[RESOLVED] [2005] For Each Loop

[obscuregirl]

Hi

I'm having some problems with a For Each loop and wondered if anyone could help.

I have a combo box (coPropID) on my screen that has been preloaded with the IDs of all people in my database. I have another combo called coProp that has been preloaded with the names of all the people on the database in the same order, so that index 0 of coPropID contains the ID for the person whose name appears in the index 0 of coProp. When this screen is loaded to show an existing record, I retrieve the person's ID from the database and want to be able to use it to find the name in the coProp combobox.

I'm using a For Each loop to find the id retrieved from the database (which has been assigned to a string called supStr) and find the index within the combobox that this ID sits on. I then want to set the index of the coProp combobox to that index and display the name.

However, it is not working. I have tried to step through it, but it appears to look at the first item in the combo, not finding a match and not looping through to any of the other items. My code appears below:

If supStr IsNot "" Then
            comboColl = coPropID.Items()
            For Each thisObject As String In comboColl
                If thisObject <> supStr Then
                    'go to next thisObject
                Else
                    ind = coPropID.Items.IndexOf(supStr)
                    Exit For
                End If
            Next thisObject
            coProp.SelectedIndex = ind
        End If

[Grimfort]

From what I understand, you dont actually need a for loop at all.
You can use the
ind = coPropID.Items.IndexOf(supStr)
line to tell you what the index of that item is, check if its a positive number (ie its in the list) and if so, use it to select the other one.

The for loop looks ok to me, but without seeing the data, cant tell what its doing.

[obscuregirl]

From what I understand, you dont actually need a for loop at all.
You can use the
ind = coPropID.Items.IndexOf(supStr)
line to tell you what the index of that item is, check if its a positive number (ie its in the list) and if so, use it to select the other one.

The for loop looks ok to me, but without seeing the data, cant tell what its doing.

Thanks Grimfort. I've tried just using the IndexOf line but am getting the same problems.

If supStr IsNot "" Then
            ind = coPropID.Items.IndexOf(supStr)
            If ind >= 0 Then
                coProp.SelectedIndex = ind
            End If
        End If

supStr is variable that is local to my sub and is being set shortly before the above section of code. However the line "If supStr IsNot "" Then" has a warning attached to it saying that supStr is being used before it has been assigned a value. The IndexOf function produces a result of -1 and despite my checking if ind is greater than or equal to 0, it still goes into this piece of code and assigns the selectedIndex of coProp to -1!!! Am I missing something here?! I'm totally confused!

[bmahler]

How are you populating this Combobox? If you use a dataset as the source then you can bind the values to the box using the DisplayMember and ValueMember

Dim ds As Dataset
'Code to Fill Dataset With names and ID's
Me.ComboBox1.DataSource = ds.Tables(0)
Me.ComboBox1.ValueMember = "ID" 'The field name for the id
Me.ComboBox1.DisplayMember = "Name" 'The field name for the name

You can then just get the SelectedValue for the item that is the text that you want to return the ID

[GaryMazzone]

Instead of using two comboxs I use on combo and an array of integers to hold the primary key of the row from the database select query. I redim the array with preserve keywork then place the PK integer value there and the words into the combobox. When someone selects something from the combobox I check if the selectedindex is greater then -1 if it is I use the selectedindex to get the same intem from the array: int = arPKs(me.combobox.SelectedIndex)

[Grimfort]

The IndexOf function produces a result of -1 and despite my checking if ind is greater than or equal to 0, it still goes into this piece of code and assigns the selectedIndex of coProp to -1!!! Am I missing something here?! I'm totally confused!

If this is happening you got problems . Is "ind" actually declared as an integer? Thats the only thing I can think of. You shouldnt be able to do that anyway if you have option explict on.

[obscuregirl]

If this is happening you got problems . Is "ind" actually declared as an integer? Thats the only thing I can think of. You shouldnt be able to do that anyway if you have option explict on.

ind is declared as an integer and option explicit is on!!

I've even tried:

If ind <> -1 Then

but it just seems to ignore this check completely! it's just weird.

[Grimfort]

Step through the code with breakpoints and watch it, this sounds strange. Are you editing on the fly and not recompiling your code? Ive not played about with edit-and-continue but I have heard of "difficulties" .

[obscuregirl]

How are you populating this Combobox? If you use a dataset as the source then you can bind the values to the box using the DisplayMember and ValueMember

Dim ds As Dataset
'Code to Fill Dataset With names and ID's
Me.ComboBox1.DataSource = ds.Tables(0)
Me.ComboBox1.ValueMember = "ID" 'The field name for the id
Me.ComboBox1.DisplayMember = "Name" 'The field name for the name

You can then just get the SelectedValue for the item that is the text that you want to return the ID

thanks, but there is a reason why I can't use a dataset. Can't remember what it was now, but know that some time ago it was deemed not to be an option!

I was originally doing it based on the name of the assigned person (Title Initials Forename Surname) which seemed to work until I noticed that it actually didn't work for anyone who didn't have a forename specified! I thought doing it on the ID might be more reliable!

[obscuregirl]

Step through the code with breakpoints and watch it, this sounds strange. Are you editing on the fly and not recompiling your code? Ive not played about with edit-and-continue but I have heard of "difficulties" .

ummm.... not quite sure what you mean... VS won't let me edit the code when I'm stepping through it. I have to stop it running to edit... is that what you mean?

[bmahler]

hmmm. Seems strange that you would not be able to use a dataset. I can't think of any reasons not too off the top of my head, but anyway,
Another option is to use a class to store your id and name

'The Classs
Public Class dataItem
    Private _id As String
    Private _value As String
    Private _value2 As String
    Private _value3 As String
 
    'Constructors
    Public Sub New(ByVal id As String, ByVal value As String)
        _id = id
        _value = value
    End Sub
 
    Public Sub New(ByVal id As String, ByVal value As String, ByVal value2 As String)
        _id = id
        _value = value
        _value2 = value2
    End Sub
 
    Public Sub New(ByVal id As String, ByVal value As String, ByVal value2 As String, ByVal value3 As String)
        _id = id
        _value = value
        _value2 = value2
        _value3 = value3
    End Sub
 
    'Properties
    Public ReadOnly Property ID() As String
        Get
            Return _id
        End Get
    End Property
 
    Public ReadOnly Property Value() As String
        Get
            Return _value
        End Get
    End Property
 
    Public ReadOnly Property Value2() As String
        Get
            Return _value2
        End Get
    End Property
 
    Public ReadOnly Property Value3() As String
        Get
            Return _value3
        End Get
    End Property
 
    'Overrides
    Public Overrides Function ToString() As String
        Return Value
    End Function
 
End Class
 
 
'Implementing it
Me.ComboBox1.Items.Add(New DataItem(ID, Name))
 
'Retrieving value
 
Dim ID As Integer
 
For I As Integer = 0 To Me.ComboBox1.Items.Count - 1
    If Me.ComboBox1.Items.Item(i).ToString() = Value Then
        ID = CType(Me.ComboBox1.Items(i), DataItem).ID
        Exit For
    End If
Next

[obscuregirl]

Thanks everyone for your help. Much appreciated. I've done it a completely different way now because the logic-defying behaviour was freaking me out a little!