Inserting VB.net Label to mysql table - mysql

How to Inserting Label.text data into mySql table.
i have no problem with textbox.text but i can't figure out how it with Label.text
i try the same code with textbox.text
parameterB_Answer.Value = TextBox1.Text
it work find but when i try with
parameterB_Answer.Value = Label1.Text
mySqlReader seems can't read it.
Update:
1.1.1 is label1.text. My Idea is to insert the text "1.1.1" from Label1 as Primary key and the Textbox(textbox1.text) as the following
my code is:
Try
Dim StrSQL As String = "INSERT INTO boranga" & _
"(IdBorangA,Answers)" & _
"VALUES (#B_IdA,#B_Answer);"
Dim myCommand As MySqlCommand = New MySqlCommand(StrSQL, conn.open)
myCommand.CommandType = CommandType.Text
Dim parameterB_IdA As MySqlParameter = New MySqlParameter("#B_IdA", MySqlDbType.VarChar, 300)
parameterB_IdA.Value = Label1.Text
Dim parameterB_Answer As MySqlParameter = New MySqlParameter("#B_Answer", MySqlDbType.VarChar, 300)
parameterB_Answer.Value = TextBox1.Text
With myCommand.Parameters
.Add(parameterB_IdA)
.Add(parameterB_Answer)
End With
Dim result As MySqlDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
MsgBox("Tersimpan", vbYes, "boranga")
Catch SqlEx As MySqlException
Throw New Exception(SqlEx.Message.ToString())
End Try
but when I change the value of Label1.text (1.1.1) to 111, it works just fine. probably because I put INT for the column for label1.text to fill while "1.1.1" isn't integer
thank a lot
PS:seems i can't post image because low of reputation

Try using this code format first of all:
Private Sub btnLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
Dim conn As MySqlConnection
'Connect to the database using these credentials
conn = New MySqlConnection
conn.ConnectionString = "server=your server site (generally long url); user id=login id for mysql user; password=self explanatory; database=name of the DB you're trying to reach"
'Try and connect (conn.open)
Try
conn.Open()
Catch myerror As MySqlException 'If it fails do this... (i.e. no internet connection, etc.)
MsgBox("Error connecting to database. Check your internet connection.", MsgBoxStyle.Critical)
End Try
'MySQL query (where to call for information)
Dim myAdapter As New MySqlDataAdapter
'Tell where to find the file with the emails/passes stored
Dim sqlquery = "SELECT * FROM the database you selected above WHERE Email = '" & txtEmail.Text & "' AND Password = '" & txtPassword.Text & "'"
Dim myCommand As New MySqlCommand
myCommand.Connection = conn
myCommand.CommandText = sqlquery
'Start query
myAdapter.SelectCommand = myCommand
Dim myData As MySqlDataReader
myData = myCommand.ExecuteReader
If myData.HasRows = 0 Then
MsgBox("Invalid email address or password.", MsgBoxStyle.Critical)
Else
MsgBox("Logged in as " & txtEmail.Text & ".", MsgBoxStyle.Information)
Me.Close()
End If
End Sub
And to insert label.text try replacing one of the textbox.text fields first and see if it will accept it. If it does, then the answer was all in the formatting.
Also, do not forget to call:
imports mysql.data.mysqlclient
and make sure to add the mysql.data reference.

