Dim con As SqlConnection
con = New SqlConnection("server=chinna; uid=sa; pwd=136018#h; database=icms")
con.Open()
Dim cmd As SqlCommand
cmd = New SqlCommand("select pass from personal where idno=" & TextBox1.Text, con)
cmd.CommandType = CommandType.Text
Dim rdr As SqlDataReader
rdr = cmd.ExecuteReader
If rdr.Read() Then
TextBox2.Text = rdr.ToString()
Response.Redirect("default.aspx")
Else
MsgBox("incorrect password")
You need to use parameters in your query:
cmd = New SqlCommand("select pass from personal where idno=#param", con)
cmd.Parameters.AddWithValue("param", TextBox1.Text);
Use ExecuteScalar instead of ExecuteReader.
Dim password As String
password = cmd.ExecuteScalar.ToString()
FYI, storing passwords in plain text and comparing like this is VERY bad practice. You should be encrypting the passwords with some one-way salted encryption and then doing the same on verification then comparing the encrypted values.
You are missing the DataSource assignment.
Add GridView1.DataSource = rdr before you call DataBind.
Your If block should look like:
If rdr.Read() Then
GridView1.Visible = True
GridView1.DataSource = rdr
GridView1.DataBind()
End If
Should be
cmd = New SqlCommand("select pass from personal where idno='" & TextBox1.Text & "'", con)
beyond that code seems for ASP.net. We can not execute MsgBox in VB.net that can appear on client browser.
use HasRows on rdr and set DataSourcefor GridView1
Dim rdr As SqlDataReader
rdr = cmd.ExecuteReader()
If rdr.HasRows Then
GridView1.Visible = True
GridView1.DataSource = rdr
GridView1.DataBind()
End If
What is your error or are you just getting a null for rdr?
I don't see an outpout paramenter. You need one. You only have an input parameter.
You need to somehow mark that the user was logged in, using a Session variable or a login identity. Otherwise, anyone can go to the logged in version of the page by simply navigating directly to it.
MsgBox( is not valid in asp.net, because it would display a message on the server, not on the client. Try using a Label on the page to display error messages by setting its text.
What is the problem you are having? Does it just "not work"? Does it not validate your password correctly? Do you get an exception of some sort? Can you post the results?
Related
i am trying to get data from ms access database using this code but i can not this is my code is this correct
Dim query As String = "SELECT [data] FROM tabless WHERE user = '" & user.Text & "'"
Using connection As New OleDbConnection(connectionString)
Dim cmd As New OleDbCommand(query)
Dim adapter As OleDbDataAdapter = New OleDbDataAdapter(query, connection)
Dim com As New OleDbCommand(query, connection)
connection.Open()
'on the line below I get an error: connection property has not been initialized
Dim reader As OleDbDataReader = cmd.ExecuteReader()
While reader.Read()
Label1.Text = (reader(0).ToString())
End While
reader.Close()
End Using
Database
|data|
asl
trying to get data from database and trying to show it in a label is this possible
You never associated cmd with the connection, and you never use com or adapter. This is the sort of thing you can figure out by stepping through your code line by line and inspecting the state of it.
Dim query As String = "SELECT [data] FROM tabless WHERE user = '" & user.Text & "'"
Using connection As New OleDbConnection(connectionString)
Dim cmd As New OleDbCommand(query, connection)
connection.Open()
Dim reader As OleDbDataReader = cmd.ExecuteReader()
While reader.Read()
Label1.Text = (reader(0).ToString())
End While
reader.Close()
End Using
Also, your code is vulnerable to a SQL Injection Attack. You should not be concatenating strings together to form your queries. You should instead use parameterized queries.
So I have a label which shows the username of the user. I've used this value to return their ID which I then attach to a label. I used execute scalar to do this because I wasn't sure how else to get a single value on a label.
This works fine. I then use the ID from the label and put it in another table. I can do this twice and then the page crashes saying...
"Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression."
However I don't understand. I don't pull anything from the second table on the page. I don't know why it would affect it. I feel like I've tried everything. Taking out the line that posts the ID to the label lets the page run but I need it there.
