I'm having trouble trying to read from a MySQL databse using VB.NET, the error message I get is "ArgumentExcpetion was unhandled"
Also, the reading should return 'F', since this is the value allocated on that specific place on the table.
Imports MySql.Data.MySqlClient
Public Class Form1
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Application.Exit()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim query As String = "SELECT DO FROM klein WHERE COMMAND='DELETE'"
Dim connStr As String = "server=" & TextBox1.Text & ";" _
& "user id=" & TextBox2.Text & ";" _
& "password=" & TextBox3.Text & ";" _
& "database=hidro201_liberato"
Dim connection As New MySqlConnection(connStr)
Dim cmd As New MySqlCommand(query, connection)
connection.Open()
Dim reader As MySqlDataReader
reader = cmd.ExecuteReader()
While reader.Read()
TextBox4.Text = (reader.GetChar(1)) '<- **problem is here**
End While
End Sub
End Class
The field index is zero based.
TextBox4.Text = (reader.GetChar(0))
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.getchar.aspx
Parameter i: "The zero-based column ordinal."
You have only one column in your query and the index of the column should be zero
TextBox4.Text = (reader.GetChar(0))
This is for SqlServer but the rules are the same for a MySqlDataReader
TextBox4.Text = (reader.GetChar("Name of column to get the value"))
All the best
Related
Code :
Private m_cn As New SqlConnection
Private m_DA As SqlDataAdapter
Private m_CB As SqlCommandBuilder
Private m_DataTable As New DataTable
Private m_intRowPosition As Integer = 0
Private Sub InsertDatabaseItem_Load(sender As Object, e As EventArgs) Handles MyBase.Load
m_cn.ConnectionString = "Data Source=My-PC\SQLSERVEREXPRESS;Initial Catalog=ConvienienceProducts;Integrated Security=True"
m_cn.Open()
m_DA = New SqlDataAdapter("Select * From ProductIndex", m_cn)
m_CB = New SqlCommandBuilder(m_DA)
End Sub
Private Sub btnOK_Click(sender As Object, e As EventArgs) Handles btnOK.Click
Dim cmd As New SqlCommand(("INSERT INTO ProductIndex VALUES(" &
txtID.Text & "," &
txtName.Text & "," &
txtPrice.Text & "," &
txtDesc.Text & ")"), m_cn)
cmd.ExecuteNonQuery()
MsgBox("Success....", MsgBoxStyle.Information, "SUCCESS")
Me.Hide()
txtID.Clear()
txtName.Clear()
txtPrice.Clear()
txtDesc.Clear()
m_cn.Close()
m_cn.Dispose()
End Sub
Private Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.Click
Me.Hide()
End Sub
This is the error message :
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
Additional information: Incorrect syntax near ','.
You code should be using parameters. Try this:
Dim cmd As New SqlCommand(("INSERT INTO ProductIndex VALUES(" &
"#ID," &
"#Name," &
"#Price," &
"#Desc)"), m_cn)
cmd.Parameters.Add("#ID", SqlDbType.Char)
cmd.Parameters("#ID").Value = txtID.Text
cmd.Parameters.Add("#Name", SqlDbType.Char)
cmd.Parameters("#Name").Value = txtName.Text
cmd.Parameters.Add("#Price", SqlDbType.Char)
cmd.Parameters("#Price").Value = txtPrice.Text
cmd.Parameters.Add("#Desc", SqlDbType.Char)
cmd.Parameters("#Desc").Value = txtDesc.Text
The types are probably wrong (especially Price, and probably ID), but as you know what they are, and I don't, you can easily correct them.
You need to wrap your string values in single quotes
Dim cmd As New SqlCommand(("INSERT INTO ProductIndex VALUES('" & txtID.Text & "',
Hard to see but there is a single quote just before and after the double quotes surrounding your variables.
