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I finally solved this thing with a solution that I like. Basically, I use the Observer Design Pattern to create an ObservedThread class.
In VB.NET, I implement this using events. The class has 2 events: Started and Ended.
The class is really simple:
' we can't derive from Thread so we use composition.
' Unfortunately, this means that we have to create the Thread
' interface in this class, but for this example, we'll only
' expose a Start method.
Imports System.Threading
Public Class ObservedThread
Protected Thread As Thread
Protected StartProc As ThreadStart
' some useful events:
Public Event StartedArgs(ByVal Thread As ObservedThread)
Public Event Started()
Public Event EndedArgs(ByVal Thread As ObservedThread)
Public Event Ended()
Public Sub New(ByVal StartProc As ThreadStart)
Me.StartProc = StartProc
Thread = New Thread(AddressOf ThreadProc)
End Sub
Protected Sub ThreadProc()
StartProc()
RaiseEvent EndedArgs(Me)
RaiseEvent Ended()
End Sub
Public Sub Start()
RaiseEvent Started()
RaiseEvent StartedArgs(Me)
Thread.Start()
End Sub
End Class
And let's assume you have an independent form, that you want to appear while the thread executes, and close when the thread finishes. The form has nothing to do with the thread. It's a simple form, that has a timer ticking every few millisecs:
dim frm as New frmPleaseWait
Dim th As New ObservedThread(AddressOf DoSomethingHeavy)
AddHandler th.Started, AddressOf frm.Show
AddHandler th.Ended, AddressOf frm.Close
th.Start()
That's it. Works great.
/=/=/=/= Sagmam =\=\=\=\
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Is this VB6 or VB.net?
In VB6 simply add a doevents to the code
eg
dim frm as new frmWaitMsg
frm.Show
doevents
GenerateReport
frm.Close
I think there is something similar in .net but it is application.doevents
Jon
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Anybody to help connecting a VB6 program to access a database in SQL Server?
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You should use ADO reference or ADO control to connecto your SQL server. The suggest step for you (if you are the beginner), try to connect to database by using a wizard. Then learn from the connection string. If you have some problem to remember the connection string, try to read the information from here.[^]
APO-CEDC
Save Children Norway-Cambodia Office
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Thank you very much sir. I'm a beginner, could you please tell me how to get the ADO wizard? i got some codes(strings) from some books and it doesn't work. it says 'object not found' etc. is it something related to user connection? really i don't know how to do it. please help me.
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first is to create a reference to the ado library. to do this select references from the project menu and tick the 'microsoft ActiveX Data Objects 2.7 Library' box.
The Code to connect to SQL Server and Create a basic recordset is as follows:
dim cn As ADODB.Connection
dim rs as ADODB.Recordset
Set cn = New ADODB.Connection
cn.ConnectionTimeout = 25
cn.CommandTimeout = 120
cn.Provider = "sqloledb"
cn.Properties("Data Source").Value = YourServerName
cn.Properties("Initial Catalog").Value = YourDatabaseName cn.CursorLocation = adUseClient
cn.Properties("Integrated Security").Value = "SSPI" 'If using Windows integrated security
cn.Open
set rs = new ADODB.Recordset
rs.open "Select * from yourTable",cn
You now have a basic recordset
Dont forget to close everyhing and set to nothing when your done.
Sorry if it sounds basic but you did say you are a beginner
Jon
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Dear RamBhatt, an example from jonathan15 is good. Try to do it and learn the process step by step. But according to the code, if you copy and paste it in your project don't forget to add the following two lines at buttom of your code:
rs.Close<br />
Set cn = Nothing
If you still have a problem with this example, let me know I will explain you in another way to help you understand with this issue.
APO-CEDC
Save Children Norway-Cambodia Office
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'Thank you very much sir. it worked as expected. i've some doubts.
'i don't have any ref books at present thatz why i'm putting questions here.
'i chose ActiveX Data Objects 2.5 - is it required to change 'sqloledb' to some other driver?
'in ODBC the setting was SQLServer Authentication, but it still worked, why?
'could you please tell me the difference between RDO and ADO?
to komsot man-sir u told me about wizard whatz it? how to use it? is it something related to 'user connection'?
'the following code, which i got from a book, gave error. could you please tell me why?
the RDODatabase is a class that i got from book. the relevant methods i've pasted down
history
1. when i ran the code as it is it showed 424 object not found
2. when i tried to debug (i don't know much about objects to use class,pls help me) it showed runtime error 40002, data source name not found and no default driver specified. this errmsg was not from my errpara! it was from the class errhandler.
