Iterate through Array

[Dave Kreskowiak]

Larry White wrote:

After modifying line 3 with x = CStr(arrList2.Item(i)) , I receive the following error: "Value of type 'String' cannot be converted to '1-dimensional array of String'." X is defined as: Dim x() As String

It's always best to copy and paste the actual code you're using. Don't post a sample and then tell use what you did to it. It makes it very difficult to see what you actually did. x doesn't have an Item property, so the code should look more like this:

For i = 0 To x.GetUpperBound(0)
    Console.WriteLine(x(i))
Next i

Notice, you don't need CSTR. This is because your x array is an array of Strings. Why try to convert a String to a String?? Also, to get your code to show up in the nice beige box and retain some formatting, paste it between <pre> and </pre> tags.

Dave Kreskowiak Microsoft MVP - Visual Basic

[Guffa]

Why do you declare the x variable as an array? As you are going to use it to reference a string, declare it as a string: Dim x As String

--- single minded; short sighted; long gone;

[Larry White]

Thank you. The tags do make it alot easier to read.

LWhite

[Larry White]

I adjusted my code as follows:

Dim x As String
For i = 0 To arrList2.Count - 1
x = arrList2.Item(i)
strName = arrList2.Item(i)

I now get the qty of data entries in my database equal to the number of names I select in the textbox, but the last entry is blank. If I select 3 names, I get the first 2 database entries with the names, but the last one is blank (name field). It appears the first iteration leaves strName blank. Thanks again for the assistance.

LWhite

[Guffa]

The code that you have shown is correct, although reading the same value from the array twice into separate variables doesn't look like what you want to do. The problem that you talk about is in the part of the code that you haven't shown. Unless you show it, I can't tell you much more than that it's wrong...

--- single minded; short sighted; long gone;

[Larry White]

Here are the other relevant parts of my code. I build the textbox entries with the following, which also drops the selected names into the array:

Private Sub lbName_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbName.SelectedIndexChanged
editName.Text = Nothing
For i = 0 To lbName.SelectedItems.Count - 1
arrList2.Add(strName)
With arrList2
.ToArray()
End With
editName.Text = editName.Text & lbName.SelectedItems(i) & vbCrLf
strName = lbName.SelectedItems(i) & vbCrLf
Next
End Sub

Here is my complete code that is supposed to create a new database record with each iteration of the name array:

For i = 0 To arrList2.Count - 1
strName = arrList2.Item(i)
x = arrList2.Item(i)

Dim strCommandText As String = "INSERT INTO Orders(OrderDate, DeliverDate, DeliverLocation, Name, Special, Comments, Rate, EMPLID, LoggedIP)" _
& "VALUES('" & strOrderDate & "','" & strDeliverDate & "','" & strDeliverLocation & "','" & strName & "','" & strSpecial & "','" & strComments & "','" & strRate & "','" & strEMPLID & "','" & strLoggedHost & "')"

Dim cmd As New SqlClient.SqlCommand(strCommandText, SqlConnection1)
cmd.ExecuteNonQuery()
Next

Thank you for your assistance.:)

LWhite

[Guffa]

The code look pretty strange... Where do you declare the strName variable? You use the strName variable, but you haven't given it any value before using it. You give it a value later in the loop, so it will have a value for the next iteration of the loop, but not for the first iteration. Also, the value that you assign to it in the last iteration will never be used. You create an array from the items in the list arrList2, but you just throw the array away without doing anything with it. Why?

--- single minded; short sighted; long gone;

[Larry White]

When the form opens, I have a "Dim strName As String" along with other variables. Thank you, you got me thinking and I rearranged my code. It works now. Here is what it looks like now:

Private Sub lbName_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbName.SelectedIndexChanged
editName.Text = Nothing
tbEmplid.Text = Nothing
For i = 0 To lbName.SelectedItems.Count - 1
strName = lbName.SelectedItems(i) & vbCrLf '.ToString & vbCrLf
arrList2.Add(strName)
With arrList2
.ToArray()
End With
editName.Text = editName.Text & lbName.SelectedItems(i) & vbCrLf
Next
End Sub

Note: I moved the "strName = lbName.SelectedItems(i) & vbCrLf" line above the "arrList2.Add(strName)" line, instead of being the last line. It sequences through nicely now. I trash the array, is it is only for the record creation and not needed after that. Thank you again! I hope posting this code will help someone else!:cool:

LWhite

[Guffa]

That looks better. :) Any variables you can, you should declare locally inside the method, instead of declaring them in the class. Local variables are allocated on the stack, are very inexpensive, and only exist when they are needed. Class variables increases the size of your form object, and they take up memory even when they are not used. You still have some strange code...

With arrList2 .ToArray() End With

This does the same as:

Dim s() as String
With attList2
s = .ToArray()
End With
s = Nothing

In other words, the only thing that it does is wasting time and memory resources. You create one array each iteration of the loop, and not any of the arrays are ever used for anything.

--- single minded; short sighted; long gone;

[Larry White]

Thank you for your suggestions. I rearranged most of my variables to be local. I have another issue you may be able to help me on. I'm using the following code to perform a SQL SELECT to combine the first & last name, and the employee ID number to be used in a listbox. The user selects multiple names that are transfered to a textbox. When they are selected, the array is created, which is used to create a record in a SQL table (one entry per name). The problem I have is, I need to update the Employee ID field but haven't found the right code to extract the "emplid" data. The name field works fine.

Dim sql1 As String = "Select (LastName + ', ' + FirstName) As Name, emplid FROM Users ORDER BY LastName"

Dim strCommandText As String = "INSERT INTO Orders(OrderDate, DeliverDate, DeliverLocation, Name, Special, Comments, Rate, EMPLID, LoggedIP)" & "VALUES('" & strOrderDate & "','" & strDeliverDate & "','" & strDeliverLocation & "','" & strName & "','" & strSpecial & "'" & ",'" & strComments & "','" & strRate & "','" & strEMPLID & "','" & strLoggedHost & "')"

Private Sub lbName_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbName.SelectedIndexChanged
Dim i As Integer
editName.Text = Nothing
For i = 0 To lbName.SelectedItems.Count - 1
arrList2.Add(lbName.SelectedItems(i))
With arrList2
.ToArray()
End With
editName.Text = editName.Text & lbName.SelectedItems(i) & vbCrLf
Next
i = Nothing
End Sub

Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click

    Dim i As Integer
    Dim r As String
    Dim x As String

    editComments.Clear()
    strComments = editComments.Text

    Try
        SqlConnection1.Close()
        cnn1.Close()
        SqlConnection1.Open()

        ' Create a name array from editName textbox; Used to create a new record for each name

        For i = 0 To arrList2.Count - 1
            strName = arrList2.Item(i)
            x = arrList2.Item(i)

            Dim strCommandText As String = "INSERT INTO Orders(OrderDate, DeliverDate, DeliverLocation, Name, Special, Comments, Rate, EMPLID, LoggedIP)" & "VALUES('" & strOrderDate & "','" & strDeliverDate & "','" & strDeliverLocation & "','" & strName & "','" & strSpecial & "'" & ",'" & strComments & "','" & strRate & "','" & strEMPLID & "','" & strLogge