So I have been able to connect my database to VB forms, and I am also able to see the table and the fields within. But I can't figure how to make the data appear in the table because it's just blank.
I do have some data stores in the actual access database but it won't show up in my program.
Is there a particular code I need to write? This is what I have so far. The database is called the 'POS system'.
Private Sub OrdersBindingNavigatorSaveItem_Click(sender As Object, e As EventArgs) Handles OrdersBindingNavigatorSaveItem.Click
Me.Validate()
Me.OrdersBindingSource.EndEdit()
Me.TableAdapterManager.UpdateAll(Me.POS_systemDataSet)
End Sub
It is usually a good idea to separate your database code from your user interface code. Create a connection and a command in a Using block so they will be closed and disposed at End Using. Pass the connection string to the constructor of the connection. Pass the CommandText and connection to the constructor of the command. Open the connection and execute the command returning a DataReader to load the DataTable.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = GetData()
DataGridView1.DataSource = dt
End Sub
Private Function GetData() As DataTable
Dim dt As New DataTable
Using cn As New OleDbConnection("Your connection string"),
cmd As New OleDbCommand("Select * From SomeTable;", cn)
cn.Open()
Using reader = cmd.ExecuteReader
dt.Load(reader)
End Using
End Using
Return dt
End Function
Related
When I enter the fields it works and sends the records to the database and if I clear the form and enter another it also sends that one to the database but when I stop debugging, the database is empty.
Is there something wrong with my code?
What should I do to resolve this issue?
• I am using VB.NET with a Microsoft Access database
• There are two pages of code: Control and Create Account Form
Control
Imports System.Data.OleDb
Public Class DBControl
'CREATE YOUR DB CONNECTION
Private DBCon As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;" &
"Data Source=Hotel.mdb;")
'PREPARE DB COMMAND
Private DBCmd As OleDbCommand
'DB DATA
Public DBDA As OleDbDataAdapter
Public DBDT As DataTable
'QUERY PARAMETERS
Public Params As New List(Of OleDbParameter)
'QUERY STATISTICS
Public RecordCount As Integer
Public Exception As String
Public Sub ExecQuery(Query As String)
'RESET QUERY STATS
RecordCount = 0
Exception = ""
Try
'OPEN A CONNECTION
DBCon.Open()
'CREATE DB COMMAND
DBCmd = New OleDbCommand(Query, DBCon)
'LOAD PARAMS INTO DB COMMAND
Params.ForEach(Sub(p) DBCmd.Parameters.Add(p))
'CLEAR PARAMS LIST
Params.Clear()
'EXECUTE COMMAND & FILL DATABASE
DBDT = New DataTable
DBDA = New OleDbDataAdapter(DBCmd)
RecordCount = DBDA.Fill(DBDT)
Catch ex As Exception
Exception = ex.Message
End Try
'CLOSE YOUR CONNECTION
If DBCon.State = ConnectionState.Open Then DBCon.Close()
End Sub
'INCLUDE QUERY & COMMAND PARAMETERS
Public Sub AddParam(Name As String, Value As Object)
Dim NewParam As New OleDbParameter(Name, Value)
Params.Add(NewParam)
End Sub
End Class
Create Account Form
Imports System.Data.OleDb
Public Class Create
Private Access As New DBControl
Private DBCon As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;" &
"Data Source=Hotel.mdb")
Private Sub Create_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If DBCon.State = ConnectionState.Closed Then DBCon.Open() : Exit Sub
End Sub
Private Sub btnCreate_Click(sender As Object, e As EventArgs) Handles btnCreate.Click
AddUser()
End Sub
Private Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.Click
txtForename.Clear()
txtSurname.Clear()
txtNumber.Clear()
txtEmail.Clear()
txtPass.Clear()
txtCity.Clear()
End Sub
Private Sub cbxTitle_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbxTitle.SelectedIndexChanged, txtFirst.TextChanged, txtSurname.TextChanged, txtEmail.TextChanged, txtPass.TextChanged
If Not String.IsNullOrWhiteSpace(cbxTitle.Text) AndAlso Not String.IsNullOrWhiteSpace(txtFirst.Text) AndAlso Not String.IsNullOrWhiteSpace(txtSurname.Text) AndAlso Not String.IsNullOrWhiteSpace(txtEmail.Text) AndAlso txtPass.Text.Length = 8 Then
btnCreate.Enabled = True
End If
End Sub
Private Sub AddUser()
'ADD PARAMETERS
Access.AddParam("#Title", cbxTitle.Text)
Access.AddParam("#Forename", txtForename.Text)
Access.AddParam("#Surname", txtSurname.Text)
Access.AddParam("#Number", txtNumber.Text)
Access.AddParam("#Email", txtEmail.Text)
Access.AddParam("#Pass", txtPass.Text)
Access.AddParam("#City", txtCity.Text)
'EXECUTE INSERT COMMAND
Access.ExecQuery("INSERT INTO Customers([Title], [Forename], [Surname], [Number], [Email], [Pass], [City])" &
"VALUES(#Title, #Forename, #Surname, #Number, #Email, #Pass, #City)")
'REPORT & ABORT ON ERRORS
If Not String.IsNullOrEmpty(Access.Exception) Then MsgBox(Access.Exception) : Exit Sub
DBCon.Close()
End Sub
End Class
Any help is appreciated
Thank you in advance :)
There is a proper way to work with file-based databases in VB.NET.