----------------
Dim objDatabase As RDODatabase
'-------my code begins
Public Sub ReadFromStud()
On Error GoTo errPara
'connect to remote DB
'--my code to debug!!
Set objDatabase = New RDODatabase
objDatabase.Connect "ODBCTest", "test", "sa", "sqluser"
'-----
'RDODatabase.Connect "ODBCTest", "test", "sa", "sqluser"
'select query
'RDODatabase.Execute "SELECT * FROM Stud"
Do Until RDODatabase.EOF 'repeat till eof
Debug.Print RDODatabase("idx"), RDODatabase("Name")
RDODatabase.MoveNext
Loop
Exit Sub
errPara:
MsgBox Err & Chr(13) & Err.Description
End Sub
'----my code ends
'the class def is as follows...
'Public Function Connect(Optional strDSN As String, Optional strDatabaseName As String, Optional strUserName As String, Optional strPassword As Variant) As Long
'Call connect to attach to an RDO/ODBC datasource and be happy.
' If ConLiveFlag Then Exit Function
' On Error GoTo Connect_Error
' If strDSN <> "" Then mvarServerName = strDSN
' If strDatabaseName <> "" Then mvarDatabaseName = strDatabaseName
' If strUserName <> "" Then mvarUsername = strUserName
' If Not IsMissing(strPassword) Then mvarPassword = strPassword
' If mvarQueryTimeout = 0 Then mvarQueryTimeout = DEFAULT_QUERYTIMEOUT
' If mvarLoginTimeout = 0 Then mvarLoginTimeout = DEFAULT_LOGINTIMEOUT
'
' If ConLiveFlag Then Call Disconnect
'
' With mvarRDOConnection
' .Connect = ODBCConnectionString
' .LoginTimeout = mvarLoginTimeout
' .CursorDriver = rdUseOdbc
' On Error Resume Next
' .QueryTimeout = mvarQueryTimeout
' On Error GoTo Connect_Error
' .EstablishConnection rdDriverNoPrompt 'open the connection, if named DSN does not exist, ODBC will prompt the user to create one or select a different one
' End With
'
' DoEvents
'
' ConLiveFlag = True
' Connect = 0
'Exit Function
'Connect_Error:
'
' Call HandleError
'
'End Function
'Public Sub Execute(sSQL As String, Optional DatasetType As Variant, Optional Mute As Boolean)
'If the Mute param is True, then no dataset is returned from the server, as in an INSERT query or
'DROP query.
'On Error GoTo Execute_Error
'
' If mvarRDOConnection.rdoQueries.Count Then mvarQueryObject.Close
' Set mvarQueryObject = mvarRDOConnection.CreateQuery(QSQL, sSQL)
' If IsMissing(DatasetType) Then DatasetType = DATASETTYPES.DYNAMIC
'
' 'If we are mute, execute without results
' If Mute Then
' mvarQueryObject.Execute
' Else
' If DatasetType = DATASETTYPES.FORWARD_ONLY Then
' Set mvarRDOResults = mvarQueryObject.OpenResultset(rdOpenForwardOnly, rdConcurReadOnly)
' ElseIf DatasetType = DATASETTYPES.DYNAMIC Then
' Set mvarRDOResults = mvarQueryObject.OpenResultset(rdOpenKeyset, rdConcurRowVer)
' End If
' DoEvents
' boolResultsAvailable = True
' End If
'
'Exit Sub
'
'Execute_Error:
'
' Call HandleError
'
'End Sub
'-------------------
'Public Sub MoveNext()
'On Error GoTo MoveNext_Error
' mvarRDOResults.MoveNext
'Exit Sub
'MoveNext_Error:
' Call HandleError
'End Sub
'Private Sub GenDatabaseError()
' Dim MSG As String
' MSG = Err.Description + "|"
'
' For Each DataErr In rdoErrors
' MSG = MSG + "[" & DataErr.Number & "]" & DataErr.Description & Chr(13)
' Next DataErr
'
' lErrorNumber = Err.Number
' sErrorMessage = MSG
'
' Err.Raise lErrorNumber, ERROR_SOURCE, sErrorMessage
'End Sub
'Private Sub HandleError()
' Dim lErrNum As Long
' Dim sErrMsg As String
' lErrNum = Err.Number
' sErrMsg = Err.Description
' If lErrNum = 40002 Then
' Call GenDatabaseError
' Else
' Err.Raise lErrNum, ERROR_SOURCE, sErrMsg
' End If
'End Sub
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I can answer for you for only question that I know and base on documentation.
