I am doing a small system using Ms. Access (the database has more than 10 tables ) connecting to visual studio. I made a public class for opening the connection to the database so I can use it in every form. Everything is working and I can get the data from the database But any inserting or deleting data in forms, the database in ms access not getting the update. I can see the new records in forms but nothing in the database.
Imports System.Data.OleDb
Public Class dbconnectClass1
'create db connection
Private DBcon As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source=dental_clinic.accdb;")
'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 statics
Public recordcount As Integer
Public Exception As String
Public Sub ExecQuery(query As String)
'reset query status
recordcount = 0
Exception = ""
Try
'open connection
DBcon.Open()
'create db command
dbcmd = New OleDbCommand(query, DBcon)
'load params into dbcommand
params.ForEach(Sub(p) dbcmd.Parameters.Add(p))
'clear params list
params.Clear()
'excute command and fill dataset
DBDT = New DataTable
DBDA = New OleDbDataAdapter(dbcmd)
recordcount = DBDA.Fill(DBDT)
Catch ex As Exception
Exception = ex.Message
End Try
'close the database connection
If DBcon.State = ConnectionState.Open Then DBcon.Close()
End Sub
'include query and 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
This my code inside the forms:
Public Class NewExpense
Private access As New dbconnectClass1
' a varuble having the appointment Id to connect between 2 forms
Private appointmentNo As Integer
Private Function NoError(Optional report As Boolean = False) As Boolean
If Not String.IsNullOrEmpty(access.Exception) Then
If report = True Then MsgBox(access.Exception)
Return False
Else
Return True
End If
End Function
Private Sub Savebuttum_Click(sender As Object, e As EventArgs) Handles
Savebuttum.Click
Dim oDate As DateTime = Convert.ToDateTime(DateTimePicker1.Value)
access.addparam("#expensenme", expensenmtXT.Text)
access.addparam("#expensedetail", ExpenseDetailTXT.Text)
access.addparam("#expenseamount", ExpenseAmountTXT.Text)
access.addparam("#expensedate", oDate)
access.addparam("#expensepaidTo", paidtoTXT.Text)
access.ExecQuery("INSERT INTO Expense (Expenses_name, expense_details,
expenses_amount, ExpenseDate_Paid, ExpensePaid_To) Values (#expensenme,
#expensedetail, #expenseamount, #expensedate, #expensepaidTo);")
'report on errors
If Not String.IsNullOrEmpty(access.Exception) Then
MsgBox(access.Exception) : Exit Sub
'success
access.DBDA.Update(access.DBDT)
MsgBox("Expense Has been Added Successfully")
End Sub
End Class
Hum, you have this:
params.ForEach(Sub(p) dbcmd.Parameters.Add(p))
Great, we add the parmaters - looks good to go!!!
then, next line CLEARS all the work above!!! (the parameters are removed!!!!)
'clear params list
params.Clear()
Next up? Many will build a connection object, then a reader, and then a adaptor. But you ONLY need a data adaptor if you going to update a data table. if you just going to execute a command, then you don't need the data table, and you don't need a adaptor FOR that table. Adaptor = ability to modify a existing datatable (or dataset).
You are MUCH better to use the command object.
Why?
Because the command object has a connection object (don't need a separate one)
Because the command object has a data reader for you (no need for a whole data adaptor to JUST fill a table. And remember, you don't need a whole data adaptor UNLESS you are going to send/update a data table back to the database.
And because the command object has the command text, then you don't even need a variable for that!!!
And because all objects are in "one object", then really all you need is something to handy get you the connection.
So, for your insert example, we really don't gain by having that object, do we?
Ok, so here is your insert code without using those extra objects:
so in the following, I declare ONE variable, - the sql command object.
And do the insert
And as FYI? Your save button is not a save - but a insert button - every time you hit it, you will insert a new row. Lets deal with that issue in a bit.
