Concatenate Variable Names in VB

Question

I have a large window with a little under 200 controls/variables to worry about. Many of them are similar, so I am wondering if instead of repeatedly calling each one individually I can concatenate their names.

I'll make an example:

I have 5 pieces of data that I'm worried about: Red, Orange, Yellow, Green, Blue.

Each one of these will have a label that needs to be made visible, a textbox that needs to be made visible, and a string that contains the text in the textbox:

lblRed.Visible = True
txtRed.Visible = True
strRed = txtRed.Text

Instead of listing this for every one of those 5 pieces of data, is there a way that I could make some sort of array to loop through that could concatenate these variable names?

Dim list As New List(Of String)(New String() {"Red", "Orange", "Yellow", "Green", "Blue"})
Dim i As Integer = 0
Do while i < list.count
  lbl + list(i) + .Visible = True
  txt + list(i) + .Visible = True
  str + list(i) = txt + list(i) + .Text
  i = i+1
Loop

I know that the above code doesn't work, but I wanted to give you the basic idea of what I wanted to do. Does this look feasible?

score 2 · Accepted Answer · answered Jul 10 '13 at 18:40

http://msdn.microsoft.com/en-us/library/7e4daa9c(v=vs.71).aspx

Using the controls collection:

    Dim i As Integer
    i = 1
    Me.Controls("Textbox" & i).Text = "TEST"

so

Me.controls("lbl" & list(i)).Visible = true

Keep in mind that when concatenating items, '+' will work on strings and not integers. You might want to always use '&' when concatenating

score 0 · Answer 2 · answered Jul 10 '13 at 19:02

Another way is to use a select-case block for each type of control. Something like this:

Private Sub EnableControls()
    For Each c As Control In Me.Controls
        Select Case c.GetType
            Case GetType(TextBox)
                c.Visible = True
                Select Case c.Name.Substring(3)
                    Case "Red"
                        strRed = c.Text
                    Case "Orange"
                        strOrange = c.Text
                    Case "Yellow"
                        'and so on
                End Select
            Case GetType(Label)
                c.Visible = True
        End Select
    Next
End Sub

score 0 · Answer 3 · answered Jul 10 '13 at 19:30

Check out the information here:

http://msdn.microsoft.com/en-us/library/axt1ctd9.aspx

I'm sure someone may find something slightly more eloquent than this, but this should achieve your desired result. You'll need the below import:

Imports System.Reflection

If you use properties to access your variables, you can use reflection to grab them by name:

'Define these with getters/setters/private vars
Private Property strRed as String
Private Property strOrange as String 
Private Property strYellow as String 
Private Property strGreen as String 
Private Property strBlue as String 

For each color as String in list
    If Me.Controls.Count > 1 Then
         'Should really check for existence here, but it's just an example.
         Me.Controls("lbl" & color).Visible = True
         Dim tbx as TextBox = Me.Controls("txt" & color)
         tbx.Visible = True
         Dim propInfo as PropertyInfo = Me.GetType.GetProperty("str" & color)
         propInfo.SetValue(Me, tbx.Text, Nothing)
     End If
Next

Concatenate Variable Names in VB

3 Answers3

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