I have answered your particular question but you should be using parameters
Public Class Form5
Dim CrystalReportViewer1 As Object
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If TextBox1.Text = "thulasi" Then
Form3.Show()
Else
MsgBox("Incorrect password ! Try again", MsgBoxStyle.OkOnly, "Thulasi-Restaurent")
Exit Sub
End If
Me.Close()
Dim ds As New DataSet
Dim str As String
str = "select * from billall where bdate between #" & DateTimePicker1.Value.Date & "# and #" & DateTimePicker2.Value.Date & "# order by indate"
Cn.Open()
Dim adap As New OleDbDataAdapter(str, Cn)
adap.Fill(ds, "billall")
Dim doc1 As New ReportDocument
doc1.Load("D:\billing\DuraiRestaurent\CrystalReport2.rpt")
doc1.SetDataSource(ds)
CrystalReportViewer1.CrystalReport2.ReportSource = doc1
Cn.Close()
End Sub
End Class
When trying to execute an OleDBException error occurs: "No value given for one or more required parameters". Can you help?
When you receive this error it means that the Access Engine cannot correctly find one or more of your columns names or the whole table name.
To the OleDbDataAdapter I would say that you should use it like this (example):
String command = "SELECT movieId, name, headActor, Director, ReleaseDate, lenghtMin " &
"FROM Movies WHERE headactor = ?"
Dim adapter As OleDbDataAdapter = new OleDbDataAdapter(command, connectionString);
adapter.SelectCommand.Parameters.AddWithValue("#p1", lastName)
Someone help me
I am working on our project and I need to check if my DB has already 20 records.
If so, then it will not accept records anymore.
I've been trying the codes below:
Public Class Form1
Dim con As New OleDb.OleDbConnection
Dim ds, ds2 As New DataSet
Dim da, da2 As OleDb.OleDbDataAdapter
Dim sql, sql1 As String
Dim int As Integer
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
con.ConnectionString = "Provider=Microsoft.jet.OLEDB.4.0; data source = |datadirectory|\Database6.mdb"
con.Open()
Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand("SELECT * FROM Accounts WHERE Username='" & TextBox1.Text & "'", con)
Dim sdr As OleDb.OleDbDataReader = cmd.ExecuteReader
Dim cmd1 As OleDb.OleDbCommand = New OleDb.OleDbCommand("SELECT * FROM Accounts")
sql = "INSERT INTO Accounts ([Username], [Password], [FirstName], [LastName]) VALUES ('" & TextBox1.Text & "','" & TextBox2.Text & "', '" & TextBox3.Text & "','" & TextBox4.Text & "') "
sql1 = "SELECT Count([AccountID]) FROM Accounts"
cmd = New OleDb.OleDbCommand(sql, con)
cmd1 = New OleDb.OleDbCommand(sql1, con)
Convert.ToInt32(sql1)
cmd1.ExecuteScalar()
If sql1 < 20 Then
MsgBox("Cannot accept records")
ElseIf sdr.HasRows = False Then
cmd.ExecuteNonQuery()
MsgBox("Account Added")
ElseIf sdr.HasRows = True Then
MsgBox("Username is taken")
End If
con.Close()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Me.Hide()
Form2.Show()
End Sub
End Class
But the convert code fires an error :
Input string was in incorrect format
But if I delete the convert code it gives me the error
Conversion from string "SELECT Count([AccountID]) FROM A" to type 'Double' is not valid."
Help me please.
TIA
I dont know VB all that well, this is from the top of my head. Your trying to convert your SQL text, which will never work. Try something like this:
dim result as object
result = cmd1.ExecuteScalar()
dim count as int
count = Convert.ToInt32(result)
If count < 20 Then
I have just started learning VB.net for several weeks. i want to make a form and send data from a text box to a specific cell in ms access database (*.accdb) file. but the code i have writen gives the following error:
Syntax error in UPDATE statement.
i have checked several books and spent hours on internet, but no answer!
Dim con As New OleDb.OleDbConnection
Dim ds As New DataSet
Dim da As OleDb.OleDbDataAdapter
Dim sql As String
Dim cnn1 As New OleDb.OleDbConnection
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=
E:\Ebook\hararat\GUI\Heat Exchanger Designer\heat.accdb"
con.Open()
sql = "SELECT * FROM flow1"
da = New OleDbDataAdapter(sql, con)
da.Fill(ds, "flow1")
Dim cb As New OleDb.OleDbCommandBuilder(da)
ds.Tables("flow1").Rows(1).Item(1) = "name"
da.Update(ds, "flow1")
con.Close()
You need to use the .QuotePrefix and .QuoteSuffix properties of the OleDbCommandBuilder to wrap table and field names in square brackets. That is, instead of just
Dim cb As New OleDb.OleDbCommandBuilder(da)
you need to do
Dim cb As New OleDb.OleDbCommandBuilder(da)
cb.QuotePrefix = "["
cb.QuoteSuffix = "]"
That will generate an UPDATE statement of the form
UPDATE [TableName] SET [ColumnName]= ...
which is necessary if the table name or any of the field names happen to be reserved words in Access SQL.
