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I've never implemented undo/redo functionality before, but it sounds like you've got the right idea.
Before you change the state of an object, you should clone it and push it into the Undo stack. When the user does an Undo, you should pop the object out of the Undo stack and overwrite the current object with it. The only gotcha you have to worry about here is if there are any objects still referencing the Undone object. If this is the case, then you may need to hold the undo-able object in some kind of container class so that you don't have to update all of the references. In fact, the container class should probably implement the Undo functionality.
I found an article on CodeProject covering an undo/redo framework written in C#. Perhaps it might be of use to you.
http://www.codeproject.com/csharp/undoredobuffer.asp[^]
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I want to select a picturebox control at runtime. Like in MS Word, If we insert any image, we can select it and perform operations on it (crop, rotate, resize, etc.).
I have created one user control in which I allow user to add imges (Placed in picture box of 100 X 100 size).
I could move the control at runtime by capturing Mouse related events. Now I want to resize it say by dragging the small sqares that should appear at its corners.
Can I use GDI+ to achieve this? Can anybody suggest me any code or APIs?
Thanks in advance...
Anil
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Hi,
Im using VB 6.0.. I try to Print few words to the Zebra Label Printer..But doens't seems to print at all..
COde is :
Printer.Print "^XA"; Printer.Print "^MD10"
Printer.Print "^LH0,0^FS"
Printer.Print "^BY2,3.0^FO20,2^BCN,54,N,Y,N^FR^FDMirudhubashini^FS"
Printer.Print "^FO20,59^A0N,28,37^CI13^FR^FDWomens center^FS"
Printer.Print "^FO20,65^A0N,28,37^CI13^FR^FDCoimbatore^FS"
Printer.Print "^PQ1"
Printer.Print "^XZ"
Printer.EndDoc.
Either I see Status in Printer Queue as "Spooling".. and if i give Printer.Enddoc ..Nothing I can see in Printers Queue
All ^XA and similar words are for Label Printer ZPL Language
Pls help
-- modified at 6:01 Saturday 6th May, 2006
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You are trying to send a control character but it is sending a literal string with an ^ in it.
'--8<------------------------
Ex Datis:
Duncan Jones
Merrion Computing Ltd
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Hye All ,
I 'm facing a problem in changing the DSN file at run time , I ' m working on Crystal Report 8.5 , I ' ve a report which comes from a procedure , I 've 2 Year Wise SQL Database ,At Run Time User Selects the Year and my database connection gets change now I want to change the report DSN at run time so that I won't be needing to change all my Reports. I just want to change DSN File Values (User Id, Paddword,Server , database name )on run time , Can Anyone help me ?
Mannu
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hi all
I want to disable Guest Account in WinXP in VB.can anyone tell me the API to use??
thanx in advance
"Every morning I go through Forbes list of 40 richest people in the world. If my name is not in there, I go to work..!!!"
-- modified at 5:07 Saturday 6th May, 2006
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if there's one row in the datagrid. and i want the value of row(0) column(0)
using DataGrid1.Item(DataGrid1.CurrentRowIndex(), 0)
what i want here is to delete the current selected row.
it's working fine, unless the final row....
the error is : out of range
so what i can do.
Militiaware
Faris Madi
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Code looks choppy there; shouldn't it be like this:
myDataSet.myTable.DefaultView(myDataGrid.CurrentRowIndex).Delete()
myDataSet.myTable.AcceptChanges
??? I wouldn't actually delete stuff from the grid as it is the underlying dataset you're trying to manipulate. Also make sure you apply "AcceptChanges" or the DS will not delete the record.
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in other words...
i want to get the value of column(0) and row(i)
when i try this (column(0) row(0)), an exception occure "out of range"
Militiaware
Faris Madi
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Do you want to get the value in a cell or delete the row? To simply get the value:
bindingContext(myDataset, "myDataTable").Current("myField")
This will give you the value in the current field.
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Hi
I am using WMI to get information about running processes on a local machine in vb6. But in the case of cpu_percantage, it always shows 99% for wmiprsve process (which is in fact collecting data) and all other processes have 0% cpu usage!
I checked it in Task Manager, it shows only 2% for the named process and shows reasonable usages for other running processes....
Is there any way that I can get cpu percentages from WMI? Or any other ways to do so in vb6?
Thanks
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you can change the header of the column in datagird in (Web Project)
but in Win Application and datagrid doesn't provide the ability to change the headers....
my question, how to change the header?
Militiaware
Faris Madi
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try opening the help file.
look for "DataGridTableStyle.MappingName Property" it may prove to be exactly what you are looking for.
modified 1-Aug-19 21:02pm.
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that what i'm looking for..
in the web datagrid control you can find it....but not in the win datagrid control.
i tried to change the headers from the datagrid .... no solution where found.
i tried to change the headers from the dataset .... no solution where found.
and i believe there's a soution.. but where.....?????
Militiaware
Faris Madi
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i have developed a web application in which i have make use of a single web form which will ivoke web service. In that form, i have used 3 textboxes and a dropdown list box. In that list box i have included 4 services as items. once if i choose a service/ operation, it does the operation which i want but when i try to choose another service/operation, it automatically doubles the amount of items already added into that drop down list box. y it happens? can any one know abt it?.. if so can u plz tell me that what i have to do for eleminating that?
thanks,
with regards,
K.Vijaya
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It sounds like you are adding the items on each postback. You should only do that when you create the page the first time, e.g. when IsPostBack is false.