Label2.Text = User.Identity.Name
Dim connetionString As String
Dim cnn As SqlConnection
Dim cmd As SqlCommand
Dim sql As String
connetionString = "Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\FYPMS_DB.mdf;Integrated Security=True"
sql = "SELECT SupID FROM Supervisor WHERE (Email = #Email)"
cnn = New SqlConnection(connetionString)
Try
cnn.Open()
cmd = New SqlCommand(sql, cnn)
cmd.Parameters.Add(New SqlParameter("#Email", User.Identity.Name))
Dim supid1 As Int32 = Convert.ToInt32(cmd.ExecuteScalar())
cmd.Dispose()
cnn.Close()
Label1.Text = supid1.ToString
Catch ex As Exception
MsgBox("Can not open connection ! ")
End Try
End Sub
This should return the first result for you. Also, it's a good idea to employ Using blocks for objects such as connections, commands, and readers.
Using cn = New SqlConnection("Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\FYPMS_DB.mdf;Integrated Security=True")
cn.Open()
Using cmd = New SqlCommand("SELECT SupID FROM Supervisor WHERE Email = #Email", cn)
cmd.Parameters.AddWithValue("#Email", User.Identity.Name)
Using dr = cmd.ExecuteReader
If dr.Read Then
Label1.Text = CInt(dr("SupID"))
End If
End Using
End Using
End Using
If you are not sure there are multiple rows for same email in that table, you can change the query to following, that will work for you with executescalar.
SELECT TOP 1 SupID FROM Supervisor WHERE (Email = #Email)
Horribly sorry! But yes you were right! There was another query going on in the background that I never noticed that was affecting it all. So sorry
I am trying to send some variables, using a session, to the next page "ProcedureSelectionForm.aspx". As you can see, the sessions have been commented out. The code below will work (without sending the variable of course). However, when you remove the comments the .onclick function reloads the page rather than navigating to "ProcedureSelectionForm.aspx". For this reason, I believe this is where my problem is. The first two columns are "Account" and "Password" in the database. I have not misspelled anything. I am new to VB and ASP.net and would appreciate some explanation as to what is happening and why my desired functionality isn't materializing. Thank you for your help!
If IsValid Then
Try
Dim strSQL = "select * from CreatePatient where Account = #Account and Password = #Password"
Using CCSQL = New SqlConnection(ConfigurationManager.ConnectionStrings("CreatePatientConnectionString").ConnectionString)
Using CCUser = New SqlCommand(strSQL, CCSQL)
CCSQL.Open()
CCUser.Parameters.Add("#Account", Data.SqlDbType.VarChar).Value = PatientAccount.Text
CCUser.Parameters.Add("#Password", Data.SqlDbType.VarChar).Value = PatientPass.Text
CCUser.ExecuteNonQuery()
'Using reader As SqlDataReader = CCUser.ExecuteReader()
'If reader.HasRows Then
'reader.Read()
'Session("user") = reader("Account")
'Session("pass") = reader("Password")
Response.Redirect("ProcedureSelectionForm.aspx")
'End If
'End Using
End Using
End Using
Catch ex As Exception
Label1.Text = ex.Message
End Try
End If
My friend was able to make time to help me out. I am unsure of what he did differently besides closing connections
If IsValid Then
Dim CCSQL As New SqlConnection
Dim CCUser As New SqlCommand
Dim strSQL As String
Dim dtrUser As SqlDataReader
Try
CCSQL.ConnectionString = ConfigurationManager.ConnectionStrings("CreatePatientConnectionString").ConnectionString
strSQL = "Select * from CreatePatient where Account=#user and Password=#pwd"
CCUser.CommandType = Data.CommandType.Text
CCUser.CommandText = strSQL
CCUser.Parameters.Add("#user", Data.SqlDbType.VarChar).Value = PatientAccount.Text
CCUser.Parameters.Add("#pwd", Data.SqlDbType.VarChar).Value = PatientPass.Text
CCSQL.Open()
CCUser.Connection = CCSQL
dtrUser = CCUser.ExecuteReader()
If dtrUser.HasRows Then
dtrUser.Read()
Session("user") = dtrUser("Account")
Session("level") = dtrUser("Password")
Response.Redirect("ProcedureSelectionForm.aspx")
Else
Label1.Text = "Please check your user name and password"
End If
dtrUser.Close()
CCSQL.Close()
Catch ex As Exception
Label1.Text = ex.Message
End Try
End If
I am on a tight deadline but i will get back to those interested with an answer. Thank you for your effort.
