I'm trying to display information on a piece of equipment the idea is that the user will type in an ID in the textbox and it will display the information on a grid view:
Dim ID As String = TxtSearch.Text
Dim cmd As SqlCommand
Dim ds As String = "Select * from Medical_Equipment where AssetID='" & ID & "''"
Dim strConnString As String = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString
Dim con As New SqlConnection(strConnString)
cmd = New SqlCommand(ds, con)
Try
con.Open()
GridView1.EmptyDataText = "No equipment with that Asset ID"
GridView1.DataSource = cmd.ExecuteReader()
GridView1.DataBind()
Catch ex As Exception
Throw ex
Finally
con.Close()
con.Dispose()
End Try
End Sub
But it is not displaying the information Unclosed quotation mark after the character string '1001''.Incorrect syntax near '1001''
If AssetID is defined as numeric at database level the SQL statement should be:
"SELECT * FROM Medical_Equipment WHERE AssetID=" & ID
If it is defined as text then should be:
"SELECT * FROM Medical_Equipment WHERE AssetID='" & ID & "'"
I think you have a typo here:
Try this:
"Select * from Medical_Equipment where AssetID='" & ID & "'"
Related
This is my first time writing in VB.Net for aspx pages.
The problem I having is that the parameter is not going into the query at the line for cmd.Parameters.Add.
The error I am getting is
No value given for one or more required parameters.
on the line
reader = cmd.ExecuteReader;
I have tried:
Adding the PARAMETERS at the top of the query like I have shown;
Removing and Adding [] around the parameter;
Changing OleDbType.Integer to OleDbType.SmallInt or OleDbType.BigInt
I know the query works as I can place it into MS Access and will run once I add the parameter. But not when I run it in Visual Studio.
Dim reader As OleDbDataReader
Dim cmd As OleDbCommand
Dim SQL As String = "PARAMETERS [#ID] Long; " &
"SELECT tblField.FieldName, " &
"tblField.FieldCaption, " &
"tblField.FieldMinCharNum, " &
"tblField.FieldMaxCharNum, " &
"tblField.FieldDefault, " &
"tblField.FieldSection, " &
"tblField.FirstQuestion, " &
"tblField.FieldDescription, " &
"tblField.FieldRegEx " &
"FROM tblField " &
"WHERE tblField.FieldID = [#ID];"
cmd = New OleDbCommand(SQL, Connection.Connection)
cmd.Parameters.Add("[#ID]", OleDbType.Integer).Value = ID
reader = cmd.ExecuteReader
I have a work around to make it work by just pre-inserting the parameter into the SQL string. But I want to make this work for other areas of the page that are yet to be written. Where user inputs are coming back into database so inputs are sanitised.
OLEDB doesn't use # to identify parameters. It uses ? and allocates parameters in the order they appear in the SQL amend your code to...
Dim reader As OleDbDataReader
Dim cmd As OleDbCommand
Dim SQL As String = "SELECT tblField.FieldName, " &
"tblField.FieldCaption, " &
"tblField.FieldMinCharNum, " &
"tblField.FieldMaxCharNum, " &
"tblField.FieldDefault, " &
"tblField.FieldSection, " &
"tblField.FirstQuestion, " &
"tblField.FieldDescription, " &
"tblField.FieldRegEx " &
"FROM tblField " &
"WHERE tblField.FieldID = ?"
cmd = New OleDbCommand(SQL, Connection.Connection)
cmd.Parameters.Add("?", OleDbType.Integer).Value = ID
reader = cmd.ExecuteReader
I don't understand why your mentioning SQL are you retrieving the data from SQL Query or are you going to insert data into the table.
your using Dim cmd As OleDbCommand means use to insert the input values into the database like see below sample code.
query = "INSERT INTO ds.students (ID,NAME,PIC)" & _
"VALUES (#ID,#NAME,#PIC);"
Dim cmd As OracleCommand = New OracleCommand(query, con)
cmd.Parameters.Add("#ID", Convert.ToInt32(TextBox1.Text))
cmd.Parameters.Add("#NAME", Convert.ToString(TextBox2.Text))
cmd.Parameters.Add("#PIC", arrImage)
con.Open()
cmd.ExecuteNonQuery()
con.Close()
you can try this also
Using cn As OracleConnection = New OracleConnection(connectionString)
cn.Open()
Using cmd As OracleCommand = New OracleCommand()
Const sql As String = "Insert into test_table (val1, val2) values (:var1, :var2)"
cmd.Connection = cn
cmd.Parameters.Add(New OracleParameter("var1", TxtField1.Text))
cmd.Parameters.Add(New OracleParameter("var2", TxtField2.Text))
cmd.CommandText = sql
cmd.ExecuteNonQuery()
End Using
End Using
if you want to insert the values into the database change your code according to given samples.