Translation:
it snd lk u r addn d items on each postbk. u shd only do dat when u create d page d first time, e.g. when IsPostBack is false
---
b { font-weight: normal; }
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ya its working fine now.. what u gave here is really helpful to me.
thanks a lot
K.Vijaya
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My computer used to give me low virtual memory warning when i work in vb.net and sql server 2000 simultaneously.
Then i incresed the size of virtual mem. After that the warning didn't come again. But now it has started again.
Plz smbdy tel me the solution to this problem.
Plzzzzzzzzzz 
Thanks.
Swati
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Private Sub TreeView1_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterSelect<br />
<br />
TamakiLabs.Show()<br />
Lab131.Hide()<br />
Lab134.Hide()<br />
Lab203.Hide()<br />
<br />
If TreeView1.SelectedNode.Name = "Lab 723-131" Then<br />
Lab131.Show()<br />
ElseIf TreeView1.SelectedNode.Name = "Lab 723-134" Then<br />
Lab134.Show()<br />
Else : Lab203.Show()<br />
End If
im wanting my system to show 4 different datagridviews, yet it only shows Lab134 datagridview no matter which node i click. I dont where my code is wrong, can someone please give me a clue as to where i have my mistake in my code.
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Hi
I am trying to write an application that can read arabix text file
but he dose not do than ????????????
i try the same code in reading english file and it success !!!!!!!!
how i can solve this problem
please help me ............................
khaleel
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Can you be more spesific?
What type of data are you trying to extract?
Can you post a part of the code?
Isaac Sasson
"I hate it. Java sucks. And Java's generics suck harder. And in general, Java just sucks."
- David Stone, The Lounge (May 1st 2006)
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Hi
it is an text file
code
System ::String *strData = S"" ;
System ::String *m_strFileName= S"" ;
System ::IO ::StreamReader inFile =
new System ::IO ::StreamReader( m_strFileName ) ;
strData = inFile.ReadToEnd( ) ;
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Hi Everyone:
I have not been receiving any ressponses lately, but we will try again.
I’m trying an experiment in ADO database connections. I have two MS-Access 2000 databases. One is password protected, the other isn’t.
I have two functions to make connections to the database using ADO.
With login data:
Public Function Jet_Connect_Login(ByVal strProv, ByVal strDB, ByVal strUser, ByVal strPasswd) As Integer
On Error GoTo Jet_Connect_Login_Err
Set cnnMainDb = New ADODB.Connection
With cnnMainDb
.ConnectionString = "Provider=" & strProv & ";Data Source=" & strDB & _
";User ID=" & strUser & ";Password=" & strPasswd & ";"
.Open
Jet_Connect_Login = .State
End With
Jet_Connect_Login_Exit:
Exit Function
Jet_Connect_Login_Err:
Select Case Err.Number
Case adErrObjectOpen
If cnnMainDb.State = 1 Then
cnnMainDb.Close
Set cnnMainDb = Nothing
End If
Resume Jet_Connect_Login_Exit
Case Else
Msg = "Error in Startup module - Establish_Connection function. " & vbCr & _
"Error # " & Str(Err.Number) & " was generated by " _
& Err.Source & vbCr & Err.Description
MsgBox Msg, , "Error", Err.HelpFile, Err.HelpContext
If cnnMainDb.State = 1 Then
cnnMainDb.Close
Set cnnMainDb = Nothing
End If
Resume Jet_Connect_Login_Exit
End Select
End Function
Without login data:
Public Function Jet_Connect_Std(ByVal strProv As String, ByVal strDBName As String) As Integer
On Error GoTo Jet_Connect_Std_Err
Set cnnMainDb = New ADODB.Connection
With cnnMainDb
.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strDBName
.Open
Jet_Connect_Std = .State
End With
Jet_Connect_Std_Exit:
Exit Function
Jet_Connect_Std_Err:
Select Case Err.Number
Case adErrObjectOpen
If cnnMainDb.State = 1 Then
cnnMainDb.Close
Set cnnMainDb = Nothing
End If
Resume Jet_Connect_Std_Exit
Case Else
Msg = "Error in Startup module - Establish_Connection function. " & vbCr & _
"Error # " & Hex(Str(Err.Number)) & " was generated by " _
& Err.Source & vbCr & Err.Description
MsgBox Msg, , "Error", Err.HelpFile, Err.HelpContext
If cnnMainDb.State = 1 Then
cnnMainDb.Close
Set cnnMainDb = Nothing
End If
Resume Jet_Connect_Std_Exit
End Select
End Function
The Connection function without the logon works fine, but the one requiring log on information is giving me the following error:
Error in Startup module – Establish_Connect function.
Error# -2147217843 was generated by Microsoft JET Database engine.
Cannot start your application. The workgroup information file is missing or opened exclusively by another user.
Thank you,
Quecumber256
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Hi, does anyone out there know how to create a new class that inherits form System.ComponentModel.Design.CollectionEditor.CollectionForm? I've checked online and it seems that this can be done in C#, but I can't find any resources out there that explain how to inherit this class in vb.net. Thank you in advance.
C#:
public class MyCollectionEditor : CollectionEditor
{
protected class MyCollectionForm : CollecitonEditor.CollectionForm
{
}
}
VB.Net - Does not work, error msg:
"System.ComponentModel.Design.collectioneditor.collectionform is not accessible in this context because it is 'Protected'"
public class MyCollectionEditor
inherits CollectionEditor
protected class MyCollectionForm
inherits CollecitonEditor.CollectionForm
end class
end class
eatwork
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