You don't want to do .ExecuteNonQuery() when you are actually doing a query (i.e. a SQL "SELECT" statement. You can just do the .ExecuteReader() to read those two values.
Also, I presume you are trying to validate the Account and Password; otherwise you could just set Session("user") = PatientAccount.Text and set Session("pass") = PatientPass.Text.
For the last 2 hours I was trying figure out why the parameter could not be bound (Well I know I was not using the "using" block. And I know System.Data.OracleClient is deprecated.) Please help me see what's wrong with the following code:
Dim nCount As Integer
sSQL = " SELECT COUNT(*) FROM USERS WHERE USER_ID = :UID "
Dim conn As OracleConnection = New OracleConnection(ConfigurationSettings.AppSettings("connString"))
conn.Open()
Dim cmd As OracleCommand = New OracleCommand(sSQL, conn)
cmd.CommandType = CommandType.Text
With cmd
.Parameters.Add(New OracleParameter(":UID", txtUserID.Text))
End With
Try
nCount = cmd.ExecuteScalar()
Catch ex As Exception
End Try
I have tried all variations I can find online: with or without colon in the Parameters.Add, Add or AddWithValue, Add in a parenthesis or create a new OracleParameter object then add it...Nothing seems to work.
But if I just hard-code the USER_ID in the query, remove the parameter.Add, it would return a value.
A HA!
UID is actually a reserved word in Oracle. Change your UID variable to something that is not a reserved word.
For me it seems that you missed something, while experimenting with different combinations.
This variant must work:
Dim nCount As Integer
sSQL = "SELECT COUNT(*) FROM USERS WHERE USER_ID = :UID"
Dim conn As OracleConnection = New OracleConnection(ConfigurationSettings.AppSettings("connString"))
conn.Open()
Dim cmd As OracleCommand = New OracleCommand(sSQL, conn)
cmd.CommandType = CommandType.Text
cmd.Parameters.Add("UID", OracleType.VarChar).Value = txtUserID.Text
nCount = cmd.ExecuteScalar()
Please try it ...
Do yourself a favor and at least look into ODP from Oracle. You'll need it with Microsoft finally pulls the plus on its OracleClient. The switch over to ODP is very easy.
In your situation, I'd leave off the parameter name. You're binding by position anyway.
The SQL syntax is also a little different in the Microsoft implementation. Use a ? to act as each placeholder. See http://msdn.microsoft.com/en-us/library/system.data.oracleclient.oracleparameter.aspx for further information.
I have this mySQL code that connects to my server. It connects just fine:
Dim MyConString As String = "DRIVER={MySQL ODBC 3.51 Driver};" & _
"SERVER=example.com;" & _
"DATABASE=xxx;" & _
"UID=xxx;" & _
"PASSWORD=xxx;" & _
"OPTION=3;"
Dim conn As OdbcConnection = New OdbcConnection(MyConString)
conn.Open()
Dim MyCommand As New OdbcCommand
MyCommand.Connection = conn
MyCommand.CommandText = "select * from userinfo WHERE emailAddress = '" & theUN & "'""
MyCommand.ExecuteNonQuery()
conn.Close()
However, i have an old Classic ASP page that uses "oRecordset" to get the data from the mySQL server:
Set oConnection = Server.CreateObject("ADODB.Connection")
Set oRecordset = Server.CreateObject("ADODB.Recordset")
oConnection.Open "DRIVER={MySQL ODBC 3.51 Driver}; SERVER=example.com; PORT=3306; DATABASE=xxx; USER=xxx; PASSWORD=xxx; OPTION=3;"
sqltemp = "select * from userinfo WHERE emailAddress = '" & theUN & "'"
oRecordset.Open sqltemp, oConnection,3,3
And i can use oRecordset as follows:
if oRecordset.EOF then....
or
strValue = oRecordset("Table_Name").value
or
oRecordset("Table_Name").value = "New Value"
oRecordset.update
etc...
However, for the life of me, i can not find any .net code that is similar to that of my Classic ASP page!!!!!
