 case "decimal":
40                     return typeof(Decimal);
41                 case "float":
42                     return typeof(Double);
43                 case "image":
44                     return typeof(Object);
45                 case "int":
46                     return typeof(int);
47                 case "money":
48                     return typeof(Decimal);
49                 case "nchar":
50                     return typeof(String);
51                 case "ntext":
52                     return typeof(String);
53                 case "nvarchar":
54                     return typeof(String);
55                 case "real":
56                     return typeof(Single);
57                 case "smalldatetime":
58                     return typeof(DateTime);
59                 case "smallint":
60                     return typeof(Int16);
61                 case "smallmoney":
62                     return typeof(Decimal);
63                 case "text":
64                     return typeof(String);
65                 case "timestamp":
66                     return typeof(Object);
67                 case "tinyint":
68                     return typeof(Byte);
69                 case "VarBinary":
70                     return typeof(Object);
71                 case "varchar":
72                     return typeof(String);
73                 case "Variant":
74                     return typeof(Object);
75                 case "xml":
76                     return typeof(Object);
77                 default:
78                     return null;
79             }
80         }
在使用SqlBulkCopy插入数据时，如果有自增长的列，在映射时去掉就好。