Hope this will help you.
I have been working on this particular issue for a couple of days, and scouring over SO, MSDN and other google searches has not proven to be of any use. I am trying to make a simple update to a SQL table. My SELECT and INSERT statements all work fine, but for some reason, this update will not work. I have set breakpoints and stepped through, and the code seems to be working fine -- the Catch ex as Exception is never reached after the .ExecuteNonQuery() fires off.
Could anyone give me an idea of why I've been unable to get a SQL update?
Protected Sub SaveButton_Click(sender As Object, e As EventArgs) Handles SaveButton.Click
Dim currentUser = Membership.GetUser(User.Identity.Name)
Dim username As String = currentUser.UserName
Dim userId As Guid = currentUser.ProviderUserKey
UserNameTextBox.Text = username
' Get Root Web Config Connection String so you don't have to encrypt it
Dim rootWebConfig As System.Configuration.Configuration
rootWebConfig = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~/")
Dim connString As System.Configuration.ConnectionStringSettings
connString = rootWebConfig.ConnectionStrings.ConnectionStrings("LocalSqlServer")
Dim conn As String = connString.ToString
Dim commandString As String = "UPDATE UserDetails SET FirstName ='" + FirstNameTextBox.Text + "' WHERE UserId ='" + userId.ToString + "'"
Dim fname As String = FirstNameTextBox.Text
Dim commandText As String = "UPDATE UserDetails SET FirstName=#firstname WHERE UserId=#UID;"
Using connection As New SqlConnection(conn)
Dim command As New SqlCommand(commandText, connection)
command.CommandType = CommandType.Text
' Add UserId parameter for WHERE clause.
command.Parameters.Add("#UID", SqlDbType.UniqueIdentifier).Value = userId
' command.Parameters("#UID").Value = userId
' command.Parameters.AddWithValue("#UID", userId)
' Use AddWithValue to assign Demographics.
command.Parameters.Add("#firstname", SqlDbType.VarChar, 255).Value = fname
'command.Parameters.AddWithValue("#firstname", fname)
' command.Parameters("#firstname").Value = FirstNameTextBox.Text.ToString
Try
connection.Open()
command.ExecuteNonQuery()
Dim rowsAffected As Integer = command.ExecuteNonQuery()
Console.WriteLine("RowsAffected: {0}", rowsAffected)
Catch ex As Exception
Console.WriteLine(ex.Message)
Finally
connection.Close()
End Try
End Using
End Sub
You're running "command.ExecuteNonQuery()" twice, meaning the second execution will likely return 0 rows affected since you already updated what you needed to update, and that's what you're assigning to rowsAffected. Are you sure the UPDATE isn't occurring?
Edit: Re your comment, did you check for IsPostBack when you LoadUser? If not, when you click SaveButton, you're going to reload the existing values, and then you'll be updating with those existing values.
