ado连接access。请高手指教。

[c_word]

在FORM上建了1个Button控件和2个textbox控件。可是调试的结果是FROM字句语法错误。不知道为什么。
付上源代码：请高手指教。第一次写VB~
Dim a As String
Dim b As String

Private Sub Command1_Click()
Dim cn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim cnn As String
cnn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Downloads\2\Web1.mdb;Persist Security Info=False"
cn.Open cnn
Set rs = cn.Execute("SELECT sign FROM user WHERE UserName = a")
b = rs(sign)
End Sub

Private Sub Text1_KeyPress(KeyAscii As Integer)
a = KeyAscii
End Sub

Private Sub Text2_Change()
Text2.Text = b
End Sub

[sikeen]

("SELECT sign FROM user WHERE UserName = a")

撇開其他問題，至少也應該是這樣

("SELECT sign FROM user WHERE UserName = '" & a & "'")

[c_word]

还是提示这个错误~~~~~~~~

[fsroger]

SELECT sign FROM [user] WHERE UserName = 'a'

[fsroger]

SELECT sign FROM [user] WHERE UserName = '"& a &"'

[c_word]

现在提示为 Item cannot be found…………

[liuyiuhui]

sikeen(阿士)：说的有道理，如果你在user表中定义的字段Username是一个字
符型的，应该用sikeen那样的形式，如果你用的是字段是数字的话则是如下的
形式：("SELECT sign FROM user WHERE UserName = " & a )如果是日期
或其它形式，则更复杂一些，如果是图像的话，则要做相应的处理.
另外，你的变量a接收的是一个数字，即你敲的是A的话，实际上是A的ASCII，
好象是97(我没记住)，前不是字符 'A'
我觉得上面的过程，你的本义是：

'这2句可以删去
'Dim a As String
'Dim b As String

Private Sub Command1_Click()
Dim cn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim cnn As String
cnn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Downloads\2\Web1.mdb;Persist Security Info=False"
cn.Open cnn
Set rs = cn.Execute("SELECT sign FROM user WHERE UserName ='" & text1 & "'")
text2 = rs!sign
End Sub

[c_word]

恩。我去试试。

[c_word]

那text2的textbox控件怎么显示内容的？

[cnhgj]

"select sing from [user] where username='" & a & "'"

[sxs69]

数据量是否特别大（例如图象与声音文件）？在连接建立之后，TCP 协议将维护连接并确保数据的完整性。不过，这种连接需要更多的计算资源，因而是比较“昂贵”的。

[liuyiuhui]

text2 = rs!sign
这句话就是给text2的text属性赋值

[饮水需思源]

"select sign from [user] where username='" & a & "'"
text2.text=rs!sign &""

[饮水需思源]

'再改一下
"select sign from [user] where username='" & a & "'"
if rs.recrodcoutn>0 then
text2.text=rs!sign &""
else
text2.text=""
end if

[wamlaw]

Dim a As String
Dim b As String

Private Sub Command1_Click()
Dim cn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim cnn As String
cnn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Downloads\2\Web1.mdb;Persist Security Info=False"
cn.Open cnn
Set rs = cn.Execute("SELECT sign FROM user WHERE UserName = 'a'")
if rs.recordcount>0 then
b = rs.fields(0)
end if
End Sub

Private Sub Text1_change()
a = text1.text
End Sub

Private Sub Text2_Change()
Text2.Text = b
End Sub

[yinbin]

不能用USER这个字段命名，这是VB的专用的字

[dengyiwolf]

up

[zheng518]

我认为可能因为类型不符，造成该语句执行错误，尤其下面事件过程有问题，我只是试试。
Private Sub Text1_KeyPress(KeyAscii As Integer)
a = KeyAscii
End Sub

[huwei78]

改成这样
Set rs = cn.Execute("SELECT sign FROM user WHERE UserName = '" & a & "'")



a 是字符变量哦

[dgyujingjun]

Private Sub Command1_Click()
Dim cn As New ADODB.Connection
Dim rs As New ADODB.Recordset
dim SQL as string
Dim cnn As String
cnn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Downloads\2\Web1.mdb;Persist Security Info=False"
cn.Open cnn
SQL="SELECT sign FROM user WHERE UserName ='" + trim(text1) + "'"
rs.Open SQL, CNT, adOpenKeyset, adLockPessimistic
text2 = rs.fields("sign")
End Sub

[newste]

把user用[]挎起来要不还会有错误的[user]