Add the data file to your project in the Solution Explorer. If you're prompted to copy the file into the project, accept.
Set the Copy To Output Directory property of the data file to Copy If Newer.
Use "|DataDirectory|" to represent the folder path of the data file in your connection string, e.g. Dim connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Hotel.mdb;".
Now you have two copies of your database. You have the one in the project folder, with the other source files, and the one in the output folder, with the EXE. The source file should stay clean, unsullied by test data. The copy in the output folder is the one you connect to when you debug so that's the one you need to look in to find any changes you make while debugging/testing.
Because you set it to only copy when the source file is newer than the output file, any changes you make while testing will not be lost unless you actually make a change to the source file, e.g. add a column or a table. By default, that property is set to Copy Always, which means that your source file is copied over the output file every time the project is built, so any time any source file changes and you run the project again. That's why your data "disappears".
I want to load or show the data from SQL Server on a DataGridView.
The build succeeds and there's no error when I run it. There's nothing wrong in form modul_koneksi (I think) because it works on my other form (form_login)
However, nothing shows up in my DataGridView. How can I fix this?
Code:
Imports System.Data.SqlClient
Public Class FormProduk
Private Sub FormProduk_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
Dim str As String = "Data Source=Fahriy;Initial Catalog=DBLogin;Integrated Security=True"
Dim connection As New SqlConnection(str)
Dim com As String = "Select * From tbl_user"
Dim dataadapter As New SqlDataAdapter(com, connection)
Dim dataset As New DataSet()
dataadapter.Fill(dataset, "tbl_user")
DataGridView1.DataSource = dataset.Tables()
End Sub
End Class
You should define which table to load in the DataGridView:
DataGridView1.DataSource = dataset.Tables("tbl_user")
You cannot set the .DataSource property with dataset.Tables. Instead you need to set it with a DataTable located in your DataSet:
DataGridView1.DataSource = dataset.Tables("tbl_user")
However I think you could simplify the code a little by getting rid of the SqlDataAdapter and loading straight into a DataTable
Dim dt As New DataTable
dt.Load(com.ExecuteReader())
DataGridView1.DataSource = dt
I would also consider implementing Using:
Sometimes your code requires an unmanaged resource, such as a file handle, a COM wrapper, or a SQL connection. A Using block guarantees the disposal of one or more such resources when your code is finished with them. This makes them available for other code to use.
With the changes your code would look something like this:
Dim dt As New DataTable
Using con As New SqlConnection("Data Source=Fahriy;Initial Catalog=DBLogin;Integrated Security=True"),
cmd As New SqlCommand("SELECT * FROM tbl_user", con)
con.Open()
dt.Load(cmd.ExecuteReader())
End Using
DataGridView1.DataSource = dt
Not enough info to tell, are you sure your connection string str is correct. You can try change to this code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim str As String = "Data Source=Fahriy;Initial Catalog=DBLogin;Integrated Security=True"
Dim conn As New SqlConnection(str)
Dim cmd As String = "Select * From tbl_user"
Dim adapter As New SqlDataAdapter(cmd, conn)
Dim tabeluser As New DataSet
adapter.Fill(tabeluser)
DataGridView1.DataSource = tabeluser.Tables
End Sub
I have a conundrum.
