I want to fill a DataGridView with data returned from a SQL. So here is my code [I provided cause some people may think I'm asking for help before trying myself]
I want the DataGridView to be filled by a data from SQL not to show all the records.
The SQL "Select * From books where title='php%' Order By Title;"
useless code :( :'( :<
Imports System.Data
Imports System.Data.SqlClient
Public Class frmMain
Dim connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Database.mdb;Persist" & " Security Info=True"
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.BooksTableAdapter.Fill(Me.TblBooks.books)
End Sub
Private Sub txtTerm_TextChanged() Handles txtTerm.TextChanged
If Trim(txtTerm.Text) = "" Then Exit Sub
Dim tblCustomBooks As New DataTable
Dim adpBooks As New OleDb.OleDbDataAdapter("Select * From books where title='php%' Order By Title", _
'"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Database.mdb;Persist" & " Security Info=True")
adpBooks.Fill(tblCustomBooks)
BooksTableAdapter.Fill(tblCustomBooks)
'Dim myConnection As SqlConnection
'Dim myCommand As SqlDataAdapter
'myConnection = New SqlConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Database.mdb;Persist" & " Security Info=True")
'myCommand = New SqlDataAdapter("Select * From books where title='php%' Order By Title", myConnection)
'Dim ds As DataSet = New DataSet()
'myCommand.Fill(ds)
'gridTable.DataSource = ds
End Sub
Looks like you've tried a number of different things, but it's not apparent from your code what order you tried them in. Based on the current version of your code, you're missing two things:
First, an OleDBConnection object to use with the OleDbDataAdapter.
Second, you're not assigning anything to the DataGridViews DataSource property, so nothing will show up.
Also, you appear to be using two different OleDbDataAdapters (or maybe two different DataAdapters altogether) to fill tblCustomBooks, so depending on what BooksTableAdapter is set up as may also be causing you problems.
Try this:
Private Sub txtTerm_TextChanged() Handles txtTerm.Changed
If Trim(txtTerm.Text) = "" Then Exit Sub
Dim tblCustomBooks As New DataTable
Using conn As New OleDbConnection(connectionString)
Dim adpBooks As New OleDbDataAdapter("SELECT * FROM books WHERE title = 'php%' ORDER BY title", conn)
adpBooks.Fill(tblCustomBooks)
gridTable.DataSource = tblCustomBooks
End Using
End Sub
See:
DataGridView.DataSource Property
OleDbDataAdapter Class
In your SQL statement try [WHERE Title LIKE 'php%'] instead of [WHERE Title = 'php%'].
I've run into similar problems with MS SQL and this was the fix. I'm not sure if the SQL syntax is the same for the Jet provider, but it's worth a try at least.
HTH
dim dt as new datatable
'i already maked the class and now load from a database
dt=cls.getdata("select * from tblinf")
datagridview1.datasource=dt
Related
I have written a generic VB.net subroutine that populates a datagrid with the results of a query. The subroutine as one parameter, strQuery, which is a string that can translate to any valid SQL-Server view or stored procedure that returns a recordset. Other than that, there is no constraint on the SQL code, and sending two queries that have entirely different field profiles is a valid proposition.
In order to get this to work, I must completely purge the data grid of whatever dataset had been there previously, thus allowing the control to drop its prior identity and start over, allowing, from scratch, the new dateset to redefine the control's contents.
I have finally solved the problem. Perhaps I should have mentioned that I am using Visual Studio 2010, and that if Hersey were using a later version, then the code that worked for him may not have worked for me. The change to my code is one additional line: setting both the name and datapropertyname to the same name. I noticed that when I went to look at the column view, I noticed that the datapropertyname is how the table links to the source, and the name is an effective alias for the field, how it will be presented. Obviously, for clarity sake, both must be the same! This now works as advertised.
Thanks, ~ Peter Ferber
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim con As New SqlConnection("<Enter Connection string here>")
Dim rcd As ADODB.Recordset = ReturnRecordset("Select * From ExcludeWords")
Call DefineDataGrid("Select * From ExcludeWords")
End Sub
Private Sub btnUpdate_Click(sender As System.Object, e As System.EventArgs) Handles btnUpdate.Click
Call DefineDataGrid("Select * From FindWords")
End Sub
Sub DefineDataGrid(ByVal strQuery As String)
Dim con As New SqlConnection("<Enter Connection String Here>")
Dim dt As New DataTable
FindWordGrid.Columns.Clear()
FindWordGrid.DataSource = Nothing
Dim rcd As ADODB.Recordset = ReturnRecordset(strQuery)
Dim MyField As ADODB.Field
Dim iCount As Integer = -1
FindWordGrid.ColumnCount = rcd.Fields.Count
For Each MyField In rcd.Fields
iCount = iCount + 1
FindWordGrid.Columns(iCount).Name = MyField.Name
FindWordGrid.Columns(iCount).DataPropertyName = MyField.Name
Next
Dim cmd As New SqlCommand(strQuery, con)
Dim da = New SqlDataAdapter(cmd)
da.Fill(dt)
FindWordGrid.DataSource = dt
End Sub
Function ReturnRecordset(strQuery As String) As ADODB.Recordset
Dim con As ADODB.Connection = "<Enter Connection string here>"
ReturnRecordset = New ADODB.Recordset
ReturnRecordset.Open(strQuery, con)
End Function
My setup is easy to reproduce: I am using datasets with only a handful of records in each respective table. The only constraint is that the respective runs must have a different field profile. I have been experimenting with different techniques for much of the day, and I now think it best to get some new grey matter on the subject. Getting this process correctly is the last major hurdle for me, in making a key presentation I wish to make, in lobbying for a job role. Thanks, in advance, for your comments, thoughts, and ideas.
