I need to take some code written in VisualFoxPro and rewrite it in VB. Having no experience with FoxPro I asked about a few commands used in the code and found one of particular use: scatter memvar, which made individual variable from columns in a table. Does VB have an equivalent function, or do I need to create each variable with a Dim statement?
Edit: I should have mentioned that I'm looking to use this to propagate datatables, very sorry. Later in the VFP program insert into memvarmatches the variables to their respective columns. I'm looking to avoid the need of a method along the lines of:
For Each row As DataRow in MyTable
row.Item(0,i) = myVar1
row.Item(1,i) = myVar2
'etc.
i += 1
Next
Sadly, the above is how I do most of my data entry.
Edit: In response to @DRapp's comment, I am using VB to read a .xin file and form an access data table from its code. There are two "collections" in the .xin file that are of interest to me: <NamedSymbologyCollection> and <FeatureStylesCollection>. Both of these collections are in the same line of the file, so I've written code to go tag-by-tag, pick out the information I want, and add it to a temporary data table.
Do Until reader.EndOfStream
content = reader.ReadLine
For Each code In content
If content.Length > 0 Then
crntTag = content.Substring(0, content.IndexOf(">") + 1)
If crntTag.Contains("/FeatureStyleCollection>") Then
Exit Do
End If
If crntTag.Contains("<NamedSymbology ItemName") Then
wholeTag = GetFullLine(content)
xinCompile.Rows.Add()
For Each entry In wholeTag
lcstring = wholeTag.Substring(0, wholeTag.IndexOf(">") + 1)
If wholeTag.Length = 0 Then
Exit For
End If
If lcstring.Contains("<NamedSymbology ") Then
SymbName = GrabCodeElement(lcstring, "ItemName=")
SymbDesc = GrabCodeElement(lcstring, "Description=")
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
xinCompile.Rows(i).Item("symbName") = SymbName
xinCompile.Rows(i).Item("symbDesc") = SymbDesc
ElseIf lcstring.Contains("<BasePointSymbology ") Then
CellLayer = GrabCodeElement(lcstring, "CellLayerName=")
CellName = GrabCodeElement(lcstring, "Name=")
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
xinCompile.Rows(i).Item("cellLayer") = CellLayer
xinCompile.Rows(i).Item("cellName") = CellName
ElseIf lcstring.Contains("<LineSymbology ") Then
LineSymb = GrabCodeElement(lcstring, "<LineSymbology LayerName=")
LineSymb = LineSymb.Substring(15, LineSymb.Length - 16)
xinCompile.Rows(i).Item("lineSymb") = LineSymb
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
Else
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
End If
Next
i += 1
ElseIf crntTag.Contains("<FeatureStyle ItemName") Then
wholeTag = GetFullLine(content)
j = 0
featStyles.Rows.Add()
For Each entry In wholeTag
lcstring = wholeTag.Substring(0, wholeTag.IndexOf(">") + 1)
If wholeTag.Length = 0 Then
Exit For
End If
If lcstring.Contains("<FeatureStyle ") Then
SymbName = GrabCodeElement(lcstring, "ItemName=")
SymbDesc = GrabCodeElement(lcstring, "Description=")
For Each item As DataRow In xinCompile.Rows
If SymbName = item.Item("symbName") Then
found = True
Exit For
End If
j += 1
Next
If found = True Then
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
Else
Exit For
End If
xinCompile.Rows(j).Item("symbDesc") = SymbDesc
ElseIf lcstring.Contains("<SurveyFeature ") Then
NumCode = GrabCodeElement(lcstring, "NumericCode=")
DTMexclude = GrabCodeElement(lcstring, "ExcludeFromTriangulation=")
lineToPrev = GrabCodeElement(lcstring, "LineToPrevious=")
featType = GrabCodeElement(lcstring, "FeatureType=")
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
xinCompile.Rows(j).Item("numCode") = NumCode
xinCompile.Rows(j).Item("DTMexclude") = DTMexclude
xinCompile.Rows(j).Item("lineToPrev") = lineToPrev
xinCompile.Rows(j).Item("featType") = featType
ElseIf lcstring.Contains("<Attribute ") Then
LineLayer = GrabCodeElement(lcstring, "Name=")
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
ElseIf lcstring.Contains("<AlphaCode") Then
alphacode = GrabCodeElement(lcstring, "Code=")
If IsDBNull(xinCompile.Rows(j).Item("alphaCode")) Then
fullAlpha = ""
xinCompile.Rows(j).Item("alphaCode") = alphacode
Else
fullAlpha = xinCompile.Rows(j).Item("alphaCode")
xinCompile.Rows(j).Item("alphaCode") = fullAlpha & "," & alphacode
End If
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
Else
wholeTag = wholeTag.Remove(wholeTag.IndexOf(lcstring), wholeTag.IndexOf(">") + 1)
End If
Next
End If
content = content.Remove(0, crntTag.Length)
Else
Exit For
End If
Next
Loop
If you have any recommendations on how to improve any of the above, please let me know.