Try this one
dim sqlupdate as string = "UPDATE tablename SET column_name = '" & textname.text & "' WHERE column_name = '" & textname.text & "'"
Sometimes errors occur when using the following column names: Username, Password, Date, Time, and much more of this type, try to avoid these column names because this might cause the problem of your issue regarding updating tables. Enable for you to update this kind of column name you need to enclose it with [ and ] so it comes like this: [Username], [Date], etc. so the syntax might go like this:
UPDATE tablename SET [Username] = '" & textname.text & "' WHERE column_name = '" & textname.text & "'"
my codes goes like this:
Open_Con()
Dim sqlUpdate As String
Dim sqlUpdatePass As DialogResult
sqlUpdate = "UPDATE tblAccounts SET [Password] = '" & txtRPassword.Text & "' WHERE [Username] = '" & txtUsername.Text & "'"
sqlCmd = New OleDbCommand(sqlUpdate, sqlCon)
Try
sqlUpdatePass = MessageBox.Show("Are you sure to save this changes?", "Save changes?", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
If sqlUpdatePass = vbYes Then
sqlCmd.ExecuteNonQuery()
MsgBox("Changes are now saved", MsgBoxStyle.Information, "New password has been set.")
Call ClearAll()
Me.Hide()
Else
Exit Sub
End If
Catch ex As Exception
MsgBox("Could not perform this task because " & ex.Message, MsgBoxStyle.Exclamation, "Error")
End Try
sqlCmd = Nothing
sqlCon.Close()
hope this things mention above codes helps your problem. have a nice day and happy coding :)
dim sqlupdate as string="UPDATE [tablename] SET [column_name] = '"& textname.text &"' WHERE [column_name] = '"& textname.text &"';"
By enclose attributes with square brackets, it appears to work I have tried it, it works
Imports System.Data.OleDb
Imports System.Data
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'Database2DataSet.identitas' table. You can move, or remove it, as needed.
Me.IdentitasTableAdapter.Fill(Me.Database2DataSet.identitas)
End Sub
Public Sub clean()
TextBox1.Clear()
TextBox2.Clear()
TextBox3.Clear()
TextBox4.Clear()
End Sub
Public Sub read()
Call openconn()
str = "select * from identitas"
dtadapter = New OleDbDataAdapter(str, con)
Dim dg As New DataTable
dg.Clear()
dtadapter.Fill(dg)
dgv.DataSource = dg
End Sub
Public Sub create()
Call openconn()
str = "insert into identitas values ('" & TextBox1.Text & "','" & TextBox2.Text & "','" & TextBox3.Text & "','" & TextBox4.Text & "') "
cmd = New OleDbCommand(str, con)
cmd.Connection = con
cmd.ExecuteNonQuery()
MsgBox("data lebet")
read()
clean()
End Sub
Public Sub update()
Call openconn()
str = "UPDATE identitas SET [Nama] = '" & TextBox2.Text & "',[Alamat] = '" & TextBox3.Text & "', [No] = '" & TextBox4.Text & "' where [NIK] = '" & TextBox1.Text & "'"
cmd = New OleDbCommand(str, con)
cmd.Connection = con
cmd.ExecuteNonQuery()
MsgBox("data ter ubah")
clean()
read()
End Sub
Public Sub delete()
Call openconn()
str = "delete from identitas where NIK = '" & TextBox1.Text & "'"
cmd = New OleDbCommand(str, con)
cmd.Connection = con
cmd.ExecuteNonQuery()
clean()
End Sub
Private Sub btnclose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnclose.Click
Me.Close()
End Sub
Private Sub btnc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnc.Click
create()
End Sub
Private Sub btnr_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnr.Click
read()
End Sub
Private Sub btnclean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnclean.Click
clean()
End Sub
Private Sub btnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnd.Click
Dim pesan As String = MsgBox("yakin mau hapus = " & TextBox1.Text & "?", MsgBoxStyle.YesNo)
If pesan = vbYes Then
delete()
End If
read()
End Sub
Private Sub btnu_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnu.Click
update()
End Sub
End Class
I had same problem, this helped.
