我想在我的查询整合文本框.在网上搜索了几个小时后，我发现了下面的代码.有没有更好的解决办法?

Question

'code '

Dim conn as SqlConnection = new SqlConnection("SERVER=LOGICSERVERDB;DATABASE=sample;User=sa;Pwd=codename")
conn.Open()

Dim userId as String = txtUserId.Text
Dim sql as String = "SELECT name, password FROM users WHERE id=@userid"
Dim cmd as SqlCommand = new SqlCommand()
cmd.Connection = conn
cmd.CommandType = CommandType.Text
cmd.CommendText = sql
cmd.Parameters.AddWithValue("userid", userId);
Dim dr as SqlDataReader = cmd.ExecuteReader()

Answer 1

如果您乐意采用，只需做一个小的更改:

SqlConnection实现了idisable。尝试用Using块来包装它，原因如下:

不确定稍后是否在某处使用了您的姓名和密码。如果它在后面的部分不使用，为什么不直接发送作为参数和SELECT Count，然后是ExecuteScalar?

如果userId只使用一次，我将减少一行代码，而不声明变量

Using conn As New SqlConnection("SERVER=LOGICSERVERDB;DATABASE=sample;User=sa;Pwd=codename")
    conn.Open()
    Dim sql As String = "SELECT name, password FROM users WHERE id=@userid"
    Dim cmd As New SqlCommand
    cmd.Connection = conn
    cmd.CommandType = CommandType.Text
    cmd.CommandText = sql
    cmd.Parameters.AddWithValue("@userid", txtUserId.Text)
    Dim dr As SqlDataReader = cmd.ExecuteReader()            
End Using