Sincerely, ~ Peter Ferber
So, made a couple modifications to the DefineDataGrid code you've posted. Seems to be working for me. I suspect might be something to do with the life cycle of either your cmd or con objects causing your problem. Parsing a number of different number of queries through to it and it rebuilds the datagridview correctly
Sub DefineDataGrid(ByVal strQuery As String)
Dim dt As New DataTable
FindWordGrid.DataSource = Nothing
Using con As New SqlConnection("Your Connection String Here")
Using cmd As New SqlCommand(strQuery, con)
Dim da = New SqlDataAdapter(cmd)
da.Fill(dt)
FindWordGrid.DataSource = dt
End Using
End Using
End Sub
Changed the obvious module level implementations of con and cmd to local variables, and since both types implement IDisposable, wrapped them in a Using pattern
Private Function CreatePlayerAdapter(ByVal playerDBconnection As OleDbConnection) As OleDbDataAdapter
// Initiating instances for the function
Dim dataAdapter As OleDbDataAdapter = New OleDbDataAdapter()
Dim myCommand As OleDbCommand
Dim parameter As OleDbParameter
// establishing the string to tell where to delete record from and how to find the record i want.
// PlayerIDTextBox.Text is a text on a form that is populated from the database after selecting a list of name (this works correctly) // connection is already open and is directed to correct place
Dim sql As String = "DELETE * FROM Players WHERE ID ='" & CInt(PlayerIDTextBox.Text) & "'"
myCommand = New OleDbCommand(sql, playerDBconnection)
parameter = myCommand.Parameters.Add("ID", OleDbType.Char, 3, "ID")
parameter.SourceVersion = DataRowVersion.Original
dataAdapter.DeleteCommand = myCommand
Return dataAdapter
End Function
// i call this function after executing a button click.
//ListPlayerComboBox.Text is populated with the names and needs it a name to fill PlayerIDTextBox.Text(works correctly)
Private Sub RemovePlayerButton_Click(sender As System.Object, e As System.EventArgs) Handles RemovePlayerButton.Click
If ListPlayerComboBox.Text = " " Then
MsgBox("Please Select a Player.")
Else
Me.CreatePlayerAdapter(playerDBConnection)
End If
End Sub
// no errors occur. However, nothing is done in the database. help please?
Notes:
1)Never leave your OleDbConnection Open. Only allow it to be opened when you actually need it. This will save you from a lot of headaches later on. The reasons why can be found on following stackoverflow question.
2) There is no reason to return an OleDbDataAdapter if you don't intend on using it.
3) Use your parameters correctly : see below example2
4) Keep in mind that there are some restricted keywords in Access. Luckely for you ID isn't one. The restrictedKeywords can be found here: Keywords
I'm probably missing some further points here. Anyone should be free to add em.
Why not adjust your Function CreatePlayerAdapter to the following:
1) Without parameters
Private Sub CreatePlayerAdapter(ByVal playerDBconnection As OleDbConnection)
Dim myCommand As OleDbCommand
Dim sql As String = "DELETE * FROM Players WHERE ID =" & CInt(PlayerIDTextBox.Text)
myCommand = New OleDbCommand(sql, playerDBconnection)
playerDBconnection.Open()
myCommand.ExecuteNonQuery()
playerDBconnection.Close()
End Sub
2) With parameters
Private Sub CreatePlayerAdapter(ByVal playerDBconnection As OleDbConnection)
Dim myCommand As OleDbCommand
Dim sql As String = "DELETE * FROM Players WHERE ID = #playerId"
myCommand = New OleDbCommand(sql, playerDBconnection)
Dim param As New OleDb.OleDbParameter(#playerId", CInt(PlayerIDTextBox.Text))
myCommand.Add(param)
playerDBconnection.Open()
myCommand.ExecuteNonQuery()
playerDBconnection.Close()
End Sub
The method ExecuteNonQuery executes the query passed to the command on the specified OleDbConnection and returns the number of rows affected. More info Here
This is my first post in here, but this forum already helped me a lot.
