I am adding a handler on each form to validate all textboxes for empty strings.
I have a class that has a procedure for validation
Sub NonEmptyValidate(sender as Object, e as System.ComponentModel.CancelEventArgs)
dim _errorProvider as ErrorProvider
dim _txtBox as TextBox
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What is the difference between ErrorProvider.Clear() and ErrorProvider.SetError(tBox,vbNullString)
Is there a preference for one or the other?
[code] Combine method is working successfully,But Remove method not working Successfully .Now I want to remove delegate SingleCall2 on Button2_Click,I want that only SingleCall1 and SingleCall3 are invoked.
View 4 Repliesfrom the documentation we have this: Multicast Delegate: Represents a multicast delegate; that is, a delegate that can have more than one element in its invocation list.
so am i right to say that Multicast delegate is no different from a normal delegate other than the fact that it has arguments. so System.Action is a 'normal' delegate whereas System.Action(T)(Byval obj as T) is a multicast delegate?
I've created a Delegate that I intend to call Async.
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Code:
Public Class SendPings
Shared Sub New()
AddHandler Post.Saved, AddressOf Post_Saved[code].....
I get a error" Method 'Private Shared Sub Ping(item As BlogEngine.Core.IPublishable, itemUrl As System.Uri)' does not have a signature compatible with delegate 'Delegate Sub WaitCallback(state As Object)'.
I would like to ask how to clear the ErrorProvider in VB.net 2003? ErrorProvider.Clear() isn't working in vb2003. i know it's very simple
View 2 RepliesI'm having troubles with my errorprovider and i already found out what the problem is - the textbox is bounded twice (Display Member and Value have different binding sources) and so the errorprovider is showing the same error twice. If i remove one binding source,everything is fine.Any suggestions?Oh - I'm validating the columns in my DataSet.vb with DataTable_ColumnChanged Sub with table.setColumnError().Another problem ->I have a field (decimal) in my dataset that is optional (can be null). But if the user writes something in and then deletes it so that the textbox is empty, the errorprovider is showing the error "Input string was not in a correct format."
View 1 RepliesI have put my business logic in a partial class as suggested in best practices. One of the conditions is that one of four fields of a row has have a value. Setting the errorprovider has no problems when creating a new row in the new row event. All the textboxes in the form show the error condition.
Dim ErrorString As String = "A value is needed for at least one of the " & vbCrLf & "Gallon, Fuel, Oil, or Misc fields"
e.Row.SetColumnError("Gallons", ErrorString)[code]....
The logic that sets them back to a no error condition though only sets the currently focused control in the form to no error. When the error is corrected.
MyFuelRow.SetColumnError("Gallons", "")
MyFuelRow.SetColumnError("FuelCost", "")[code]....
How can you reset multiple column errors at once?
How can I reference the errorprovider on another form from a module.
Sample Code:
Sub
leaveOptionalTBTextValidation(ByRef TBControl
As custTextBoxControl,
ByRef intMaxChars
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I'm having an issue with getting the errorprovider to work in a database application where I have put the error provider logic in a partial class and have a combobox value change.Either I set the bindings so that it works but any navigation in the binding navigator then updates the value of that combobox on every next previous etc or it never fires until the save. So there is no way to change the errorprovider setcolumnerror string to something new with out saving on every navigation move. After changing the selection in the combobox the row does shows dirty (rowstatus) so there is databinding but it doesn't fire the ColumnChanged event like textbox and other controls. Is there a way to keep all this in the business logic in a partial class?
Partial Class reportexecDataSet
Partial Class fuellogDataTable
Private Sub fuellogDataTable_ColumnChanged(ByVal sender As Object, ByVal e As
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I have an ErrorProvider on a form with a DataGridView.The Binding Source for the DGV points at a single table in the DataSet (which hooks up to an underlying Access DB).The table has two columns:
1) Autoincrement PK
2) Text field, <=25 chars, unique, can't be Null or empty string
I test for string length (>0 and <=25) in the DataSet.Table.RowChanging event.If it's out of range then I use e.Row.SetColumnError, that passes the error to the ErrorProvider / DGV on the correct row and DataSet.HasErrors returns True. All good, no problems.
I test for uniqueness in the DataSet.Table.ColumnChanging event.If it's not unique I can set the error with either e.Row.SetColumnError or e.Row.RowError; Now it gets complicated since sometime this makes the ErrorProvider / DGV show the error and sometimes not, it depends on whether the DataSet keeps the Unique = True constraint of the underlying DB.
Why would I have the DataSet be False for Unique when the DB is True for same constraint? So that the user interaction with the form has the minimum of dialogue box based interuptions. I am trying to design a system whereby all issues / errors are reported
to the user as they interact with the form in a subtle way, allowing them to keep working but trapping errors before any attempt to Save from the DataSet to the DB.
So, if the DataSet keeps the unique constraint then when you insert the new (duplicate) row the DGV throws its DataError event, a default dialogue appears, behind which the DGV has the ErrorProvider icon on the correct row. However, since the DataError event
causes the problematic change to be rolled back, the new row is removed and the error disappears.
