应用程序的登陆框，老是提示用户不存在，大虾帮忙看看

[海大富运动]

Private Sub BtOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtOK.Click
Try
Me.Text = "正在验证...."
Me.Cursor = System.Windows.Forms.Cursors.WaitCursor
Dim comstr As String
Dim mydataset As New DataSet
comstr = "select 密码 from 一般用户 where 用户名='" & Trim(TxtUserName.Text) & "'"
mydataset.Clear()
Dim adapter As New SqlDataAdapter(comstr, SqlConnection1)
adapter.Fill(mydataset, "table1") '判断密码是否正确
If mydataset.Tables("table1").Rows(0).Item(0) = Trim(TxtPassword.Text) Then
'如果查找不到任何行，则此处出现异常
UserInf(0) = Trim(TxtUserName.Text)
UserInf(1) = CmbPurview.Text
If CmbPurview.Text <> "管理员" Then
With ob_MainForm
.BtGoods.Visible = False
.BtFinance.Visible = False
.BtEmployee.Visible = False
.BtSaleHistory.Visible = False
End With
End If
ob_MainForm.Show()
Me.Hide()
Else
MsgBox("密码错误!")
TxtPassword.Text = ""
Me.Text = ""
Me.Cursor = System.Windows.Forms.Cursors.Arrow
TxtPassword.Focus()

End If
Catch ex As Exception
MsgBox("用户不存在!", MsgBoxStyle.OKOnly, "提示")
TxtUserName.Text = ""
TxtPassword.Text = ""
Me.Text = ""
Me.Cursor = System.Windows.Forms.Cursors.Arrow

End Try
End Sub

数据库的结构是 用户名 密码 权限
admin 123456

[caicheng]

跟踪调试一下，确认数据有没有成功的从数据库读出

[caicheng]

还有在这种场合建议使用datareader 而不是dataAdapter以简省系统开销

[chinahth]

你把查询出来的数据绑定到DATAGRID中看看

[WTaoboy]

strSql="select count(*) from [User] where [Username]=@userName";
// string strAccessConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+this.Server.MapPath("PerInfo.mdb");
string strAccessConn = ConfigurationSettings.AppSettings["AccessConnection"]+this.Server.MapPath("PerInfo.mdb");
OleDbConnection AccessCon=new OleDbConnection(strAccessConn);
OleDbCommand comm = new OleDbCommand();
comm.Connection = AccessCon;
comm.Connection.Open();
comm.CommandType = CommandType.Text;
comm.CommandText = strSql;
comm.Parameters.Add("@userName",OleDbType.Char,16);
comm.Parameters["@userName"].Value=Uid.Text.ToString();
comm.ExecuteNonQuery();
if(Convert.ToInt32(comm.ExecuteScalar().ToString())>0)//ExecuteScalar() 返回数据库中第一行第一列的值
{
Uid.Text="";
Pwd.Text="";
PwdOk.Text="";
Page.RegisterStartupScript("msgbox","<script language=javascript>alert('dfgfg')</script>");
}
else
{

}

[tl_pear]

确定一下，是哪一句出错！
Try
Me.Text = "正在验证...."
Me.Cursor = System.Windows.Forms.Cursors.WaitCursor
Dim comstr As String
Dim mydataset As New DataSet
comstr = "select 密码 from 一般用户 where 用户名='" & Trim(TxtUserName.Text) & "'"
mydataset.Clear()
Dim adapter As New SqlDataAdapter(comstr, SqlConnection1)
adapter.Fill(mydataset, "table1") '判断密码是否正确

try

If mydataset.Tables("table1").Rows(0).Item(0).tostring = Trim(TxtPassword.Text) Then
'如果查找不到任何行，则此处出现异常
UserInf(0) = Trim(TxtUserName.Text)
UserInf(1) = CmbPurview.Text
If CmbPurview.Text <> "管理员" Then
With ob_MainForm
.BtGoods.Visible = False
.BtFinance.Visible = False
.BtEmployee.Visible = False
.BtSaleHistory.Visible = False
End With
End If
ob_MainForm.Show()
Catch ex As Exception
MsgBox("用户不存在!", MsgBoxStyle.OKOnly, "提示")
TxtUserName.Text = ""
TxtPassword.Text = ""
Me.Text = ""
Me.Cursor = System.Windows.Forms.Cursors.Arrow

end try
Me.Hide()
Else
MsgBox("密码错误!")
TxtPassword.Text = ""
Me.Text = ""
Me.Cursor = System.Windows.Forms.Cursors.Arrow
TxtPassword.Focus()

End If
Catch ex As Exception
msgbox(ex.message)
Me.Cursor = System.Windows.Forms.Cursors.Arrow

End Try

[hjh1982]

if mySet.Tables("add").Rows.Count>0 then
看看吧

[titan90]

这种情况用DATAREADER合适

[海大富运动]

不好意思，这么晚才来道谢！不过我不知道怎么调试，我是新手，做了一个断点，也不知道怎么调试！在sql的查询分析器里可以检索出所有数据的

[海大富运动]

还有没有人帮忙！

[海大富运动]

也没有提示出错！就是开始验证后跳到catch语句提示说没有该用户

[fkl711]

登陆按钮事件
strID = Trim(Me.TextBox1.Text)
If strID = "" Then
Me.Label1.Text = "请输入登录的用户名称。"
Exit Sub
End If
pwd = Trim(Me.TextBox2.Text)
sqlstr = "SELECT * FROM userinf WHERE (user = '" & strID & "')"
DS = New DataSet
DS.Clear()
DS = GetDataFromDB(sqlstr)
If DS.Tables(0).Rows.Count > 0 Then
sqlstr = "SELECT * FROM userinf WHERE " & _
"(user = '" & strID & "') AND (password = '" & pwd & "')"
Dim myDs As DataSet
myDs = New DataSet
myDs.Clear()
myDs = GetDataFromDB(sqlstr)
If myDs.Tables(0).Rows.Count > 0 Then
pepdom = myDs.Tables(0).Rows(0)("qx")
name = strID
‘------启动下一个窗体代码----
Dim frmAbout As New Form2
frmAbout.Show()
'---------------------------
Else
Me.Label1.Text = "输入的密码不正确，请重新输入密码。"
Me.TextBox2.Text = ""
End If
Else
Me.Label1.Text = "查无此人，请确认是否有该用户存在。"
Me.TextBox1.Text = ""
Me.TextBox2.Text = ""
End If
End Sub

[海大富运动]

谢谢这位大哥了！

[vb_vs]

because you dinnot update your datagrid or database

[winlmh]

select 密码 from 一般用户 where 用户名='" & Trim(TxtUserName.Text) & "'"
你根本就沒有讀出用戶名這個字段，改成

select 密码,用戶名 from 一般用户 where 用户名='" & Trim(TxtUserName.Text) & "'"