First off, I've never dealt with FoxPro or Visual FoxPro, so don't expect what I say is going to work perfectly for every scenario. Looking at this MSDN page, it looks like the to perform a simple scatter command in FoxPro you would use something like this:
SCATTER FIELDS LIKE A*,P* EXCEPT PARTNO* TO myArray
The above looks is just getting all fields that start with A* and P* and is excluding items matching PARTNO* from the results. I think this would be best translated to a using LINQ query which could return an Object() array.
Dim testTable As New DataTable
Dim myArray As Object()
myArray = From rowItem In (From row As DataRow In testTable.Rows Select row.ItemArray) _
Where (rowItem.ToString.StartsWith("A") Or rowItem.ToString.StartsWith("P")) _
And Not rowItem.ToString.StartsWith("PARTNO") Select rowItem
If you start getting into the more complicated uses of the scatter command to break up the values into a new object where the object has properties which are the same as the columns in the original table, well the VB equivilent gets much harder because you'll have to make a class that inherits the System.Dynamic.DynamicObject class. So this example from the MSDN page
CREATE TABLE Test FREE ;
(Object C(10), Color C(16), SqFt n(6,2))
SCATTER MEMVAR BLANK
m.Object="Box"
m.Color="Red"
m.SqFt=12.5
APPEND BLANK
GATHER MEMVAR
BROWSE
Turns into a complicated mess in VB. I'm going to provide a very basic example and it is very bare bones but hopefully it'll give you an idea on where to start.
Imports System.Dynamic
Private Class myDynObj : Inherits DynamicObject
Private internalDict As Dictionary(Of String, Object)
Public Sub New()
internalDict = New Dictionary(Of String, Object)
End Sub
Public Sub AddProperty(ByVal PropertyName As String, Optional ByVal Value As Object = Nothing)
addOrSetProperties(New KeyValuePair(Of String, Object)(PropertyName, Value))
End Sub
Public Sub addOrSetProperties(ByVal ParamArray newPropertyValuePairs() As KeyValuePair(Of String, Object))
For Each kvPair As KeyValuePair(Of String, Object) In newPropertyValuePairs.Where(Function(x) Not IsNothing(x.Key))
If internalDict.ContainsKey(kvPair.Key) Then
internalDict.Item(kvPair.Key) = kvPair.Value
Else
internalDict.Add(kvPair.Key, kvPair.Value)
End If
Next
End Sub
Public Overrides Function GetDynamicMemberNames() As IEnumerable(Of String)
Return internalDict.Keys.ToList.Cast(Of String)()
End Function
Public Overrides Function TryGetMember(binder As GetMemberBinder, ByRef result As Object) As Boolean
Return internalDict.TryGetValue(binder.Name, result)
End Function
Public Overrides Function TrySetMember(binder As SetMemberBinder, value As Object) As Boolean
internalDict(binder.Name) = value
Return True
End Function
End Class
And the usage of the above class:
Dim testTable As New DataTable("TheTable")
testTable.Columns.Add("foo")
testTable.Columns.Add("bar")
testTable.Columns.Add("Blargh")
Dim columnNames As New List(Of String)(From column As DataColumn In testTable.Columns Select column.ColumnName)
Dim m As Object = New myDynObj
columnNames.ForEach(Sub(x) DirectCast(m, myDynObj).AddProperty(x))
Console.WriteLine(String.Format("The current properties of the object are as follows: {0}", String.Join(", ", DirectCast(m, myDynObj).GetDynamicMemberNames.Cast(Of String))))
Console.WriteLine()
m.foo = "hoopla" : m.Blargh = 654219 : m.waffles = "I'm New!"
Console.WriteLine("And now the values are:")
DirectCast(m, myDynObj).GetDynamicMemberNames.ToList.ForEach(Sub(x) Console.WriteLine(String.Format("{0}, {1}", x, CallByName(m, x, CallType.Get, Nothing))))
Console.WriteLine()
testTable.Rows.Add(m.foo, m.bar, m.Blargh)
Console.WriteLine("XML result:")
Using sw As New StreamWriter(Console.OpenStandardOutput())
sw.AutoFlush = True
Console.SetOut(sw)
testTable.WriteXml(sw, XmlWriteMode.WriteSchema)
End Using
Console.ReadLine()