I'm trying to send an activation email and have the user activate their account by clicking on the link provided. I have been tweaking it based on open source code I've been looking at online, however it has recently stopped sending the email without giving any errors. Here is the sign up form with the send email function:
Imports System.Data.SqlClient
Imports System.Data.Sql
Imports System.Data.SqlTypes
Imports System.Data
Imports System.Configuration
Imports System.Net.Mail
Imports System.Net
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Public Class WebForm1
Inherits System.Web.UI.Page
Dim boolCar As Object
Private Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
If txtEmailAddress.Text.Trim.EndsWith("#umary.edu") Or txtPassword.Text.Trim = txtRetypePassword.Text.Trim Then
Dim con As New SqlConnection
Dim cmdEmail As New SqlCommand
Dim cmdRegistration As New SqlCommand
Dim EmailCount As Integer = 0
Try
con.ConnectionString = "Data Source=SERVERNAME;Initial Catalog=StudentGov;User ID=sa;Password=Password1"
con.Open()
cmdEmail = New SqlCommand("SELECT COUNT(UMaryEmail) As EmailCount FROM RegisteredUsers WHERE UMaryEmail='" & txtEmailAddress.Text.Trim & "'", con)
EmailCount = cmdEmail.ExecuteScalar()
If EmailCount = 0 Then
' Declare database input variables
Dim userId As Integer = 0
Dim firstName As String = txtFirstName.Text
Dim lastName As String = txtLastName.Text
Dim hometown1 As String = txtHometown1.Text
Dim state1 As String = txtState1.Text
Dim zip1 As String = txtZipCode1.Text
Dim hometown2 As String = txtHometown2.Text
Dim state2 As String = txtState2.Text
Dim zip2 As String = txtZipCode2.Text
Dim phoneNum As String = txtPhoneNumber.Text
Dim emailAddress As String = txtEmailAddress.Text
Dim password As String = txtPassword.Text
Dim boolCar As Boolean = False
Dim boolUmary As Boolean = False
If radYesNo.SelectedIndex = 0 Then
boolCar = True
Else
boolCar = False
End If
' Define the command using parameterized query
cmdRegistration = New SqlCommand("INSERT INTO RegisteredUsers(FirstName, LastName, Hometown1, State1, ZIP1, Hometown2, State2, ZIP2, PhoneNum, UMaryEmail, Password, Car) VALUES (#txtFirstName, #txtLastName, #txtHometown1, #txtState1, #txtZipCode1, #txtHometown2, #txtState2, #txtZipCode2, #txtPhoneNumber, #txtEmailAddress, #txtPassword, #RadYesNo)", con)
' Define the SQL parameter '
cmdRegistration.Parameters.AddWithValue("#txtFirstName", txtFirstName.Text)
cmdRegistration.Parameters.AddWithValue("#txtLastName", txtLastName.Text)
cmdRegistration.Parameters.AddWithValue("#txtHometown1", txtHometown1.Text)
cmdRegistration.Parameters.AddWithValue("#txtState1", txtState1.Text)
cmdRegistration.Parameters.AddWithValue("#txtZipCode1", txtZipCode1.Text)
cmdRegistration.Parameters.AddWithValue("#txtHometown2", txtHometown2.Text)
cmdRegistration.Parameters.AddWithValue("#txtState2", txtState2.Text)
cmdRegistration.Parameters.AddWithValue("#txtZipCode2", txtZipCode2.Text)
cmdRegistration.Parameters.AddWithValue("#txtPhoneNumber", txtPhoneNumber.Text)
cmdRegistration.Parameters.AddWithValue("#txtEmailAddress", txtEmailAddress.Text)
cmdRegistration.Parameters.AddWithValue("#txtPassword", txtPassword.Text)
cmdRegistration.Parameters.AddWithValue("#RadYesNo", boolCar)
cmdRegistration.ExecuteNonQuery()
SendActivationEmail(userId)
Response.Redirect("RegistrationSuccess.aspx")
Else
' Duplicate Email Exist Error Message
MsgBox("Email address already supplied.")