Related

reading and comparing data values in MySQL database in vb.net

I'm trying to collect input from the user, check it against my database, and see if it exists in the database. If it does the program is supposed to fetch the last name, first name, and fees of the respective individual and output it.
Code:
Imports Mysql.Data.MySqlClient
Public Class Form1
Dim reader As MySqlDataReader
Dim command As New MySqlCommand
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myConnectionString As String
myConnectionString = "server=localhost;" _
& "uid=root;" _
& "pwd=Emma#21*GCTU;" _
& "database=dummystudents"
Try
Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
conn.Open()
Dim sql As String = "SELECT idstudents FROM students WHERE idstudents = #TextBox1.Text "
command = New MySqlCommand(sql, conn)
reader = command.ExecuteReader()
If reader.Read() Then
TextBox2.Text = reader(1)
TextBox3.Text = reader(2)
TextBox4.Text = reader(3)
End If
Catch ex As MySql.Data.MySqlClient.MySqlException
MessageBox.Show(ex.Message)
End Try
End Sub
End Class
Here's your SQL code:
SELECT idstudents FROM students WHERE idstudents = #TextBox1.Text
What's the point of pulling idstudents out when that's the value you're putting in? Worse, though, that's ALL you're pulling out, then you do this:
TextBox2.Text = reader(1)
TextBox3.Text = reader(2)
TextBox4.Text = reader(3)
which would require you to pull back at least four columns.
The modification mentioned in the comments may well get your code to execute but it's not the right way to go. It looks like you tried to use a parameter but failed. Do that but do it right, i.e.
Dim sql As String = "SELECT idstudents, otherColumnsHere FROM students WHERE idstudents = #idstudents"
Using connection As New MySqlConnection(myConnectionString),
command As New MySqlCommand(sql, connection)
command.Parameters.Add("#idstudents", MySqlDbType.Int32).Value = CInt(TextBox1.Text)
conn.Open()
Using reader = command.ExecuteReader()
If reader.Read() Then
TextBox2.Text = reader(1)
TextBox3.Text = reader(2)
TextBox4.Text = reader(3)
End If
End Using
End Using

How do I write to a Mysql database in VB.net with a query

I am trying to make a little program that writes and reads from a Mysql database. The reading part is going well, but I am a bit stuck in the write part.
This is my code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Absenden.Click
Dim conn As New MySqlConnection
Dim command As MySqlCommand
Dim myConnectionString As String
myConnectionString = "server=Nothing;uid=to;pwd=see;database=here;"
conn.ConnectionString = myConnectionString
Try
conn.Open()
Dim Querywrite As String
Querywrite = "select * FROM here.message INSERT INTO message admin='" & TB_Name.Text & "' and message='" & TB_Nachricht.Text & "' and Server='" & TB_Server.Text & "' and status='" & TB_Status.Text & "' "
command = New MySqlCommand(Querywrite, connection)
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
conn.Close()
End Sub
The Querywrite part is the problem I think. The input comes from Textboxes in a Windows Form.
Thanks for your help!
Perhaps, if someone shows you once then you will get the idea. The main thing is to always use parameters; not only will you avoid minor sytax and type errors but you will avoid major disasters of malicious input. I guessed at the datatypes of your fields. Please check your database for the types and adjust your code accordingly.
Private Sub InsertData()
Dim strQuery As String = "Insert Into message (admin, message, Server, status) Values (#admin, #message, #Server, #status);"
Using cn As New MySqlConnection("your connection string")
Using cmd As New MySqlCommand With {
.Connection = cn,
.CommandType = CommandType.Text,
.CommandText = strQuery}
cmd.Parameters.Add("#admin", MySqlDbType.VarString).Value = TB_Name.Text
cmd.Parameters.Add("#message", MySqlDbType.VarString).Value = TB_Nachricht.Text
cmd.Parameters.Add("#Server", MySqlDbType.VarString).Value = TB_Server.Text
cmd.Parameters.Add("#status", MySqlDbType.VarString).Value = TB_Status.Text
cn.Open()
cmd.ExecuteNonQuery()
cn.Close()
End Using
End Using
End Sub

Why do I keep getting this mysql error?