So, here is our code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Using cmdSQL As New OleDbCommand("INSERT INTO Expense
(Expenses_name, expense_details,expenses_amount, ExpenseDate_Paid, ExpensePaid_To)
Values (#expensenme,#expensedetail, #expenseamount, #expensedate, #expensepaidTo)",
New OleDbConnection(My.Settings.TESTOLEDB))
With cmdSQL.Parameters
.Add("#expensenme", OleDbType.WChar).Value = expensenmtXT.Text
.Add("#expensedetail", OleDbType.WChar).Value = ExpenseDetailTXT.Text
.Add("#expenseamount", OleDbType.Currency).Value = ExpenseAmountTXT.Text
.Add("#expensedate", OleDbType.DBDate).Value = DateTimePicker1.Value
.Add("#expensepaidTo", OleDbType.WChar).Value = paidtoTXT.Text
End With
cmdSQL.Connection.Open()
cmdSQL.ExecuteNonQuery()
End Using
So things in above:
We have strong data typing and converstion.
Because of this, note how I did NOT have to create a separate date/time variable here.
Note the SAME for "money" or so called currency conversion - again strong data type by using parameters this way.
And is this a date only, or a date+ time value? If it is date, then
.Add("#expensedate", OleDbType.DBDate).Value = DateTimePicker1.Value
If it was/is a date + time, then this:
.Add("#expensedate", OleDbType.DBTimeStamp).Value = DateTimePicker1.Value
So, notice how all your object stuff REALLY did not help one bit, and in fact you did not really save code, and above actually had LESS variables defined to do the whole job.
Now, back to the insert issue/problem. (you save is doing a insert). But what about editing existing records?
So, I would suggest you work out the problem this way:
You create/get/have/assume a data row for the form.
The form takes the data row, fills the controls. You edit, and when you hit save, the data row is sent back to the datbase. So, once this works, then to add? Well, the add code will CREATE a new data row, save to database and THEN you send that new data row to the above eixsting form that can edit a data row, and can save a data row. So the form now is able to deal with both issues (adding vs editing existing). If the user dont' want the row, then you offer a delete button.
And REALLY nice is a data row means you don't deal with SQL, and don't deal with parmaters!!
So the code (desing pattern) I use is thus this:
dim da as oledbDataAdaptor
dim myTable as DataTable = MyRstEdit("SELECT * from tblHotels WHERE ID = " & lngID,da)
dim MyDataRow as DataRow = myTable.Rows(0)
' code to fill controls
txtHotelName.Text = MyDataRow("HotelName")
txtCity.Text = MyDataRow("City")
' etc. etc. etc.
Now to save? Well I put the values back into that DataRow like this:
MyDataRow("HotelName") = txtHotelName.Text
MyDataRow("City") = txtCity.Text
MyDateRow("BookingDate") = txtTimePick1.Value
da.Update(MyTable)
Notice how I don't have parameters, and even strong data type checking occurs for say the above Date/Time booking date column.
And the above is nice, since I don't have to deal with ANY parmaters to udpate a row of data.
The MyRstEdit routine looks like this and returns byREf a "da" (data adaptor).
Public Function MyrstEdit(strSQL As String, Optional strCon As String = "", Optional ByRef oReader As SqlDataAdapter = Nothing) As DataTable
' Myrstc.Rows(0)
' this also allows one to pass custom connection string - if not passed, then default
' same as MyRst, but allows one to "edit" the reocrdset, and add to reocrdset and then commit the update.
If strCon = "" Then
strCon = GetConstr()
End If
Dim mycon As New SqlConnection(strCon)
oReader = New SqlDataAdapter(strSQL, mycon)
Dim rstData As New DataTable
Dim cmdBuilder = New SqlCommandBuilder(oReader)
Try
oReader.Fill(rstData)
oReader.AcceptChangesDuringUpdate = True
Catch
End Try
Return rstData
End Function
So, now in vb.net, I actually find it is LESS code then even writing + using recordsets in MS-Access VBA code.
However, BEFORE you go down ANY of the above road?