If I change the DataSet requirement to Unique = False, then SetColumnError does not cause an ErrorProvider icon to be shown and DataSet.HasErrors returns False. I can improve upon this slightly by using RowError, this causes DataSet.HasErrors to return True but the ErrorProvider icon still does not show.Further, when using Unique = True on the DataSet, and editing an existing row to be a duplicate of another, the behaviour is the same, DGV.DataError event, roll back of the change but the ErrorProvider icon remains, despite the row no longer being a duplicate and DataSet.HasErrors returns True. The text of the the ErrorProvider tooltip is the one from SetColumnError, not RowError.So, the behaviour of SetColumnError is affected by the state of the DataSet field Unique constraint?
Unique = True
SetColumnError affects the DGV / ErrorProvider and DataSet as expected.
(RowError behaviour unknown)
Unique = False
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I'm using the ErrorProvider in VB.Net (2005) which is associated with a BindingSource that is bound to a custom object that I have created. This custom object contains a date field that has a "Date" data type that. I am using a "TextBox" to bind the date field in my form. My issue is, whenever the TextBox loses focus and is blank, "String not recognized as a valid DateTime" is displayed by the ErrorProvider and the focus can't be changed to any other control on the Form. It's good that the ErrorProvider validates entries on Date fields by default (I didn't set up my custom object to display this particular error for the date), but it should allow blank values. I want the user to be able to have a blank date with no error message displayed. How can this be done using a Date field bound to a TextBox?
View 2 RepliesIs there any way to turn the damned error provider off when i try to close the form using the windows close button(X). It fires the validation and the user has to fill all the fields before he can close the form..this will be a usability issue because many tend to close the form using the (X) button. i have placed a button for cancel with causes validation to false and it also fires a validation.
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I am trying to write a VB.NET alternative to a C# anonymous function.I wish to call Threading.SynchronizationContext.Current.Send which expects a delegate of type Threading.SendOrPostCallback to be passed to it. The background is here, but because I wish to both pass in a string to MessageBox.Show and also capture the DialogResult I need to define another delegate within. I am struggling with the VB.NET syntax, both from the traditional delegate style, and lambda functions.My go at the traditional syntax is below, but I have gut feeling it should be much simpler than this:
Private Sub CollectMesssageBoxResultFromUserAsDelegate(ByVal messageToShow As String, ByRef wasCanceled As Boolean)
wasCanceled = False
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how the various elements that help you handle errors work together. Have tried several options and can't make head nor tail of it. The underlying table has two columns, an autoincrement integer and a text column with the following settings:
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We would like to have 2 ErrorProviders for a DataGridView. The standard ErrorProvider and another WarningProvider with a different icon. Also is it possible to Left Justify the standard ErrorProvider icon in specific DataGridView cells?
View 1 RepliesJust had to remove remove statics and use Delegates refering to class. i have got a little problem in one of my project.I need help to resolve it.My application Connect several FTP server with the same Class.I'm using TCPclient for few specifics Commands.The problem : All threads call the same TCPclient wich can't connect several server at once.I would like to create a New TCPclient for each thread.
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I'm trying to remove individual nodes from their parent, I tried the Remove method but it doesn't seem to be working. How is this done? Is this a bug or what?
Sub Main()
Dim xml =
<?xml version="1.0" encoding="utf-8"?>
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While reading this threadthe code sample there came from MSDN, which was used to demonstrate the use of a delegate. I know what Delegates are. And I know how they work when it comes to things like crossing threads and even sinks.... how ever, the sample given is a simplecontrived example, and I'm wondering why/when would I use a delegate in this situation? Or in any situation? In my head, it seems it would have been easier/cleaner to call the function pointed to directly...
View 18 RepliesI heard once that .net introduced an already defined delegate with no parameter that we could use instead of creating one.
View 1 RepliesI came across a snippet of C# code which is very useful. I am trying to convert it to VB.NET, but can't seem to.
timer.Tick += delegate { panel.Children.Add(source); timer.Stop(); };
Is it possible to translate this to something similar in VB?
I have below code in C#:
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I'm having trouble converting a C# delegate to VB.NET.
How can this be done?
public MainForm()
{
InitializeComponent();
_twain = new Twain(new WinFormsWindowMessageHook(this));
_twain.TransferImage += delegate(Object sender, TransferImageEventArgs args)
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how can I convert the following code from C# to VB without exposing "variable" as global variable.
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I'm in the process of converting some existing code to VB. However, I'm running into a bit of a snag. It seems that in C#, a delegate can have a return value, but not so in VB. So my question is, how would I convert the following VB code to handle this?.[code]
View 3 Repliesim developing a way of calculationg differentil equations in VB 2008 using the 4th order ruge-kutta method. I pursched a book by Jack Xu called "Practical WPF Graphics programming".
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how this is written in VB.NET? This was an example I found on [URL]
ThreadPool.QueueUserWorkItem(delegate
{
var channelFactory = new ChannelFactory<ISimpleService>("*");
var simpleService = channelFactory.CreateChannel();
var asyncResult = simpleService.BeginGetGreeting("Daniel", null, null);
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I am using this delegate to invoke my methode:
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for few solutions it work outs well but not for the following code. I find an error when executing the following code. I find an error :
ErrorMethod 'Public Sub test()' does not have the same signature as delegate 'Delegate Sub DataRowChangeEventHandler(sender As Object, e As System.Data.DataRowChangeEventArgs)'.C:UsersKashifDocumentsVisual Studio
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