End If
' Catch ex As Exception (Not needed)
' Error Executing One Of The SQL Statements
Finally
con.close()
End Try
Else
' Throw Error Message
MsgBox("Email input error")
End If
End Sub
Private Sub SendActivationEmail(userId As Integer)
Dim sqlString As String = "Server=SERVERNAME;Database=StudentGov;UId=sa;Password=Password1;"
Dim ActivationCode As String = Guid.NewGuid().ToString()
Dim ActivationUrl As String = Server.HtmlEncode("http://localhost:63774/ActivateAccount.aspx?userId=" & FetchUserId(txtEmailAddress.ToString) & "&txtEmailAddress=" & txtEmailAddress.ToString & "&ActivationCode=" & ActivationCode.ToString)
Using con As New SqlConnection(sqlString)
Using sqlCmd As New SqlCommand("UPDATE RegisteredUsers SET UserId = '" + userId.ToString + "', ActivationCode = '" + ActivationCode.ToString + "' WHERE UMaryEmail='" + txtEmailAddress.Text + "';")
Using sda As New SqlDataAdapter()
sqlCmd.CommandType = CommandType.Text
sqlCmd.Parameters.AddWithValue("#UserId", userId)
sqlCmd.Parameters.AddWithValue("#ActivationCode", ActivationCode)
sqlCmd.Connection = con
con.Open()
sqlCmd.ExecuteNonQuery()
con.Close()
End Using
End Using
End Using
Using mm As New MailMessage("****#outlook.com", txtEmailAddress.Text)
mm.Subject = "Account Activation"
Dim body As String = "Hello " + txtFirstName.Text.Trim() + ","
body += "<br /><br />Please click the following link to activate your account"
body += "<br /><a href='" & ActivationUrl & "'>Click here to activate your account.</a>"
body += "<br /><br />Thanks"
mm.Body = body
mm.IsBodyHtml = True
Dim smtp As New SmtpClient()
smtp.Host = "smtp.live.com"
smtp.EnableSsl = True
Dim NetworkCred As New NetworkCredential("****#outlook.com", "****")
smtp.UseDefaultCredentials = True
smtp.Credentials = NetworkCred
smtp.Port = 587
Try
smtp.Send(mm)
Catch ex As Exception
MsgBox("Email was not sent")
End Try
End Using
End Sub
Private Function FetchUserId(emailAddress As String) As String
Dim cmd As New SqlCommand()
Dim con As New SqlConnection("Data Source=SERVERNAME;Initial Catalog=StudentGov;User ID=sa;Password=Password1")
cmd = New SqlCommand("SELECT UserId FROM RegisteredUsers WHERE UMaryEmail=#txtEmailAddress", con)
cmd.Parameters.AddWithValue("#txtEmailAddress", emailAddress)
If con.State = ConnectionState.Closed Then
con.Open()
End If
Dim userId As String = Convert.ToString(cmd.ExecuteScalar())
con.Close()
cmd.Dispose()
Return userId
End Function
End Class
And here is the AccountActivation page:
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration
Public Class ActivateAccount
Inherits System.Web.UI.Page
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
ActivateMyAccount()
End If
End Sub
Private Sub ActivateMyAccount()
Dim con As New SqlConnection()
Dim cmd As New SqlCommand()
Try
con.ConnectionString = "Data Source=CISWEB\UMCISSQL2008;Initial Catalog=StudentGov;User ID=sa;Password=Password1"
If (Not String.IsNullOrEmpty(Request.QueryString("UserId"))) And (Not String.IsNullOrEmpty(Request.QueryString("UMaryEmail"))) Then
'approve account by setting Is_Approved to 1 i.e. True in the sql server table
cmd = New SqlCommand("UPDATE RegisteredUsers SET AccountActivated=1 WHERE UserId=#UserId AND UMaryEmail=#txtEmailAddress", con)
cmd.Parameters.AddWithValue("#UserId", Request.QueryString("UserId"))
cmd.Parameters.AddWithValue("#txtEmailAddress", Request.QueryString("UMaryEmail"))
If con.State = ConnectionState.Closed Then
con.Open()
End If
cmd.ExecuteNonQuery()
Response.Write("You account has been activated. You can <a href='SignIn.aspx'>Sign in</a> now! ")
End If
Catch ex As Exception
ScriptManager.RegisterStartupScript(Me, Me.[GetType](), "Message", "alert('Error occured : " & ex.Message.ToString() & "');", True)
Return
Finally
con.Close()
cmd.Dispose()
End Try
End Sub
End Class
As you may be able to tell already, I am flummoxed. With no error messages I'm receiving, I don't know why the SendActivationEmail function is no longer working. Someone help please! :(
Hi FlummoxedUser are you sure that have you checked your code as well ????
Take a look here :
Dim ActivationUrl As String = Server.HtmlEncode("http://localhost:63774/ActivateAccount.aspx?userId=" & FetchUserId(txtEmailAddress.ToString) & "&txtEmailAddress=" & txtEmailAddress.ToString & "&ActivationCode=" & ActivationCode.ToString)
I think is better use httputility.urlEncode/Decode for this stuff where it use it to filter only the result of each function or single variable.