Have you considered using the vb.net data binding features. Data-binding in vb.net means that you do NOT write ANY of the above code. it means that vb.net will do all of the dirty work, and write and setup ALL OF the code for you to edit data on a form. The end result is you don't write any code to update a table.
You do have to use + create a "data set". Once done, then you just drag controls onto the form, and you even get this. So you just drop in a dataset, table adaptor, Binding navagator, and you get this:
Note now the tool bar at the top (and you can place it on teh bottom if you wish). So you get this:
So that WHOLE form was created without having to write ONE line of code. And you can see we have navigation, edits and saves and even the ability to add. So, you can build up a editing form - and it thus becomes similar to say working in MS-Access and ZERO lines of code is required to build the above form.
However, if you ARE going to roll your own code? Then use a data row. That way you can shuffle data to/from the table, and NOT have to use parmaters and SQL update and insert statements - but ONLY have nice clean code in which you shove, or get values from that data row. .net will "write" all the update stuff for you.
First of all I´m developing a database with autosuggest box. I´ve created a database with DB Browser and imported data. I was reading documentation in C# how connect database and retrieve data. The issue is show up an exception error:
enter image description here
I´ve connected the database in properties with content option. I paste the code:
Public NotInheritable Class METARTAF
Inherits Page
Dim dbpath As String = Path.Combine(ApplicationData.Current.LocalFolder.Path, "airportsdb.sqlite3")
Dim conn As SQLite.Net.SQLiteConnection = New SQLite.Net.SQLiteConnection(New WinRT.SQLitePlatformWinRT(), dbpath)
Dim airportinfo As List(Of String) = Nothing
Public Sub New()
' This call is required by the designer.
InitializeComponent()
End Sub
Private Sub AutoSuggestBox_TextChanged(sender As AutoSuggestBox, args As AutoSuggestBoxTextChangedEventArgs)
Dim datairport As New List(Of String)
Dim retrieve = conn.Table(Of flugzeuginfo)().ToList
If args.Reason = AutoSuggestionBoxTextChangeReason.UserInput Then
If sender.Text.Length > 1 Then
For Each item In retrieve
datairport.Add(item.IATA)
datairport.Add(item.ICAO)
datairport.Add(item.Location)
datairport.Add(item.Airport)
datairport.Add(item.Country)
Next
airportinfo = datairport.Where(Function(x) x.StartsWith(sender.Text)).ToList()
sender.ItemsSource = airportinfo
End If
Else
sender.ItemsSource = "No results..."
End If
End Sub
Private Sub AutoSuggestBox_SuggestionChosen(sender As AutoSuggestBox, args As AutoSuggestBoxSuggestionChosenEventArgs)
Dim selectedItem = args.SelectedItem.ToString()
sender.Text = selectedItem
End Sub
Private Sub AutoSuggestBox_QuerySubmitted(sender As AutoSuggestBox, args As AutoSuggestBoxQuerySubmittedEventArgs)
If args.ChosenSuggestion Is Nothing Then
stationidtxt.Text = args.ChosenSuggestion.ToString
End If
End Sub
Anyone could help about this?
Before you query or insert into a table, you should CREATE it. This tells SQLite what columns you have and suggests datatypes (on other rdbms's you get actual data type enforcement but SQLite does not do that). If this is your problem, you will want to spend some time with the SQLite documentation on data types and the ability to hook them into your application.
On the other hand, as you seem to be trying to retrieve data, this suggess one of two things is wrong. Either you care connecting to the wrong db (in which case SQLite will usually helpfully create an empty db for you!) or else you are specifying the wrong table.
I have built a workflow designer that allows to enter a list of email addresses.Each email in the list needs to be an InArgument(Of String) so they can be individually edited/added using variables.
On my Activity, I have a property that is declared like so:
Public Property [To] As ObservableCollection(Of InArgument(Of String))
My designer is wired up and populating this collection properly.
However during the execution, I do not know how to get the run-time value for each InArgument that was added.