1. Difference between RDO and ADO.
RDO stand for Remote Data Objects
Remote Data Objects implement a set of objects to deal with the special requirements of remote data access. RDO implements a thin code layer over the ODBC API and driver manager that establishes connections, creates result sets and cursors, and executes complex procedures using minimal workstation resources. Although RDO is also accessed by DAO when your code creates an ODBCDirect Workspace object, documentation for this implementation can be found by searching for specific ODBCDirect topics.
Note RDO and the RemoteData control are designed to be used only in 32-bit operating systems such as Microsoft Windows 95 (or later) or Microsoft Windows NT.
With RDO and the RemoteData control, your applications can access ODBC data sources without using a local query processor. This can mean significantly higher performance and more flexibility when accessing remote database engines.
By using RDO, you can:
Create simple cursorless result sets, or more complex cursors.
Run queries and process any number of result sets.
Execute stored procedures that return result sets with or without output parameters and return values.
Execute action queries that perform data manipulation or data definition operations.
Limit the number of rows returned or processed.
Monitor all of the messages and errors generated by the remote data source without compromising the executing query.
Enable synchronous, asynchronous, or event-driven asynchronous processing so your application isn't blocked while lengthy queries are executed or the current row pointer is repositioned.
ADO stand for ActiveX Data Object
Solutions for Local Data Access
The Issue
You want a simple, consistent application programming interface (API) that enables applications to gain access to, and modify a wide variety of data sources. A data source may be as simple as a text file, as complex as a cluster of different types of databases, or something yet to be invented. Furthermore, the API should not presume the means of gaining access to and manipulating the data source.
Although these are your specific requirements, the typical data source is a relational database that supports the Open Database Connectivity (ODBC) standard and is manipulated with commands written in Structured Query Language (SQL).
The general solution Microsoft offers to this problem is OLE DB, a set of Component Object Model (COM) interfaces that provide uniform access to data stored in diverse information sources. However, because the OLE DB application programming interface is designed to provide optimal functionality in a wide variety of applications; it does not meet the requirement for simplicity.
You need an API that is a bridge between the application and OLE DB. ActiveX Data Objects (ADO) is that bridge.
The Solution
ADO defines a programming model—the sequence of activities necessary to gain access to and update a data source. The programming model summarizes the entire functionality of ADO.
The programming model suggests an object model—the set of objects that correspond to and implement the programming model. Objects possess methods—which perform some operation on data—and properties—which either represent some attribute of the data or control the behavior of some object method.
Associated with objects are events—which are notifications that some operation has occurred, or is about to occur.
Basic ADO Programming Model
ADO provides the means for you to perform the following sequence of actions:
Connect to a data source. Optionally, you can ensure that all changes to the data source occur either successfully or not at all.
Specify a command to gain access to the data source, optionally with variable parameters, or optionally optimized for performance.
Execute the command.
If the command causes data to be returned in the form of rows in a table, store the rows in a cache that you can easily examine, manipulate, or change.
If appropriate, update the data source with changes from the cache of rows.
Provide a general means to detect errors (usually as a result of making a connection or executing a command).
Typically, you will employ all these steps in the programming model. However, it is worth noting that ADO is flexible enough that you can do useful work by executing just part of the model. For example, you could store data from a file directly into a cache of rows, then use ADO resources solely to examine the data.
(The source of this document were took from MSDN Library January 2000)
2. About the wizard
It look like the wizard but it just 2 importance step that you need to understand, first select the connection type and second choose the database. To understand this follow this step:
1. Create a new blank project in vb6.
2. Go to Project menu and click on Component submenu.
3. When the Component dialog box appear scroll to Microsoft ADO Data Control 6.0 (OLEDB) and checked it.
4. An ADO data control appear on the tool box and click and draw it on your form.
5. When an ADO data control appear on the form right click on it and choose ADODC Property.
6. From the property dialog box of ADO data control in the "Source of Connection" frame you will see three option. The first one is "Use Data Link file" the second one is "Use ODBC data source name" and the third one is "Use connection string".
