参数化连接的问题？

[eaqpi]

dim SqlStr="select * from [User] where 用户名= '@用户名'"
dim Conn as new sqlconnection
dim ds as new dataset
usering conn as new sqlconnection(MyData.conStr)
try
 conn.open()
 dim cmd as new sqlcommand(SQLstr,conn)
 cmd.parameters.addwithvalue("@用户名",UserName)
 cmd.commandtext =sqlstr
 dim da as new sqldataadapter(SqlStr,conn)
 da.fill(ds)
 'do....
cathch ex as exception
 debug.pring(ex.tostring)
 finally
 conn.close()
end try

在 运行的时候发现，参数没有被替换。
sqlstr连接字符串还是select * from [User] where 用户名= '@用户名'
是哪里错了？

[孟子E章]

dim SqlStr="select * from [User] where 用户名= @用户名"

注意没有单引号

[eaqpi]

没单引号也不成功！

[wuyq11]

dim SqlStr="select * from [User] where 用户名= @用户名"

[wuyq11]

Dim sql As String = "insert into Tb(title) values(@title)"
Dim com As New SqlCommand(sql, MyConn)
com.Parameters.AddWithValue("@title", title)
com.ExecuteNonQuery()
没问题

[eaqpi]

测试成功了，单步的时候那个值并不会被替换。CONSOLE.WRITE 出了的句子 是错的.....