小弟初学VB，现要设计一登录窗口，但无法调用数据库数据与输入数据进行比较判断，现程序如下：
Private Sub CmdOk_Click()

'根据操作工号查找用户记录

Logging.logindata.Recordset.Findfirst("userid='" + txtusername"'")
if not logging.logindata.recordset.nomatch then

'用户输入了正确的密码

If TxtPassword.Text = Logging.logindata.Recordset.Fields("password") Then

'隐藏当前登陆窗体

Me.Visible = False

'显示程序主窗体

Main.Show

'用户输入的密码不正确

End If

'没有找到该用户记录

Else

MsgBox "请输入正确的用户名!", vbOKOnly, "用户名不存在!"

End If

End Sub

其中findfirst与nomatch提示方法错误，请各位大侠指点是否有其它办法调用数据库信息进行处理，菜鸟拜谢！！

'以下的是我刚写的，没有调试过。用的是Access数据库。
Option Explicit
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim rs1 As ADODB.Recordset

Private Sub CmdOK_Click()
Dim ConStr As String
If TxtUserName.Text = "" Then
MsgBox "請輸入用戶名!", vbOKOnly + vbExclamation, "登錄"
TxtUserName.SetFocus
Exit Sub
End If
Set cn = New ADODB.Connection
Set rs = New ADODB.Recordset
ConStr = "Provider=Microsoft.Jet.OLEDB.4.0;" _
& "Data Source=" & App.Path & "\StuAcc.Mdb"
cn.Open ConStr
cn.CursorLocation = adUseServer
rs.Open "Select * From User_Property", cn, adOpenKeyset, adLockPessimistic
If rs.RecordCount > 0 Then
If TxtUserName.Text <> "" Then
Set rs1 = New ADODB.Recordset
rs1.Open "Select * From User_Property Where User_Name= '" & TxtUserName.Text & "'", cn, adOpenKeyset, adLockPessimistic
If rs.RecordCount > 0 Then
If TxtPassWord.Text <> "" Then
If rs.Fields("User_Name") = TxtUserName.Text And rs.Fields("User_password") = TxtPassWord.Text And rs.Fields("User_Popedom") = Cbop.Text Then
FrmMain.Show
rs1.Close
Unload Me
Else
If rs1.Fields("User_password") <> TxtPassWord.Text Then
MsgBox "密碼錯誤,請與管理員聯系!", vbCritical + vbOKOnly, "密碼錯誤"
TxtPassWord.SetFocus
TxtPassWord.SelStart = 0
TxtPassWord.SelLength = Len(TxtPassWord.Text)
Exit Sub
Else
If rs1.Fields("User_Popedom") <> Cbop.Text Then
MsgBox "權限錯誤,請與管理員聯系!", vbOKOnly + vbCritical, "權限錯誤"
Cbop.SetFocus
Exit Sub
End If
End If
End If
Else
MsgBox "請輸入密碼!", vbOKOnly, "登錄"
TxtPassWord.SetFocus
Exit Sub
End If
Else
MsgBox "沒有該用戶,請與管理員聯系!", vbOKCancel + vbExclamation, "登錄"
Exit Sub
End If
End If
Else
MsgBox "沒有用戶信息,請確定!", vbExclamation + vbOKCancel, "登錄"
TxtUserName.SetFocus
Exit Sub
End If
rs.Close
End Sub

Private Sub CmdCancle_Click()
Unload Me
End Sub

Private Sub Form_Load()
Move Screen.Width / 2 - Width / 2, Screen.Height / 2 - Height / 2
Cbop.AddItem "管理員"
Cbop.AddItem "普通操作員"
Dim MyConStr As String
Dim UserCount As Integer
Dim Mycn As New ADODB.Connection
Dim Myrs As New ADODB.Recordset
MyConStr = "Provider=Microsoft.Jet.OLEDB.4.0;" _
& "Data Source=" & App.Path & "\StuAcc.mdb"
Mycn.Open MyConStr
Mycn.CursorLocation = adUseClient
Myrs.Open "Select * From User_Property", Mycn, adOpenKeyset, adLockPessimistic
If Myrs.RecordCount <= 0 Then
UserCount = MsgBox("沒有用戶,請先注冊!", vbYesNo + vbExclamation, "登錄")
If UserCount = vbYes Then FrmAddUser.Show
Myrs.Close
Mycn.Close
Set Myrs = Nothing
Set Mycn = Nothing
Unload Me
End If
End Sub

Private Sub Form_Unload(Cancel As Integer)
Set cn = Nothing
End Sub

以下代码是不才以前写的一个登陆窗口，用的也是ACCESS数据库，只供参考
1、首先建立一个ACCESS数据库为ZYDN.MDB,再建立一个名为“用户名与密码”的数据表，添加两个字段：用户名，密码。
2、在窗体上建立一个ADODC控件、三个LABEL控件、两个TEXTBOX与两个COMMANDBUTTON控件，代码如下：
Private Sub Command1_Click()
While Not Adodc1.Recordset.EOF
For i = 0 To Adodc1.Recordset.RecordCount - 1
If Text1.Text = Adodc1.Recordset.Fields("用户名").Value And Text2.Text = Adodc1.Recordset.Fields("密码").Value Then
Form6.mnuuse.Enabled = flase 'form6为主窗口，mnuuse为添加用户名与密码的菜单
If Text1.Text = "ilove" And Text2.Text = "2005" Then 'ilove与2005分别为超级用户名与密码，可添加用户名与密码
Form6.mnuuse.Enabled = True
Load Form6
Form6.Show
Form7.Hide 'form7为登陆窗口
Exit Sub
End If
Load Form6
Form6.Show
Form7.Hide
Exit Sub
End If
Adodc1.Recordset.MoveNext
Next i
Wend
MsgBox "用户名或密码有误", , "提示"
Adodc1.Recordset.MoveFirst
Text1.Text = ""
Text2.Text = ""
Text1.SetFocus
End Sub

Private Sub Command2_Click()
End
End Sub

Private Sub Form_Load()
Dim str As String
str = App.Path
If Right(str, 1) <> "\" Then
str = str & "\"
End If
str = "Provider=Microsoft.Jet.OLEDB.3.51;Persist Security Info=False;Data Source=" & str & "\zydn.mdb"
Adodc1.ConnectionString = str
Adodc1.CommandType = adCmdText
Adodc1.RecordSource = "select * from 用户与密码"
Adodc1.Refresh
End Sub