In my VB.net program, in multiple places I communicate with my SQLserver database. I use Insert, Update and Select statements. My program is made up of multiple forms and my database has 4 tables.
All but one of my subs is working, and despite using break-points and walk through's of the code I can not figure out why.
The form and database tables in question are fine with the select and Insert statements are fully functioning, however the code of the update statement is not. When I run a walk through it behaves as if it has sent the data to the database, however the database never receives it. The connection data is identical to the functioning subs, and the code is in the same format as my update code in other forms within my program. So I can't see why its not working.
Here is the code:
Public selectedDeviceNumber As String = ""
Public selectedDeviceRowNumber As Integer = 0
'================================
'= Set up the DATASETS! =
'================================
Dim PCBconnectionstring As String = "Data Source=ServerName;Initial Catalog=Databasename;User Id=UserId;Password=password;Connect Timeout=30;User INstance=False"
Dim PCBsqlconnection As New SqlClient.SqlConnection(PCBconnectionstring)
Dim damyPCB As New SqlDataAdapter
Dim dsmyPCB As New DataSet
Dim ALcon As New SqlConnection
Dim ALcmd As New SqlCommand
Dim PCBcmd As New SqlCommand
Dim PCBcon As New SqlConnection
'================================
'= SAVE the data! =
'================================
Dim test As String = Me.selectedDeviceNumber
Private Sub SaveToDataBaseFunctionPCB()
'update the data entered to the database
Try
PCBsqlconnection.ConnectionString = "Data Source=ITWIN10-PC\SQL2010;Initial Catalog=SLE1000;User Id=UserId;Password=password;Connect Timeout=30;User Instance=False"
PCBsqlconnection.Open()
PCBcmd.Connection = PCBsqlconnection
PCBcmd.CommandText = "UPDATE PCBlist SET pcbSerial=#pcbSerial,pcbPart=#pcbPart,pcbVent=#pcbVent,pcbDesc=#pcbDesc," & _
"pcbTested=#pcbTested,pcbU1=#pcbU1,pcbU5=#pcbU5,pcbU7=#pcbU7,pcbU10=#pcbU10,pcbU11=#pcbU11,pcbVersion=#pcbVersion," & _
"pcbTestIni=#pcbTestIni,pcbApplyIni=#pcbApplyIni,pcbTestDate=#pcbTestDate,pcbApplyDate=#pcbApplyDate WHERE pcbID=#pcbID "
PCBcmd.Parameters.AddWithValue("#pcbSerial", txtSerialPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbPart", cboPartPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbVent", txtVentPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbDesc", txtDescriptPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbTested", chkTested1.Checked)
PCBcmd.Parameters.AddWithValue("#pcbU1", txtU11.Text)
PCBcmd.Parameters.AddWithValue("#pcbU5", txtU51.Text)
PCBcmd.Parameters.AddWithValue("#pcbU7", txtU71.Text)
PCBcmd.Parameters.AddWithValue("#pcbU10", txtU101.Text)
PCBcmd.Parameters.AddWithValue("#pcbU11", txtU111.Text)
PCBcmd.Parameters.AddWithValue("#pcbVersion", txtVersionPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbTestIni", txtTestPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbApplyIni", txtApplyPCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbTestDate", txtTestDatePCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbApplyDate", txtApplyDatePCB1.Text)
PCBcmd.Parameters.AddWithValue("#pcbID", Me.selectedDeviceNumber)
PCBcmd.ExecuteNonQuery()
PCBcmd.Parameters.Clear()
PCBsqlconnection.Close()
MsgBox("Data updated")
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
PCBsqlconnection.Close()
End Try
End Sub
`Private Sub btnAmend_Click(sender As System.Object, e As System.EventArgs) Handles btnAmend.Click
'Save the data to SQL Server
SaveToDataBaseFunctionPCB()
'record activity in Activity Log
FrmSLE1000.txtActivityLogRecorder.Text = ("Data Saved")
'Save the Activity log data to SQL Server
SaveToDataBaseFunction1()
'SLE1000SqlConnection = New SqlConnection(frmConnections.lblDBConnection.Text & frmConnections.lblDBConnection2.Text)
End Sub
If you have any ideas then please let me know. It could be that I've been looking at the code too long and its obvious, however I can't see the problem.
