event for when data is loaded from database

[adshocker]

hi all,

i have a textbox that i want to format the value and i placed it in the Validated event.. it works ok when a user enters a value but when data is being loaded from database, it doesn't format.

how do i do this?

thanks

[jmcilhinney]

The Validated event is only raised when the user tries to move focus away from a control, or else you explicitly call Validate or ValidateChildren in the form. Obviously none of those things are happening when you bind data.

That said, you shouldn't be formatting the data yourself if the control is bound. If you do then you're going to actually change the value stored in the data source. You should be letting the Binding handle that for you. Read the documentation for the Binding class and you'll see that there are several related to formatting. That way the value exposed by the Binding and displayed in the control can be different to the value in the data source.

[adshocker]

hi,

i'm having a bit of a problem with this... i tried following the sample here http://msdn.microsoft.com/en-us/libr...ng.format.aspx but i noticed that i needed to hard-code the datasource when creating a new binding.

this is actually a user control that i'm creating. i'ts like a textbox but with a property Format that i created.. then when the data is loaded in the textbox, it should be formatted based on the format mask in the Format property.

now, the problem i have is that when

Dim b As Binding = New Binding ("Text", ds, "customers.custToOrders.OrderAmount")

'The "ds" as well as the "customers.custToOrders.OrderAmount" are not yet specified. and the databinding is not yet added initially.. this is only added when i set the user controls databinding property at design time.

what approach should i take?

thanks

[jmcilhinney]

The Binding constructor is overloaded so you can specify the format when it's created, whether in code or in the designer. You can also set the format string in code at any time, e.g. when the Format property of your control changes.

[adshocker]

The Binding constructor is overloaded so you can specify the format when it's created, whether in code or in the designer. You can also set the format string in code at any time, e.g. when the Format property of your control changes.

hi,

i somewhat get your point by i have little idea on how to implement it.

can you provide any sample?

thanks

[jmcilhinney]

In post #3 you have shown the creation of a Binding. Can you change that code to include the setting of the format string? Have you read the Binding constructor documentation?

[adshocker]

hi,

ok so i now have this

        Dim ds As New DataTable
        Dim b As Binding = New Binding("Text", ds, "", True, DataSourceUpdateMode.OnPropertyChanged, DBNull.Value, DateTimeFormatMask)
        Me.DataBindings.Add(b)

at first i assumed that this binding will overwrite any databinding that has the same property but i get an error while doing so.

"This causes two bindings in the collection to bind to the same property.
Parameter name: binding"

so now i'm thinking this is not what i'm suppose to be doing.

any more tips?

thanks.

[jmcilhinney]

There aren't any collections that I'm aware of where calling Add twice will overwrite anything. If you have already added a Binding then you can't add another one for the same property. You have to set the format string when you create the one and only Binding for that property and/or you need to get a reference to that Binding and set the appropriate property. Do you know the format string when you create the Binding in the first place?

[adshocker]

Do you know the format string when you create the Binding in the first place?

not really. can you show me some sample syntax?

thanks

[jmcilhinney]

If you don't know the format string when you create the Binding then you can't set it when you create the Binding. You have to set it later. When you DO know the format string you simply get the desired Binding from the DataBindings collection and then set the appropriate property.

[adshocker]

hi,

the format string is set when provided at design time. i added a property for it. i can probably set a default format string.

[jmcilhinney]

If the format string is provided at design time then you DO know the format string when the Binding is created, so you can set the format string for the Binding in the designer. Select DataBindings -> Advanced in the Properties window.

[adshocker]

If the format string is provided at design time then you DO know the format string when the Binding is created, so you can set the format string for the Binding in the designer. Select DataBindings -> Advanced in the Properties window.

hi,

i'm lost...

here's all that i have for my usercontrol

Public Class DateTimeTextBox
    Inherits TextBox

    Public _Text As String
    Private _DateTimeFormatMask As String = "MM/dd/yyyy"

    Public Property DateTimeFormatMask() As String
        Get
            Return _DateTimeFormatMask
        End Get
        Set(ByVal value As String)
            _DateTimeFormatMask = value
        End Set
    End Property

    Private Sub DateTimeTextBox_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles Me.Validating
        Dim frm As New CalendarForm
        Try
            If Me.Text <> "" Then
                frm.FormatMask = DateTimeFormatMask
                Me.Text = UCase(Format(DateValue(Me.Text), DateTimeFormatMask))
            End If
        Catch ex As Exception
            Me.Text = ""
        End Try
    End Sub
End Class

when i reference this control into one of my forms and bind its Text property to a column in a datatable, when data is loaded and shown in the control, i want it in the format of my DateTimeFormatMask.

that part is not working and i don't know how to make it work.

thanks