Second one take care at your code above
this is in your page :
If (Not String.IsNullOrEmpty(Request.QueryString("UserId"))) And (Not String.IsNullOrEmpty(Request.QueryString("UMaryEmail")))
where have you found "UmaryEmail" key in your querystring parameters?????
Check it and you will solve your issue but check also in cmd and so on in activation page or you will make some issues :)
I hope it help you and if it solves your issue mark this as answer.
UPDATE :
> Dim ActivationUrl As String = Server.HtmlEncode("http://localhost:63774/ActivateAccount.aspx?userId=" & FetchUserId(txtEmailAddress.ToString) & "&txtEmailAddress=" & txtEmailAddress.ToString & "&ActivationCode=" & ActivationCode.ToString)
with this task you create yout activation link which will be something like
http://localhost:63774/ActivateAccount.aspx?userId=1&txtEmailAddress=email#pippo&ActivationCode=123456
Now what's append when click on that link server handle request and create a collection data which include all the keys within your querystring
In effect you can use request.QueryString to check/retrieve values from each keys. So you can use as you did request.Querystring("keyname") to get the value for that particular parameter BUT in your case you check for a key which are not passed into the link. Pay attention that you have setup only 3 keys which are
UserID
txtEmailAddress
ActivationCode
there's no "UMaryEmail" key in request query string
Also another important stuff NEVER PASS IN QUERY STRING DATABASE FIELD :) use fantasy name or shortname which not reflect database field
example :
UserID => uid
ActivatioCode = token,acd,cd or anything you want
txtEmailAddress= email, em or any other name
Now activation page issue when you try to check your value use an if statement where check for userid key and UMaryEmail where userid could be matched coz it exist in query string but UmaryEmail is not into the request.querystring you have not provided it so if fails and nothing has been shown in page.
Here your Activation Sub revisited with some comments to better understand :
Private Sub ActivateMyAccount()
'Checking you keys in querystring
If Request.QueryString.AllKeys.Contains("Userid") AndAlso Request.QueryString.AllKeys.Contains("txtEmailAddress") Then
'here we assume that keys exist and so we can proceed with rest
If (Not String.IsNullOrEmpty(Request.QueryString("UserId"))) And (Not String.IsNullOrEmpty(Request.QueryString("txtEmailAddress"))) Then
'no we can proceed to make other stuff
'Another stuff place you connection string within connection string section in webconfig in order to make a simple request like this one :
'classic example for create a connection with web config file
' Using con As New SqlConnection(ConfigurationManager.ConnectionStrings("yourconnectionstringname").ToString)
Using con As New SqlConnection("Data Source=CISWEB\UMCISSQL2008;Initial Catalog=StudentGov;User ID=sa;Password=Password1")
If con.State = ConnectionState.Closed Then con.Open()
Dim sqlQuery As String = "UPDATE RegisteredUsers SET AccountActivated=1 WHERE UserId=#UserId AND UMaryEmail=#txtEmailAddress"
Using cmd As New SqlCommand(sqlQuery, con)
Try
With cmd
.Parameters.AddWithValue("#UserId", Request.QueryString("UserId"))
.Parameters.AddWithValue("#txtEmailAddress", Request.QueryString("txtEmailAddress"))
.ExecuteNonQuery()
Response.Write("You account has been activated. You can <a href='SignIn.aspx'>Sign in</a> now! ")
End With
Catch ex As Exception
ScriptManager.RegisterStartupScript(Me, Me.[GetType](), "Message", "alert('We apologize but something is gone wrong;our techs are checking the issue.Best regards etc etc etc');", True)
End Try
End Using
End Using
Else
Response.Write("<h1>invalid activation links!!</h1>")
End If
Else
Response.Write("<h1>invalid activation links!!</h1>")
End If
End Sub
If your query is right it should work at first shot :)
Take a try and let me know and if it solve your issue please mark it as answer
UPDATE 2:
Your actual code is :
