Passing an Index value to a Function

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As per the Subject, that is what I want to do.

I am experimenting here, so I know the code is not perfect & may not even work at all, but I am working on it bit by bit and at the moment I just need to get the Index value into the Function

I have a Loop as follows ...

VB

For Ix = 0 To myArrayLen - 1
    If myXml1.Value.Chars(Ix) = "Y" Then
        myWordData = GetNewsletterHeader(Ix)
        MsgBox(myWordData)
    End If
Next

and a Function as follows ...

VB

Function GetNewsletterHeader(ByRef Ix As Int16) As String
    Dim myXml2 As XmlTextReader = New XmlTextReader(myDataFolder + "NewsLetter Items.xml")
    myItem = "Item" + Ix
    Do While (myXml2.Read())
        If myXml2.IsStartElement() Then
            If myXml2.Name = myItem Then
                GetNewsletterHeader = myXml2.Value.ToString
            End If
        End If
    Loop
End Function

It currently throws an exception "Conversion from string "Item" to type 'Double' is not valid.", presumably because the Ix is a pointer rather than a real value.

Posted 30-Jan-13 4:02am

Gary Heath

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CHill60 30-Jan-13 10:21am

Include your definition of Ix and on which line does the exception get thrown

3 solutions

Solution 2

1. Remove the ByRef and replace with ByVal.

Function GetNewsletterHeader(ByVal Ix As Int16) As String

2. Ensure that Ix is declared as Int16 in the scope of the For..Next loop

3. In the Function GetNewsLetterHeader, add the following line

Dim myItem as string

4. Change the assignment to myItem to

myItem = "Item" & Ix.ToString

5. Add the following line as the very first line of the Visual Studio document file that contains this code

Option Strict

6. Let us know which line gets the error and what the Visual Studio Debugger displays for the values of the variables that are involved in the error.

Posted 30-Jan-13 4:31am

Mike Meinz

Updated 30-Jan-13 4:41am

v8

Solution 1

You don't show your declaration of myItem, but I assume it is something like:

VB

Dim myItem as Double

Since the compiler error is talking about converting a string constant "Item" to a double, and why it can't do it. Since Ix is an Int16, myItem must be a double.

Posted 30-Jan-13 4:30am

OriginalGriff

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CHill60 · Accepted Answer · 2013-01-30T04:33:00

Solution 3

Ok, the exception is particularly nicely worded and you wouldn't get the problem with C# but the problem is with

myItem = "Item" + Ix

You should be using

VB

myItem = "Item" + Ix.ToString

Posted 30-Jan-13 4:33am

CHill60

Comments

Gary Heath 30-Jan-13 10:45am

So simple !!! Thank you CHill60 ...