为什么我的cmd1.ExecuteReader() 读不出数据啊

[dopushing]

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("userinfo.mdb"))
Dim ad As String
ad = "admin"
Dim cmd1 As New OleDbCommand("select * from bbs where username=" & ad, conn)
conn.Open()
Dim dr As OleDbDataReader = cmd1.ExecuteReader()
If dr.Read() Then
Label1.Text = dr.Item("username")
conn.Close()
End If
End Sub

[llsus]

你的Sql语句写错了，这样修改：

Dim   cmd1   As   New   OleDbCommand("select   *   from   bbs   where   username='"   &   ad +"'",   conn) 

[sjm2003]

Dim cmd1 As New OleDbCommand("select * from bbs where username=" & ad, conn)

这个是不是有问题啊

你直接把ad写到一起不好啊，干嘛写开，还多出两行没用的代码
Dim ad As String
ad = "admin"

建议：
你最好在数据查询前加个
try

....
end try
catch ex.ex....ion
messagebox.show （ex.message）

不然出错了也不知道是什么错误！像你这有可能是数据连接错误，也有可能是查询语句有错误！

还有就是 label1.text=dr.item("username")后面加个tostring（）；免得两头数据类型不相符.

[dwm250]

username的字段类型是什么？