First, sorry for my English, i'm from Brazil and i'm trying to write without a translator.
I'm developing a software for a supermarket, but i'm having problems with the connection to the database. I'm trying to make all the connections and transactions programmatically (DataSets, BindingSources and so).
I've already managed to connect with SQL Server Express 2008, using a Function ("consulta") inside a Module ("db"):
Dim ad As SqlDataAdapter = New SqlDataAdapter
Function consulta(ByVal tabela As String, Optional opt As Boolean = False, Optional optparam As String = "") As DataSet
Dim ds As New DataSet
Try
Dim connstring As String = "Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=SysMarket;Persist Security Info=True;User ID=admin;Password=XXXXXX"
Dim conObj As New SqlConnection(connstring)
Dim sql As String
If opt = True Then
sql = "SELECT * FROM " & tabela & " " & optparam
Else
sql = "SELECT * FROM " & tabela
End If
Dim cmd As SqlCommand = New SqlCommand(sql, conObj)
ad.SelectCommand = cmd
conObj.Open()
ad.Fill(ds, tabela)
ad.Dispose()
cmd.Dispose()
conObj.Close()
Return ds
Catch ex As Exception
MessageBox.Show("Erro na consulta" & vbCrLf & ex.InnerException.ToString, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error)
ds.Clear()
Return ds
End Try
End Function
And this is a part of the main code where I make a SelectQuery and put into a BindingSource:
Dim ds As DataSet = db.consulta("departamentos")
Private Sub cad_departamento_Load(sender As Object, e As EventArgs) Handles MyBase.Load
BindingSource1.DataSource = ds
BindingSource1.DataMember = "departamentos"
TextBox1.DataBindings.Add("Text", BindingSource1, "id")
TextBox2.DataBindings.Add("Text", BindingSource1, "departamento")
End Sub
But my problem is when I have to Update the database, by adding, editing or deleting some item from BindingSource. Because in the Module I've closed the connection to the SQL Server. So I will need reopen this connection and then, somehow "read" the DataSet with the change and Update the database?
Someone could explain this to me or show me a example?
Thank you.
You will use a data adapter to save the data, just as you used one to retrieve the data. You will have to create an InsertCommand if you want to insert new records, an UpdateCommand if you want to update existing records and a DeleteCommand if you want to delete existing records. You can write those yourself or, if the conditions are right, you can use a command builder to do it for you.
If your query is based on a single table and you want to insert/update all the columns you retrieve back to that same table then a SqlCommandBuilder may be your best bet. You simply pass in the query and the command builder will use it to generate the action commands. That gives you limited flexibility but if you're just doing single-table operations then you don't need that added flexibility.
Such a method might look something like this:
Public Sub SaveChanges(tableName As String, data As DataSet)
Dim query = "SELECT * FROM " & tableName
Using adapter As New SqlDataAdapter(query, "connection string here")
Dim builder As New SqlCommandBuilder(adapter)
adapter.Update(data, tableName)
End Using
End Sub
I did what you said, but when I open the Form again, the new data are not there.
I made some changes in the code, perhaps because it did not work
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
BindingSource1.EndEdit()
ds.AcceptChanges()
db.SaveChanges("departamentos", "INSERT INTO departamentos VALUES('', " & TextBox2.Text & ")", ds)
ds = db.consulta("departamentos")
End Sub
And the code in the Module
Function SaveChanges(tableName As String, query As String, data As DataSet)
Using adapter As New SqlDataAdapter(query, "Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=SysMarket;Persist Security Info=True;User ID=admin;Password=XXXXX")
Dim builder As New SqlCommandBuilder(adapter)
adapter.Update(data, tableName)
Return True
End Using
End Function
Dim myconn As New SqlConnection("Server=server,Trusted_Connection=True,Database=database")
'selects from mt table linking the current pc to a row
Dim sql As String = "SELECT * from idset " & vbcrlf &
"Where pcname= '" & pcname & "'"
Dim ds As New DataSet
Dim da As New SqlDataAdapter(sql, myconn)
da.Fill(ds, "Setup")
txtClientID.DataBindings.Add("text", ds.Tables("idset"), "CLID")
I don't know why its not working for some reason its not filling the data set did I declare something wrong?
The reason why it don't work is because you specify that the incoming table should be mapped to a table named Setup. Your data set doesn't contain a table named Setup, so the incoming table will be named... well, Setup.
Try this instead:
da.Fill(ds, "idset")
Also, I strongly suggest you:
Set option strict on
Always use parameterized/prepared SQL queries.
Always use the Using statement when working with disposable objects.
Seriously.
The best way to debug bindings is to use a BindingSource and handle the BindingComplete event.