Any help would be great! :o)
David
This is what you have to do:
instead of MyCommand.ExecuteNonQuery you should use MyCommand.ExecuteQuery and assign it to DataReader.
Check out this sample:
Dim myConnection As SqlConnection
Dim myCommand As SqlCommand
Dim dr As New SqlDataReader()
'declaring the objects
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)_
Handles MyBase.Load
myConnection = New SqlConnection("server=localhost;uid=sa;pwd=;database=pubs")
'establishing connection. you need to provide password for sql server
Try
myConnection.Open()
'opening the connection
myCommand = New SqlCommand("Select * from discounts", myConnection)
'executing the command and assigning it to connection
dr = myCommand.ExecuteReader()
While dr.Read()
'reading from the datareader
MessageBox.Show("discounttype" & dr(0).ToString())
MessageBox.Show("stor_id" & dr(1).ToString())
MessageBox.Show("lowqty" & dr(2).ToString())
MessageBox.Show("highqty" & dr(3).ToString())
MessageBox.Show("discount" & dr(4).ToString())
'displaying the data from the table
End While
dr.Close()
myConnection.Close()
Catch e As Exception
End Try
HTH
Dim conn As OdbcConnection = New OdbcConnection("DRIVER={MySQL ODBC 3.51 Driver}; SERVER=xxx.com; DATABASE=xxx; UID=xxx; PASSWORD=xxx; OPTION=3;")
conn.Open()
Dim MyCommand As New OdbcCommand
MyCommand.Connection = conn
MyCommand.CommandText = "SELECT * FROM userinfo"
Dim rst = MyCommand.ExecuteReader()
While rst.Read()
response.write(rst("userID").ToString())
End While
conn.Close()
Dim email As String = "anyone#anywhere.com"
Dim stringValue As String
Using conn As OdbcConnection = New OdbcConnection(MyConString)
conn.Open()
Dim sql = "Select ... From userInfo Where emailAddress = #Email"
Using cmd As OdbcCommand = New OdbcCommand(sql, conn)
cmd.Parameters.AddWithValue("#Email", email)
Dim reader As OdbcDataReader = cmd.ExecuteReader()
While reader.Read()
stringValue = reader.GetString(0)
End While
End Using
conn.Close()
End Using
'To do an Update
Using conn As OdbcConnection = New OdbcConnection(MyConString)
conn.Open()
Dim sql As String = "Update userInfo Set Column = #Value Where PK = #PK"
Using cmd As OdbcCommand = New OdbcCommand(sql, conn)
cmd.Parameters.AddWithValue("#Email", email)
cmd.ExecuteNonQuery()
End Using
End Using
'To do an Insert
Using conn As OdbcConnection = New OdbcConnection(MyConString)
conn.Open()
Dim sql As String = "Insert userInfo(Col1,Col2,...) Values(#Value1,#Value2...)"
Using cmd As OdbcCommand = New OdbcCommand(sql, conn)
cmd.Parameters.AddWithValue("#Col1", value1)
cmd.Parameters.AddWithValue("#Col2", value2)
...
cmd.ExecuteNonQuery()
End Using
End Using
First, even in ASP Classic, it is an absolutely horrid approach to concatenate a value directly into a SQL statement. This is how SQL Injection vulnerabilities happen. You should always sanitize values that get concatenated into SQL statements. In .NET, you can use parametrized queries where you replace the values that go into your query with a variable that begins with an # sign. You then add a parameter to the command object and set your value that way. The Command object will sanitize the value for you.
ADDITION
You mentioned in a comment that your ASP Classic code is shorter. In fact, the .NET code is shorter because there are a host of things happening that you do not see and have not implemented in your ASP Classic code. I already mentioned one which is sanitizing the inputs. Another is logging. Out of the box, if an exception is thrown, it will log it in the Event Log with a call stack. To even get a call stack in ASP Classic is a chore much less any sort of decent logging. You would need to set On Error Resume Next and check for err.number <> 0 after each line. In addition, without On Error Resume Next, if an error is thrown, you have no guarantee that the connection will be closed. It should be closed, but the only way to know for sure is to use On Error Resume Next and try to close it.
Generally, I encapsulate all of my data access code into a set of methods so that I can simply pass the SQL statement and the parameter values and ensure that it is called properly each time. (This holds true for ASP Classic too).