Hi stackoverflow people!
I have been recently developing a simple vb.net program that connects to a mysql database to register and login users with given credentials. I have used this code to register my users but I keep getting and error (below the code)
Dim insertUser As String = "INSERT INTO users(ID, username, password, email, verif)" _
& " VALUES('','" & Username.Text & "','" & Password.Text & "','" & Email.Text & "','" & currentRandString & "');"
Dim checkUsername As String = "SELECT * FROM users WHERE username='" & Username.Text & "'"
MysqlConn = New MySqlConnection()
MysqlConn.ConnectionString = mysqlconntxt4reg
MysqlConn.Open()
Dim myCommand As New MySqlCommand
myCommand.Connection = MysqlConn
myCommand.CommandText = checkUsername
myAdapter.SelectCommand = myCommand
Dim myData As MySqlDataReader
myData = myCommand.ExecuteReader
If myData.HasRows > 0 Then
MsgBox("Username Already In Use...", MsgBoxStyle.Critical, "Error")
myData.Close()
Else
myData.Close()
Dim myCommand2 As New MySqlCommand
myCommand2.Connection = MysqlConn
myCommand2.CommandText = insertUser
myAdapter.SelectCommand = myCommand2
Dim myData2 As MySqlDataReader
myData2 = myCommand2.ExecuteReader
Mail(Email.Text, currentRandString)
Me.Close()
myData2.Close()
End If
Catch myerror As MySqlException
MsgBox("Error While Connecting To Database:" & vbNewLine & vbNewLine & myerror.ToString, MsgBoxStyle.Critical, "Error")
Finally
MysqlConn.Dispose()
End Try
I have closed all my datareaders before opening other ones so I do not see why this does not work...
Error:
Link to Error Image
I would appreciate any help on this topic!
Thanks
Rodit
I would use the using statement around all the disposable objects to be sure that they release every references to the connection when they are no more needed, but looking at your code, I think you don't need at all the datareaders because you could resolve your problem just with the commands
Dim insertUser As String = "INSERT INTO users(username, password, email, verif)" _
& " VALUES(#p1, #p2,#p3,#p4)"
Dim checkUsername As String = "SELECT COUNT(*) FROM users WHERE username=#p1"
Using MysqlConn = New MySqlConnection(mysqlconntxt4reg)
Using myCommand = New MySqlCommand(checkUsername, MysqlConn)
MysqlConn.Open()
myCommand.Parameters.AddWithValue("#p1", Username.Text)
Dim result = myCommand.ExecuteScalar()
if result IsNot Nothing AndAlso Convert.ToInt32(result) > 0 Then
MsgBox("Username Already In Use...", MsgBoxStyle.Critical, "Error")
Else
Using myCommand2 = New MySqlCommand(insertUser, MysqlConn)
mycommand2.Parameters.AddWithValue("#p1",Username.Text)
mycommand2.Parameters.AddWithValue("#p2",Password.Text )
mycommand2.Parameters.AddWithValue("#p3",Email.Text)
mycommand2.Parameters.AddWithValue("#p4",currentRandString )
myCommand2.ExecuteNonQuery()
Mail(Email.Text, currentRandString)
End Using
End If
End Using
End Using
Of course I have replaced your string concatenations with a parameterized query. This is really an important thing to do to avoid Sql Injection
I have replaced the query that checks the user existence with a scalar operation that can be used with the command ExecuteScalar. Also, in the first query, it seems that you try to insert the field ID with an empty string. I think that the first field (ID) is an autonumber field and, in this case, you don't add it to the insert query and don't pass any value because the database will calculate that field for you.

MysqlException was unhandled DataReader with this connection must be closed vb.net