Private bs As BindingSource
Private ds As DataSet
Private Sub Initialize(pcname As String)
Me.ds = New DataSet()
Using connection As New SqlConnection("Server=server,Trusted_Connection=True,Database=database")
connection.Open()
Using command As New SqlCommand()
command.Connection = connection
command.CommandText = "SELECT * from [idset] Where [pcname] = #pcname;"
command.Parameters.AddWithValue("#pcname", pcname)
Using adapter As New SqlDataAdapter(command)
adapter.Fill(Me.ds, "idset")
End Using
End Using
End Using
Me.bs = New BindingSource(Me.ds, "idset")
AddHandler bs.BindingComplete, AddressOf Me.HandleBindingCompleted
Me.txtClientID.DataBindings.Add("Text", Me.bs, "CLID")
End Sub
Private Sub HandleBindingCompleted(sender As Object, e As BindingCompleteEventArgs)
If (Not e.Exception Is Nothing) Then
Debug.WriteLine(e.ErrorText)
End If
End Sub
I was developing an application using oop concept.I have a class that has 2 attributes and have Get and Set methods namely WorkItemNumber and Description.
On the client side i have a list box used to populate the work items based on their description.Here's the code i wrote in the class o read items from the database.
Public Sub LoadWorkItem()
' Load the data.
' Select records.
Dim oWorkItem As WorkItem = New WorkItem()
Dim conn As New OleDbConnection
Dim data_reader As OleDbDataReader
conn = oWorkItem.GetDbConnection()
Dim cmd As New OleDbCommand("SELECT * FROM work_item ORDER BY [work item number]", conn)
data_reader = cmd.ExecuteReader()
'ListBox1.Items.Clear()
If data_reader.HasRows = True Then
Do While data_reader.Read()
WorkItemNumber = data_reader.Item("work item number")
Description = data_reader.Item("description")
Loop
End If
data_reader.Close()
data_reader = Nothing
cmd.Dispose()
cmd = Nothing
conn.Close()
conn.Dispose()
End Sub
How do i populate the listbox using the code,and if there's any improvement on the code please do tell me as well.Thank you
To poulate your ListBox, do this...
ListBox1.Item.Clear()
If data_reader.HasRows Then
Do While data_reader.Read()
WorkItemNumber = data_reader.Item("work item number")
Description = data_reader.Item("description")
ListBox1.Items.Add(New ListItem(Description, WorkItemNumber)
Loop
End If
As far as improvements, start by using a Using statement for the DB connection. In your code, if there is an exception while the database connection is open, it will never get closed. This is better...
Using conn As OleDbConnection = oWorkItem.GetDbConnection()
' Execute SQL and populate list...
End Using
The above code assures that your connection will be closed.
Then, turn on Option Strict and Option Explicit. This will force you to declare the Type for Description and WorkItemNumber and cast them as Strings when adding a ListItem. This will reduce run-time errors.
Finally, if this is anything but a small app you are doing as a learning experiment, you should read up on tiered application design. Your code is mixing UI, business logic, and data access in the same method. This is generally frowned upon.
Your "user interface" LoadWorkItem() method should ask a "core" method for a list of WorkItems.
Your core method should then ask a "data access" method for data.
The "data access" method should make the call to the database.
Happy coding.
Update: You can find excellent info about n-Tier architecture on MSDN. A good book to read once you grasp the fundamentals and have some confidence in .NET is Visual Basic .NET Business Objects.
Imports System.Data.SqlClient 'Reference The Sql Client
Public Class Form1
''Make sure to change the connection string below to your connection string this code only works for SQL DataBase. If Your connection String is wrong This will Not Work
Dim connString As String = "Data
Source=NameofYourSQLServer\SQLEXPRESS;Initial Catalog=NameOfYourDataBase;Integrated Security=True"
Dim tblDIV As DataTable
Dim daDIV As SqlDataAdapter
Dim dsDIV As New DataSet
Dim oCon As SqlConnection
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim oCon = New SqlConnection
oCon.ConnectionString = connString
dsDIV = New DataSet
' Select all Fields and order by ID or Replace * with name of Field
daDIV = New SqlDataAdapter("SELECT * FROM NameOfYourTable ORDER BY Id DESC", oCon)
'*** Define command builder to generate the necessary SQL
Dim builder As SqlCommandBuilder = New SqlCommandBuilder(daDIV)
builder.QuotePrefix = "["
builder.QuoteSuffix = "]"
Try
daDIV.FillSchema(dsDIV, SchemaType.Source, "DIV")
daDIV.Fill(dsDIV, "DIV")
tblDIV = dsDIV.Tables("DIV")
ListBox1.DataSource = tblDIV
ListBox1.DisplayMember = "NameOfTheFieldYouWanttoDisplay"
Catch ex As Exception
MsgBox("Encountered an Error;" & vbNewLine & ex.Message)
oCon.Close()
End Try
End Sub