"Sometimes errors occur when using the following column names: Username, Password, Date, Time, and much more of this type, try to avoid these column names because this might cause the problem of your issue regarding updating tables. Enable for you to update this kind of column name you need to enclose it with [ and ] so it comes like this: [Username], [Date], etc. so the syntax might go like this: "
I renamed the columns in Access (e.g Password1,Username1) as the same words password, username might be reserved in vb.net. Thanks for this response.
i am having some issues updating a table that i have in a VB.net Windows Forms in VS 2012
i have setup the database from a service Data base, it just need a small amount of data stored locally
what i am trying to do when i create a new user it update the data grid view
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
BDate1.Format = DateTimePickerFormat.Custom
BDate1.CustomFormat = "MM/dd/yyyy"
If fname.Text <> "" And lname.Text <> "" Then
If Not cn.State = ConnectionState.Open Then
cn.Open()
End If
' cn1.Open()
If rb1.Checked Then
gen = rb1.Text.ToString
ElseIf rb2.Checked Then
gen = rb2.Text.ToString
End If
cmd.CommandText = "INSERT INTO StudentTB (FirstName,LastName,Birthday,Avatar,Gender,Grade) values('" & fname.Text & "', '" & lname.Text & "', '" & BDate1.Text & "', '" & AvtarNM.Text & "', '" & gen & "', '" & TxtGrade.Text & "')"
Dim dt As New DataTable
dt.Load(cmd.ExecuteReader())
DataGridView1.DataSource = dt
' cmd.ExecuteNonQuery()
cn.Close()
fname.Text = ""
lname.Text = ""
the issue is that i can clear the table and reload it with button but it does not show the updated values with out closing the application then reopening it, i have tried a few thing and nothing seems to refresh the connection and or update the database. any help would help.
thanks
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
'DataGridView1.DataSource = Nothing
Database1DataSet1.StudentTB.Clear()
' Database1DataSet1.refresh()
' Dim myda As String
' cmd.Dispose()
' cmd.Connection = cn
'Me.Database1DataSet1.Clear()
Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
' 'myda = New SqlDataAdapter(cmd)
End Sub
here is the full code
Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlClient.SqlDataReader
Imports System.Windows.Forms
Public Class Student
Dim cn As New SqlConnection("Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Nate\documents\visual studio 2012\Projects\WindowsApplication9\WindowsApplication9\Database1.mdf;Integrated Security=True")
Dim cmd As New SqlCommand
Dim dr As SqlDataReader
Private dataAdapter As New SqlDataAdapter()
Dim gen As String
Dim bs As New BindingSource
Dim dt As New DataTable
Private Sub Student_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'Database1DataSet1.avTable' table. You can move, or remove it, as needed.
Me.AvTableTableAdapter.Fill(Me.Database1DataSet1.avTable)
'TODO: This line of code loads data into the 'Database1DataSet1.StudentTB' table. You can move, or remove it, as needed.
Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
cmd.Connection = cn
Form1.Hide()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If AvTableBindingSource.Position + 1 < AvTableBindingSource.Count Then
AvTableBindingSource.MoveNext()
Button7.PerformClick()
' Otherwise, move back to the first item.
Else
AvTableBindingSource.MoveFirst()
Button7.PerformClick()
End If
' Force the form to repaint.