I have encountered this problem:
ERROR: There is already an open DataReader associated with this Connection which must be closed first.
Please have a look on my code:
Dim sqlQuery As String = "SELECT * FROM users"
Dim myAdapter As New MySqlDataAdapter
If txtUsername.Text = String.Empty And txtPassword.Text = String.Empty Then
MsgBox("Enter username and password", MsgBoxStyle.Exclamation, "Tea Sparkle POS")
Else
Dim sqlquerry = "Select * From users where username = '" + txtUsername.Text + "' And password= '" + txtPassword.Text + "'"
Dim myCommand As New MySqlCommand()
myCommand.Connection = SQLConnection
myCommand.CommandText = sqlquerry
'Starting The Query
myAdapter.SelectCommand = myCommand
Dim mydata As MySqlDataReader
mydata = myCommand.ExecuteReader()
'To check the Username and password and to validate the login a
If mydata.HasRows = 0 Then
MsgBox("Invalid Login")
txtPassword.Clear()
txtUsername.Clear()
Else
Dim authorityid = 0
While mydata.Read()
authorityid = mydata.GetInt32("authorityid")
End While
MsgBox("Welcome " + txtUsername.Text + "!")
If authorityid = 1 Then
MainForm.Show()
Else
MainForm.Show()
End If
Me.Hide()
End If
End If
Private Sub Login_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
SQLConnection.ConnectionString = ServerString
Try
If SQLConnection.State = ConnectionState.Closed Then
SQLConnection.Open()
Else
SQLConnection.Close()
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
This error is in this line:
mydata = myCommand.ExecuteReader()
What's wrong with this? Any help is truly appreciated.
What's wrong with this?
Well, it looks like you're reusing an existing connection:
myCommand.Connection = SQLConnection
Don't do that. Create a new connection each time you need to talk to the database, and close it when you've finished, using a Using statement to make sure it gets closed even if an exception is thrown.
Additionally, use a Using statement for your command, and another for your reader - these are all resources you should be closing.
Oh, and it also looks like you're doing this in the UI thread, which is a bad idea as your UI will be unresponsive while the database access is ongoing.

button not working when i insert new data

when I input data are not yet available. button does not work
but when I enter existing data in the database, the button work for find existing records in the database and msgbox.appear
this my coding. (i am using Microsoft Visual Basic 2008 express edition database mysql)
Imports MySql.Data.MySqlClient
Public Class Form2
Public conn As MySqlConnection
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Application.DoEvents()
Button1.Focus()
conn = New MySqlConnection
'conn.ConnectionString = "server=localhost;database=ilmu;userid=root;password= ''"
Try
conn.Open()
Catch ex As Exception
MessageBox.Show("Error1: " & ex.Message)
End Try
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
conn = New MySqlConnection("server=localhost;database=ilmu;userid=root;password= ''")
Try
conn.Open()
Dim sqlquery As String = "SELECT * FROM visitor WHERE nama = '" & TextBox1.Text & "';"
Dim data As MySqlDataReader
Dim adapter As New MySqlDataAdapter
Dim command As New MySqlCommand
command.CommandText = sqlquery
command.Connection = conn
adapter.SelectCommand = command
data = command.ExecuteReader
While data.Read()
If data.HasRows() = True Then
If data(2).ToString = TextBox2.Text Then
command = New MySqlCommand
command.Connection = conn
tkhupd = Now.ToString("yyyy-MM-dd HH:mm:tt")
command.CommandText = "INSERT INTO visitor(noK,khupd)VALUES ('" & TextBox1.Text & "','" & tkhupd & "')"
command.ExecuteNonQuery()
MessageBox.Show(" Berjaya, Sila Masuk. ", "Tahniah", MessageBoxButtons.OK, MessageBoxIcon.Information)
Else
MsgBox("exist")
End If
Else
MsgBox("Failed Login.")
End If
End While
Catch ex As Exception
End Try
End Sub
End Class
I am not sure what you are trying to do when there is not matching record in the database, but you don't have any code that would be hit in the case of no matching entries.
If there are no matching records, your while condition isn't met and nothing in the loop happens.
Fixing it likely involves rearranging the order of your loop and your if condition.
Check to see if data.hasRows first.
Example:
If data.HasRows() = True Then
While Data.Read
//code here for found rows
End While
Else
//code for no matching entries
End If
And as has been mentioned in Joel's comment, you really should look at using parameterized queries.
example of your insert command altered:
command.CommandText = "INSERT INTO visitor(noK,khupd)VALUES (?noK,?khupd)"
command.Parameters.AddWithValue("?noK",TextBox1.Text)
command.Parameters.AddWithValue("?khupd", tkhupd)
command.ExecuteNonQuery()