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The usefulness of interfaces is very similar to abstract base classes. The purpose of an interface is as a contract to consumer objects that a particular method or property (or event for that matter) will be present - including its signature. You want consumer objects to know that an object implementing the ILogEntry interface will have an AddEntry method (or several overloaded versions of it). With an abstract base class, this concept is no different. I usually only use the abstract base class when there is code common to the derived classes and I want to eliminate duplication. However, due to being limited to single inheritance, the interface becomes again useful.
Consider some of the included interfaces with the framework: IEnumerable promises that there is a GetEnumerator method (which returns an object that implements the IEnumerator interface) and nothing more. But in those instances where one wishes to enumerate a collection, this is what is required and expected.
As to your particular problem, it appears that you have two method signatures - and your interface supplies neither. This is what you need for this example:
Public Interface ILogEntry
Public AddEntry(varOne as String)
Public AddEntry(varOne as String, varTwo as String)
.
.
.
End Interface
So long as the method signature matches, the compiler won't complain.
α.γεεκ Fortune passes everywhere.
Duke Leto Atreides
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I had tried (at least I thought that I had) to to that was when I tried to implement the interface I looked like I was forced to impliment BOTH the AddEntry methods in my class.
I think my problem was that NONE of the parameters to the methods matched in my case.
I was trying to use:
AddEntry(entryText As String)
AddEntry(varName As String, varValue As String)
Perhaps if I used the naming that you example did where at least one of the vars matched things would have been better?
I actualy am testing a version that uses an abstract base class now and it seems to be working well. I actually found some implimentation that was common so it ended up helping in reducing code duplication as well.
Paul Watson wrote:
"At the end of the day it is what you produce that counts, not how many doctorates you have on the wall."
George Carlin wrote:
"Don't sweat the petty things, and don't pet the sweaty things."
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I have a form which contains two MSHFlexGrids which are side by side. The reason for having two grids is so that I can simulate a Freeze Pane like in Excel. Both grids are populated from the same RecordSet but from different fields.
My question is when the user selects a row in one grid and highlights that row, how can I get the code to select the same row in the other grid and also highlight it?
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The checkbox in access is called Completed. i am trying to populate a datagrid based on a SQL statement in VB, including this checkbox, but in the grid, it is only being displayed like a text field - is there anything i can do about this? here is my code for it - any help would be appreciated!
Dim checkSQL As String
checkSQL = "SELECT OrderGenerate.OrderNumber, Client.Company, OrderGenerate.Completed " & _
" FROM Client INNER JOIN OrderGenerate ON Client.ClientCode = OrderGenerate.ClientCode " & _
" WHERE (((OrderGenerate.OrderDate)=" & dToday & "))"
Set RS = Conn.Execute(checkSQL)
Adodc1.RecordSource = checkSQL
DataGrid1.Visible = True
Set DataGrid1.DataSource = Adodc1
Adodc1.Refresh
DataGrid1.Refresh
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No, use a 3rd party control. Or use a ListView and add controls to edit the ListView above it with a Checkbox for the Field you'd edit.
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I was just wondering if anyone else gets this problem too. When I have several ComboBoxes on a Form, and I resize it, all the Text in ever combobox (even if they do not currently have the Input Focus) becomes Highlighted! It's very annoying! The only way to get rid of it then is to Tab through each ComboBox.
Any ideas on how to resolve this?
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I know .NET is different than 6 wrt control arrays. But shouldn't I be able to capture the CLICK on the following (fragment)?
Dim contArray(2) as Button
for i = 0 to 1
contArray(i) = new Button
contArray(i).tag = i
controls.add(contArray(i))
next i
...
private sub contArray_CLICK (...)
or something that lets me get the tag or index of the button clicked.
-David
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Here is an example of how to do it in both VB.NET and C#
CodeProject Clickety[^]
Please keep in mind that I do not like how the article is formatted, but the content is ok.
Paul Watson wrote:
"At the end of the day it is what you produce that counts, not how many doctorates you have on the wall."
George Carlin wrote:
"Don't sweat the petty things, and don't pet the sweaty things."
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Thanks, works pretty good.
If I want to add the control array to a panel instead of a form, how would I declare the control?
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Thanks, works pretty good.
If I want to add the control array to a panel instead of a form, how would I declare the control?
assuming a Panel1 on the main form,
Dim ControlArray as ButtonArray(Panel1) 'doesn't work since Panel1 is not a "form" container
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Instead, change the Form reference to be an "IContainer" control since all Controls and Forms inherit from IContainer.