Me.Invalidate()
End Sub
Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button7.Click
PictureBox1.Image = System.Drawing.Bitmap.FromFile(ID.Text)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
BDate1.Format = DateTimePickerFormat.Custom
BDate1.CustomFormat = "MM/dd/yyyy"
If fname.Text <> "" And lname.Text <> "" Then
If Not cn.State = ConnectionState.Open Then
cn.Open()
End If
' cn1.Open()
If rb1.Checked Then
gen = rb1.Text.ToString
ElseIf rb2.Checked Then
gen = rb2.Text.ToString
End If
cmd.CommandText = "INSERT INTO StudentTB (FirstName,LastName,Birthday,Avatar,Gender,Grade) values('" & fname.Text & "', '" & lname.Text & "', '" & BDate1.Text & "', '" & AvtarNM.Text & "', '" & gen & "', '" & TxtGrade.Text & "')"
cmd.ExecuteNonQuery()
dt.Load(cmd.ExecuteReader())
bs.DataSource = dt
DataGridView1.DataSource = bs
cn.Close()
fname.Text = ""
lname.Text = ""
End If
End Sub
Private Sub genPCI()
If rb1.Checked Then
gen = rb1.Text.ToString
ElseIf rb2.Checked Then
gen = rb2.Text.ToString
End If
End Sub
Public Function ChangeFormat(ByVal dtm As DateTime, ByVal format As String) As String
Return dtm.ToString(format)
End Function
Private Sub Closestudent_Click(sender As Object, e As EventArgs) Handles Closestudent.Click
Form1.Show()
Me.Close()
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
bs.EndEdit()
dataAdapter.Update(dt)
DataGridView1.DataSource = dt
' dt.Load(Command.ExecuteReader())
'Database1DataSet1.Reset()
'DataGridView1.Columns.Clear()
' DataGridView1.DataSource = Nothing
' Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
' StudentTBBindingSource.ResetBindings(True)
' Database1DataSet1.refresh()
' Dim myda As String
' cmd.Dispose()
' cmd.Connection = cn
' StudentTBBindingSource.ResetBindings(False)
'Database1DataSet1.StudentTB.Clear()
' 'myda = New SqlDataAdapter(cmd)
' DataGridView1.DataSource = Database1DataSet1.StudentTB
End Sub
End Class
You can try like this
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
bs.EndEdit()
dataadapter.Update(dt)
DataGridView1.DataSource = dt
End Sub
UPDATE
or you can use bindingdatasource and delare it on your form class
Dim bs As New BindingSource
and in datagridview .. in button1_click
Dim dt As New DataTable
dt.Load(cmd.ExecuteReader())
bs.DataSource = dt
DataGridView1.DataSource = bs
So, if updated then will show after button4_click
Datagridview1.datasource = nothing
Dataset.reset
dim cmd as new sqldataadapter
cmd = "SELECT * FROM YOUR_DATABSE", con
con.open
cmd.fill(Dataset)
datagridview1.datasource = dataset(0).defaultview
Add these code to you button insert
okay after a lot of playing around this seem to fix my issue http://msdn.microsoft.com/en-us/library/fbk67b6z.aspx well all i can say it is working no idea why but it works.
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
Me.DataGridView1.DataSource = Me.StudentTBBindingSource
GetData("select * from StudentTB")
End Sub
Private Sub GetData(ByVal selectCommand As String)
Try
' Specify a connection string. Replace the given value with a
' valid connection string for a Northwind SQL Server sample
' database accessible to your system.
Dim connectionString As String = "Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Nate\documents\visual studio 2012\Projects\WindowsApplication9\WindowsApplication9\Database1.mdf;Integrated Security=True"
' Create a new data adapter based on the specified query.
Me.dataAdapter = New SqlDataAdapter(selectCommand, connectionString)
' Create a command builder to generate SQL update, insert, and
' delete commands based on selectCommand. These are used to
' update the database.
Dim commandBuilder As New SqlCommandBuilder(Me.dataAdapter)
' Populate a new data table and bind it to the BindingSource.
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.dataAdapter.Fill(table)
Me.StudentTBBindingSource.DataSource = table
' Resize the DataGridView columns to fit the newly loaded content.
' Me.DataGridView1.AutoResizeColumns( _
' DataGridViewAutoSizeColumnsMode.AllCellsExceptHeader)
Catch ex As SqlException
MessageBox.Show("To run this example, replace the value of the " + _
"connectionString variable with a connection string that is " + _
"valid for your system.")
End Try
End Sub
By Using ComboBox To Search
sql = " select * from english_language where lang=' " & ComboBox2.Text & " ' "
da = New OleDb.OleDbDataAdapter(sql, con)
Dim dt As New DataTable
da.Fill(dt)
DataGridView1.DataSource = dt
DataGridView1.Refresh()
Try this code to btnClear.
DataGridView.DataSource = 0
Press clear button. After that click the reload button that you coded.
I think it will reset and reload the data in data grid view.