的这就是连接首先，我所看到的字符串连接导致要查询的一部分的

Thats the first place where I have seen string concatenation causing conn to be part of query.

您错位字符串引号，你的说法应该是：

You misplaced string quotes, your statement should be:

SqlCommand cmd = 
  new SqlCommand("Insert into NOTESMAKER(NOTESMAKER) Values('" + NotesMaker + "'",con);

在你目前的code，你通过字符串INSERT INTO NOTESMAKER（NOTESMAKER）VALUES（'+ NotesMaker +'，CON），因此，连接属性没有初始化，因此例外。

In your current code, you are passing string "Insert into NOTESMAKER(NOTESMAKER) Values('"+NotesMaker+"',con)", hence the connection property is not initialized and hence the exception.

您不应该使用字符串连接创建查询，而是使用参数。这将节省您从 SQL注入。这样的：

You should never use string concatenation for creating queries, instead use Parameters. This will save you from SQL Injection. Like:

using(SqlConnection con = new SqlConnection("connectionstring"))
using(SqlCommand cmd = new SqlCommand("Insert into NOTESMAKER(NOTESMAKER) Values(@NotesMaker)",con))
{
    cmd.Parameters.AddWithValue("@NotesMaker", NotesMaker);
    con.Open();
    cmd.ExecuteNonQuery();
}