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Thanks for the reply. But I'm new to .NET. If you mean, have the main form inherit from System.Windows.Form.IContainerControl it doesn't work. At least I get an error that says classes can inherit only from classes.
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I'm trying to send email from within VB.NET and I get the following error: "Could not access 'CDO.Message' object." when I try to send the message. Here's a brief summary of my config:
Running Windows 2000, SP3 on our Company Ethernet with MS Echange email server
Code:
Imports System.Web.Mail<br />
<br />
'These 3 were added while I was debugging the problem, but they don't seem to help<br />
Imports CDO <br />
Imports MAPI <br />
Imports MSMAPI<br />
.<br />
.<br />
Dim MailMsg As System.Web.Mail.MailMessage<br />
Dim MailSrvr As System.Web.Mail.SmtpMail<br />
.<br />
.<br />
.<br />
.<br />
MailMsg = New System.Web.Mail.MailMessage()<br />
MailMsg.From = "from@email"<br />
MailMsg.Body = "Test Message!"<br />
MailMsg.Subject = "HI"<br />
MailMsg.To = "to@email"<br />
Try<br />
MailSrvr.Send(MailMsg)<br />
Catch err As Exception<br />
Debug.WriteLine(err.Message)<br />
End Try
Without fail, I get the error message. It seems to me that the code is right, but I must be missing a service or config somewhere. I've searched high and low on the web, MSDN, and .NET's sorry documentation but can't find out what's up.
Any ideas?
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Have you set the MailSrvr.SmtpServer property yet??. You need to set it to the IP of your Mail Server.
Notorious SMC
The difference between the almost-right word & the right word is a really large matter - it's the difference between the lightning bug and the Lightning
Mark Twain
Get your facts first, and then you can distort them as much as you please
Mark Twain
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Thank you for your help. It seems so obvious  , but none of the examples or references I had found, actually said that. I set it to the name of our mail server, and it worked.
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txtFind is a textbox that is used for search purposes (ie if a value is entered and the text box looses focus, a grid appears displaying a range of results). However, if no value is entered and it looses focus, i want the focus to be set on another text box:
If txtFind.Text = "" Then
txtCustomerCode.SetFocus
Exit Sub
End If
However, this generates the error: "Invalid procedure call or argument", is there anything i can do to alleviate this? thanks in advance for any help!let me know if any additional detail is required.
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Hi !
I get this same error when the control to which I want to set the focus is not visible.
Jerome
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First of all, make sure you have another Control that can get Focus (i.e. It must be Enabled and if there is an "AllowFocus" property, set it to true).
Then in the Validate Event:
If (txtFind.Text.Length = 0) Then txtNext.Focus():Exit Sub
'Otherwise, populate Grid Here
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hello all...
i am looking for an API for VB6 to interface the parallel port...i.e. i want to input and output data from external electronic circuits to a visual basic 6 program...
does anyone know where i can get such an API ??
Thanx
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Hello,
I'm using VB.NET and i was just wondering, how can i make a window flash 3 times; when the user clicks on it while the property Enabled is set to false.
Any help would be greatly appreciated. Thanks.
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u can use the flashWindowEx api function defined in user32.lib
enjoy
<marquee>rishabhs
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Could you please be more specific. I'm not that good with APIs, and I have never done this before. Thanks.
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actually its very simple to do
just open the api viewer (either thru addin menu in the ide or from program group (tools)
then load file win32api.txt in the api viewer (file->open)
add declaration for FlashWindow in ur code
another alternate way is to search for file WIn32api.txt (in visual studio folder\common tools) and copy decl of the function in ur code
now all u have to do is to just call the function FlashWindow anywhere in ur code and see ur window flashing once
put the first param as ->
and 2'nd param is to specify whether window inverts its state after flasing or not (See MSDN)
if u want to flash n times then
add FlashWindowEx function along with FLASHWINFO struct in same way as i told u
i hope now u can make it work
enjoy
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I'm having problems with my VB ole control. I inserted the (wordpad) object inside the form, and added the code doverb to display it at run time, but the menu items are not displayed. If i run the program with doverb and use double click on the control the menu is displayed. Any ideas.
Thanks
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I'm having problems with my VB ole control. I inserted the (wordpad) object, and added the code doverb to display it at run time, but the menu items are not displayed. If i run the program with doverb and use double click on the control the menu is displayed. Any ideas.
Thanks
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