Dim ActivationUrl As String = Server.HtmlEncode("localhost:63774/ActivateAccount.aspx?userId=" & HttpUtility.UrlEncode(FetchUserId(txtEmailAddress.ToString)) & "&txtEmailAddress=" & HttpUtility.UrlEncode(txtEmailAddress.ToString) & "&ActivationCode=" & HttpUtility.UrlEncode(ActivationCode.ToString))
But is all wrong let me explain:
Declar your variable : Dim ActivationUrl as string it is ok
Then built url so :
="http://localhost:63774/ActivateAccount.aspx?userId=" & HttpUtility.UrlEncode(FetchUserId(txtEmailAddress.text.tostring)) & "&txtEmailAddress=" & HttpUtility.UrlEncode(txtEmailAddress.text.tostring) & "&ActivationCode=" & HttpUtility.UrlEncode(ActivationCode.ToString))
Where take a look to piece of code which is your : 'HttpUtility.UrlEncode(txtEmailAddress.ToString)' in this manner you are passing a value system type object which is a textbox to pass textbox value you need to access to its .Text property like txtEmailAddress .Text
Change as per my code above and it will work (if your procedure is right)
**UPDATE CODE 3 **
Change your code with this.§be carefull don't change anything copy and paste all ActivateMyAccount Sub and delete your old one
Private Sub ActivateMyAccount()
'Checking you keys in querystring
If Request.QueryString.AllKeys.Contains("userId") And Request.QueryString.AllKeys.Contains("txtEmailAddress") Then
'here we assume that keys exist and so we can proceed with rest
If (Not String.IsNullOrEmpty(Request.QueryString("userId"))) And (Not String.IsNullOrEmpty(Request.QueryString("txtEmailAddress"))) Then
'no we can proceed to make other stuff
'Another stuff place you connection string within connection string section in webconfig in order to make a simple request like this one :
'classic example for create a connection with web config file
' Using con As New SqlConnection(ConfigurationManager.ConnectionStrings("yourconnectionstringname").ToString)
Using con As New SqlConnection("Data Source=CISWEB\UMCISSQL2008;Initial Catalog=StudentGov;User ID=sa;Password=Password1")
If con.State = ConnectionState.Closed Then con.Open()
Dim sqlQuery As String = "UPDATE RegisteredUsers SET AccountActivated=1 WHERE UserId=#UserId AND UMaryEmail=#txtEmailAddress"
Using cmd As New SqlCommand(sqlQuery, con)
Try
With cmd
cmd.Parameters.AddWithValue("#UserId", Request.QueryString("userId"))
cmd.Parameters.AddWithValue("#txtEmailAddress", Request.QueryString("txtEmailAddress"))
cmd.ExecuteNonQuery()
Response.Write("You account has been activated. You can <a href='SignIn.aspx'>Sign in</a> now! ")
End With
Catch ex As Exception
ScriptManager.RegisterStartupScript(Me, Me.[GetType](), "Message", "alert('We apologize but something is gone wrong;our techs are checking the issue.Best regards etc etc etc');", True)
End Try
End Using
End Using
Else
Response.Write("<h1>invalid activation links!! bad query string</h1>")
End If
Else
Response.Write("<h1>invalid activation links!! bad not string</h1>")
End If
End Sub
I'm writing a project and at the some point i have to check if there is an entry in database which matches the content of id-textbox and password-textbox. But I don't know how to indicate in my backend code(VB) that the query returns nothing.
This is the code I am using. But it doesn't work somehow. Error messages Are not being prompt:
Try
myconn.Open()
Dim stquery As String = "SELECT * from accountstbl WHERE user_ID = " & IdNumb.Text
Dim smd As MySqlCommand
Dim myreader As MySqlDataReader
smd = New MySqlCommand(stquery, myconn)
myreader = smd.ExecuteReader()
If myreader.Read() = True Then
If myreader.Item("user_ID") = IdNumb.Text Then
If myreader.Item("password") = CurrPass.Text Then
'some code if the user input is valid
Else
errorPassID.Visible = True
End If
Else
errorPassC.Visible = True
End If
End If
myconn.Close()
Catch ex As Exception
Dim ErrorMessage As String = "alert('" & ex.Message.ToString() & "');"
Page.ClientScript.RegisterStartupScript(Me.GetType(), "ErrorAlert", ErrorMessage, True) myconn.Close()
End Try
Will appreciate any help or suggestion.