When we are executing the workflow and iterating for each InArgument added to the list, I attempted to get the value as shown below but that fails:
For Each toAddress As InArgument(Of String) In Me.To.ToList()
Dim emailToAddress As String = toAddress.Get(_Context)
Next
The error we get is “The argument of type '<type>' cannot be used. Make sure that it is declared on an activity” and type is a string in my case...
The error we get sort of make sense because we haven’t declared a property on the activity since it was added dynamically to the list and therefore cannot get the value using the syntax shown below:
The_Property_Name.Get(_Context)
Can someone help? I can't seem to find anything. Should I be doing a different approach?
I figured it out so I will answer my own question! All we need to do is explicitly add the collection items to the metadata by overriding CacheMetadata() method on the activity. This then makes it available to the workflow context.
First we add them to the context:
Protected Overrides Sub CacheMetadata(ByVal metadata As CodeActivityMetadata)
MyBase.CacheMetadata(metadata)
Dim i As Integer = 0
For Each item As InArgument(Of String) In Me.To
Dim runTimeArg As RuntimeArgument = New RuntimeArgument("TO" & i.ToString(), item.ArgumentType, item.Direction, False)
metadata.Bind(item, runTimeArg)
metadata.AddArgument(runTimeArg)
i = i + 1
Next
End Sub
Then when executing, we get the values like this
For Each item As InArgument(Of String) In Me.To
Dim email As String = _Context.GetValue(item)
Next
I am trying to render reports as PDF using the ReportExecution2005.asmx service endpoint on a SSRS 2012 server with MSSQL 2012 backend. When I call the Render method on the web service, I get the following error:
The parameter value provided for 'snapshotID' does not match the parameter type. ---> Microsoft.ReportingServices.Diagnostics.Utilities.ParameterTypeMismatchException: The parameter value provided for 'snapshotID' does not match the parameter type. ---> System.FormatException: String was not recognized as a valid DateTime
This error occurs with any report I try to render, snapshotID is not a parameter on the reports, and checking the configuration of the reports, they are not set up to be cached or use snapshots. We just recently moved from MSSQL 2005 to 2012, using the ReportExecution2005 endpoint with SSRS and SQL 2005 I never saw this error, it worked fine. I've tried adding snapshotID as a parameter with different values such as empty string, current time, etc. but that's apparently not what it's looking for. Below is the code I'm using to set up and call the Render method on the service. pstrExportFormat in my case will be "PDF"
Public Function ExportReport(pstrReportPath As String, plstParams As List(Of ReportParameter), pstrExportFormat As String) As Byte()
Dim lResults() As Byte = Nothing
Dim lstrSessionId As String
Dim execInfo As New reporting.ExecutionInfo
Dim execHeader As New reporting.ExecutionHeader
Dim lstrHistoryId As String = String.Empty
Try
Dim rs As New reporting.ReportExecutionService
Dim deviceInfo As String = "<DeviceInfo><PageHeight>8.5in</PageHeight><PageWidth>11in</PageWidth><MarginLeft>0.25in</MarginLeft><MarginRight>0.25in</MarginRight><MarginTop>0.25in</MarginTop><MarginBottom>0.25in</MarginBottom></DeviceInfo>"
rs.Credentials = System.Net.CredentialCache.DefaultCredentials
Dim params As New List(Of reporting.ParameterValue)
Dim param As reporting.ParameterValue
rs.Credentials = System.Net.CredentialCache.DefaultCredentials
For Each lInputParam In plstParams
param = New reporting.ParameterValue
param.Name = lInputParam.Name
param.Value = lInputParam.Value
params.Add(param)
Next
rs.ExecutionHeaderValue = execHeader
execInfo = rs.LoadReport(pstrReportPath, lstrHistoryId)
rs.SetExecutionParameters(params.ToArray, "en-us")
lResults = rs.Render(pstrExportFormat, deviceInfo, "", "", "", Nothing, Nothing)
Catch ex As Exception
Throw
End Try
Return lResults
End Function
Some additional information, this code is from an app built in VS 2012 Pro and targets the .NET 2.0 framework. I have tried targeting a newer framework but that gives me a different ReportExecutionService object altogether and I can't assign credentials in the same way, the Render method is also different in that case.