Many thanks
After extensive fiddling with my code I have fixed the problem. As it turns out the problem lay further back in the code. When the Select statement was called it loaded the data into a list view, which you then select a row which you want to edit. The catch ex as exception was being fired at this point, however the data was still being passed to the text boxes so that you could edit the data, so I mentally 'parked' that glitch for later. In solving that glitch the "amend" button and Update function works fine.
If you're interested the original glitch in the code was as follows
Private Sub lvPCB1_DoubleClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lvPCB1.DoubleClick
Dim newmachine As String = FrmSLE1000.txtNo.Text
Try
If lvPCB1.SelectedItems.Count = 0 Then
MessageBox.Show("Ensure that you have selected a PCB Board. Try again.")
Exit Sub
Else
'Set selected units ID number in varable to allow access to all row data to populate tables
selectedDeviceNumber = lvPCB1.SelectedItems(0).Text
PopulateTablesFunctionPCB()
txtSerialPCB1.Text = lvPCB1.SelectedItems(1).Text
'record activity in Activity Log
End If
Catch ex As Exception
MessageBox.Show("Problem with selection")
End Try
End Sub
and the new working code is as follows
Private Sub lvPCB1_DoubleClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lvPCB1.DoubleClick
Dim newmachine As String = FrmSLE1000.txtNo.Text
Try
If lvPCB1.SelectedItems.Count = 0 Then
MessageBox.Show("Ensure that you have selected a PCB Board. Try again.")
Exit Sub
Else
'Set selected units ID number in varable to allow access to all row data to populate tables
selectedDeviceNumber = lvPCB1.SelectedItems(0).Text
PopulateTablesFunctionPCB()
txtSerialPCB1.Text = lvPCB1.SelectedItems(0).Text
'record activity in Activity Log
End If
Catch ex As Exception
MessageBox.Show("Problem with selection")
End Try
End Sub
So it all came down to having a "1" instead of a "0" in the line "txtSerialPCB1.Text = lvPCB1.SelectedItems(0).Text"
And there you have it!
I am very new to VB 2015. I want to learn about database update command. I try to understand SqlDataAdapter. Could anyone please advise me? As my code below, it run completely with no error, but my database table (WORKSHEET) was not updated.
Imports System.Data.SqlClient
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim command2 As String
command2 = "Update WORKSHEET set cancel_flag = 'Y' WHERE CNumber LIKE #reversalNumber"
Using con2 As New SqlConnection(WindowsApplication1.My.Settings.SaleCommDatabaseConnectionString)
Using cmd2 As New SqlCommand(command2)
Using oda2 As New SqlDataAdapter
cmd2.Connection = con2
con2.Open()
cmd2.Parameters.Add("#reversalNumber", SqlDbType.VarChar, 10, "15332")
oda2.UpdateCommand = New SqlCommand(command2, con2)
End Using
End Using
End Using
MsgBox("ggggg")
End Sub
End Class
The SqlDataAdapter class is useful for applying changes from a DataSet to the database. Try filling a DataSet with the modified data, and then apply changes using the adapter's update method (oda2.Update(WORKSHEET)).
EDIT: Make sure that you fill the DataSet with the data by using the SqlDataAdapter's Fill method.
oda2.Fill(yourDataSet)
Before this, you need to select the proper command with oda2.SelectCommand = YourCommand.
I am facing a problem displaying the records of my table on the visual basic form I have created.
This is my code :
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
myconnection = New SqlConnection("server=HOME-PC\SQLEXPRESS;uid=sa;pwd=123;database=college")
myconnection.Open()
mycommand = New SqlCommand("SELECT * from demo3)", myconnection)
Dim mySqlDataAdapter As New SqlDataAdapter(mycommand)
Dim mydsStudent As New DataSet()
mySqlDataAdapter.Fill(mydsStudent, "Student")
ra = mycommand.ExecuteNonQuery()
MessageBox.Show("Data Displayed" & ra)
myconnection.Close()
End Sub
End Class
Note: my database name is "college" , table name is "demo3" . Table contains 2 columns namely name and roll no. How to display the data in those columns on the visual basic form that I have created ?
You don't need to call execute non query. You can bind the dataset to a DataGridView. Like this
Dim DataGridView1 as new DataGridView()
DataGridView1.DataSource = mydsStudent
'Your table goes here, not sure about the exact propety name, hope it works.
DataGridView1.DisplayMember = "demo3"
Me.Controls.Add(DataGridView1)