I will try to check if the reader return rows and if not, emit an error message.
Also, do not use string concatenation to build queries, use always parametrized queries
myconn.Open()
Dim stquery As String = "SELECT * from accountstbl WHERE user_ID = #id"
Dim smd = New MySqlCommand(stquery, myconn)
smd.Parameters.AddWithValue("#id", Convert.ToInt32(IdNumb.Text))
Dim myreader = smd.ExecuteReader()
if Not myreader.HasRows Then
Dim ErrorMessage As String = "alert('No user found');"
Page.ClientScript.RegisterStartupScript(Me.GetType(), "ErrorAlert", ErrorMessage, True)
myconn.Close()
return
else
myreder.Read()
' no need to check if id is equal, you pass it as parameter to a where clause'
If myreader.Item("password") = CurrPass.Text Then
'some code if the user input is valid '
Else
errorPassID.Visible = True
' or error message '
End If
End If
myconn.Close()
Catch ex As Exception
Dim ErrorMessage As String = "alert('" & ex.Message.ToString() & "');"
Page.ClientScript.RegisterStartupScript(Me.GetType(), "ErrorAlert", ErrorMessage, True)
myconn.Close()
End Try
Note also that passing a clear text password along the wire is a serious security hole. I hope you have stored an hash of the password and check on that instead.
By the way, why don't pass also the password hash in the query? Somthing like this:
Dim stquery As String = "SELECT * from accountstbl WHERE user_ID = #id AND password = #pwd"
In this way, if you have a record returned the user is validated and your client side code will be simple
I have a form which goes to the following login script when it is submitted.
<%
Dim myConnection As System.Data.SqlClient.SqlConnection
Dim myCommand As System.Data.SqlClient.SqlCommand
Dim requestName As String
Dim requestPass As String
requestName = Request.Form("userName")
requestPass = Request.Form("userPass")
Dim queryString As String = "SELECT COUNT(*) AS Num_Of_User FROM tblusers WHERE username='" & requestName & "' AND password='" & requestPass & "'"
myConnection = New System.Data.SqlClient.SqlConnection("Data Source=(local);InitialCatalog=dbtest;Integrated Security=True")
myCommand = New System.Data.SqlClient.SqlCommand(queryString, myConnection)
myConnection.Open()
Dim reader As System.Data.SqlClient.SqlDataReader = myCommand.ExecuteReader()
%>
Now in theory, I should be able to get that Num_Of_User from the SQL Query and if it equals 1 than the login was successful. Is this the correct way? And how can I get the value that the SQL returns?
You are wide open to SQL injection using that code.
See happens if you enter the username as ' OR 2>1--
You need to change the to use a parametrized query.
Dim queryString As String = "SELECT COUNT(*) AS Num_Of_User FROM tblusers WHERE username=#username AND password=#password"
myConnection = New System.Data.SqlClient.SqlConnection("Data Source=(local);InitialCatalog=dbtest;Integrated Security=True")
myCommand = New System.Data.SqlClient.SqlCommand(queryString, myConnection)
myCommand.Parameters.AddWithValue("#username", requestName)
myCommand.Parameters.AddWithValue("#password", requestPass)
Also you are not handling any exceptions that might be thrown, nor disposing your objects.
Your code should look more like the following.
Dim numUsers as Integer
Using myConnection as New System.Data.SqlClient.SqlConnection("Data Source=(local);InitialCatalog=dbtest;Integrated Security=True")
Dim queryString As String = "SELECT COUNT(*) AS Num_Of_User FROM tblusers WHERE username=#username AND password=#password"
Using myCommand as New System.Data.SqlClient.SqlCommand(queryString, myConnection)
myConnection.Open
myCommand.Parameters.AddWithValue("#username", requestName)
myCommand.Parameters.AddWithValue("#password", requestPass)
numUsers = myCommand.ExecuteScalar()
End Using
End Using
The above code will make sure your objects are disposed, but won't handle any exceptions that might be thrown.
Try myCommand.ExecuteScalar(), which returns the value from the first column in the first row of the resultset - exactly the value you're after here.
Also, check into the ASP.Net 'built in' authentication methods - this might save you some effort.