7. Choose the third option (Use connection string) and click the build button.
8. You will see the Data Link Property dialog box appear with a difference type of data that you want to connect. If you want to connect to SQL server database you can click on "Microsoft OLE DB Provider for SQL Server" and click on "Next >>" button. The next tab of property dialog box appear with 3 step for you to follow. The first one is "Select or enter the server name:" click on the drop down list to choose the server name that contain SQL database install on it. The second step is "Enter information to log on server", you can choose two option (SQL or Windows authenication). This example I prefer Windows authenication. And the third step is select database on the server. I choose master database (just an example, master database is the core database of SQL server. You should not modified to it in case of necessary). Then click on "Test connection" button. If you see message box said that "Test connection successed." then it is working properly.
9. Click on OK button twice and you will see the connection string in the text box "Provider=SQLOLEDB.1;Integrated Security=SSPI; Persist Security Info=False;Initial Catalog=master;Data Source=APOCEDC".
Learn from here try to customize the code with any database that you create in SQL server. Then you will see how it is working.
Hope it is work!!! and wish you good luck in programming!!! ![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif) 
APO-CEDC
Save Children Norway-Cambodia Office
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Thanks a lot sir. i got the way and it is really useful. now i can make a Library program which can be used in a network than in a stand alone system. a long way to go i know. again thanks.
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Hello there
Can anybody tell me how to use a VB6 form application on my Pocket pc.
thanks
murtuza
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Try to read the information from here.[^]
APO-CEDC
Save Children Norway-Cambodia Office
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how can i delete contents of history folder.i've been able to access it but not been able to delete websites in today . can someone tell me how can i do that. thanx in advance
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Do you want to delete it from any application that you build or just delete by manually. If delete by manually, try to go to IE option. On the first tab (the General tab) click on "Clear History" button. This button just clear the list of day that it appear in IE history pane. If you want to clear the file that you have browse on your computer you have to click on "Delete Files..." button. This will clear the cache file that you browse any website before. Hope this work!!!
APO-CEDC
Save Children Norway-Cambodia Office
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thanx but i know it manually.i have even done that from application but the problem is that it clears the "Temporary Internet Files" folder only and not the history folder which actually has a calendar today which caches sites i want to gain access to that folder and delete today calendar. if u can help do reply, thanx.
nitin
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In IE click on History button, then it will display history pane. If you want to delete the today history, try to right click on Today folder and click delete. Make sure that you already clear the file in IE option (General tab).
APO-CEDC
Save Children Norway-Cambodia Office
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Hi all.
I have a quick question about how to determine the color of text based on the background color of the form. My form allows the user to change the BackColor property, but if they select a darker color I would like all the text labels to "lighten up" for them. Windows does this with the text labels of the desktop icons and I'm just wondering how it's done.
As near as I can tell I'll have to just examine the RGB values of the form color and maybe invert them - RGB(255 - R, 255 - G, 255 - B). Is there an easier way do to it though, that I'm not aware of?
Please let me know. Thanks.
"Go to, I’ll no more on’t; it hath made me mad." - Hamlet
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Hi,
There is a problem with me.
I want to open a report created in CR9 thru VB 6 but without using CRViewer.
Actually, i want the behavior of Crystal Report control.
i.e. report is opened in a seperate window and it stays alive even if vb application is closed.
Is there any kind of "Crystal Report control" for CR9, too ?
Plz, respond asap.
Awaiting your reply....
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Anybody here know how to retrieve the Topmost Visible row of a Datagrid?
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i want to locate a location of property using Maps. I want to show the property info through navigating Maps. Do u have any idea, how can i achieve this task.
if u know about MapPoint then tell me how can i create own maps in it
thanks.
RAK
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Oh, sorry I thought you wanted the titlebar one,
ok, then check here:
.NET Framework Class Library
Help.ShowHelp Method
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemWindowsFormsHelpClassShowHelpTopic.asp
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thanks for you're help...
Unfortunately I still can't find the answer.
All the examples points to loading a help file or pointing to an index or using the help.showhelp class.
All I want to do is "Emulate" the ? HelpButton on the title bar. Now as soon as I found some reference to that, MS says that this procedure cannnot be used in your code  DOH!
I thought it might be as easy as raising an event like Showhelp.click ...
There has to be a way ¿
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Hello,
I am beginner in VB.net, kindly guide me in a problem.
I have a file that is written in a language other than English e.g., In Hindi or URDU.
I want to read and display the contents of that file in my program.
How can i do that.
Thanks in advance.
Regards,
Eshban
EsHbAn BaHaDuR
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VB .NET
I am looking for a way to raise the ShowHelp event for context sensitive help when the user presses a toolbar button.
I want the button to behave exactly the same as the ? on the title bar.
Can anyone help?
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