Any ideas on a workaround, or a better way to render reports programmatically? Thanks.
I had this exact same problem today and figured out that, in the LoadReport method, you want to make sure the HistoryID has a value of Nothing (null in C#). Right now, you're passing it in with an empty string - change the declaration to
Dim lstrHistoryId As String = Nothing
Or change your method call to
rs.LoadReport(pstrReportPath, Nothing)
I'm trying something out. I've got this system where a bunch of scripts are triggered at certain event handlers. This is used during the creation of Users in Active Directory.
So, what I think I need is a function that basically collects the properties of the user being processed into - hopefully, an object. And then returning that object and using it in other functions and subs. So that I can perhaps reach the properties I want using only "myObject.firstname" and that's it.
How can I create an object, create and set values in it and returning the entire object? Is this possible in VBS?
Edit: What would be best if I could create an Object that holds these properties and just being able to access them whenever I need to.
I'm basically after something like this:
Public Sub Main()
Set userStream = New objUser
msgbox objUser.firstname
msgbox objUser.lastname
msgbox objUser.username
End Sub
Edit: To explain furter, I have this library script which is called 'libGetUserProperties'
It's in this I want the function and Class. Then I just import this library script in the actual script that is run at runtime. Looks like this:
libGetUserProperties:
Public Function getobjUser(ByRef Request, ByVal From)
Dim thisUserObject
Set thisUserObject = New objUser
'If type = 0, data comes from AD
If From = 0 Then
thisUserObject.firstname = "some string"
thisUserObject.lastname = "some string"
End If
'If type = 1, data comes from Request stream
If From = 1 Then
thisUserObject.firstname = "some string"
thisUserObject.lastname = "some string"
End If
Set getobjUser = thisUserObject
End Function
Class objUser
Public firstname
Public lastname
Public username
End Class'
This is what the actual runtime Script looks like:
Dim libGetUserProperties
Set libGetUserProperties = ScriptLib.Load("Script Modules/Library Scripts/libGetUserProperties")
Sub onPreCreate(Request)
Dim userStream
Set userStream = New objUser
'Do whatever with objUser which contains all of the properties I'm after
End Sub
That’s not possible using VBScript, unless you want to dynamically generate the code for a class, including the properties, save that to file, and then execute that file as a script.
This is so much easier to do using JScript. Since Windows Scripting can handle JScript as well as VBScript, I’d recommend going that way.
If you definitely need VBScript, the best you can go for is a Scripting.Dictionary that would contain the properties as keys:
Dim dicUser
dicUser = CreateObject("Scripting.Dictionary")
dicUser("FirstName") = objUser.FirstName
which would allow you to access the first name as follows:
dicUser("FirstName")
Update
If you want to write a function which creates a dictionary and returns that, this is how to do it in VBScript:
Function RememberTheUser(Request)
Dim dicResult
Set dicResult = CreateObject("Scripting.Dictionary")
dicResult("FirstName") = Request.GetTheFirstName
Set RememberTheUser = dicResult
End Function
Which can then be assigned to some other variable:
Dim dicUser ' in the main section of the script, this means it's a global variable
Sub onPreCreate(Request)
' ...
Set dicUser = RememberTheUser(Request)
' ...
End Sub
Sub onSomethingLater()
WScript.Echo dicUser("FirstName") ' It's still accessible here
End Sub
In JScript, it’s a lot easier: just create a new object, and tack on new properties.
function readObject(dataSource) {
var result = {};
result.source = dataSource;
result.firstName = dataSource.firstName;
result['lastName'] = dataSource.FunctionThatGetsLastName();
}
Note that in JScript, object properties can be accessed using the object.property notation, but also through the object['property'] notation, which is very useful when you have dynamically-named properties. ('property' in the second notation is a string, and can be replaced by any expression that returns a string).
Keeping with VBScript, a disconnected recordset would work as well and is possibly faster than a dictionary; see here for an example.