How to use a loop through multiple similar textboxes? - asp.net-mvc

Question

So I know this is pretty sloppy, but I have a lot going on for a simple triangulation program (2d) and I'm very new.
The user inputs value in textboxes- "aft1.text,ain1.text,aft2.text,ain2.text,bft1.text,bin1.text,bft2.text,bin1.text." This goes on for as many points that need triangulated. I want to be able to run a loop through these similar textboxes, and run a function on them.
So for each textbox that starts with abft + i and ain + i run the inches function to create a1.
Do the same to create b1.
Then another loop to plot a + i and b + i on the chart per the xcoord/ycoord functions created.
Dim a1 As Double = inches(aft1.Text, ain1.Text)
Dim b1 As Double = inches(bft1.Text, bin1.Text)
If a1 <> 0 And b1 <> 0 Then
Dim targetpoint As Int32
targetpoint = Chart1.Series("Drawing").Points.AddXY((xcoord(a1, b1)), ((ycoord(a1, b1))))
Chart1.Series("Drawing").Points.Item(targetpoint).Label = "1"
End If
Dim a2 As Double = inches(aft2.Text, ain2.Text)
Dim b2 As Double = inches(bft2.Text, bin2.Text)
If a2 <> 0 And b2 <> 0 Then
Dim targetpoint As Int32
targetpoint = Chart1.Series("Drawing").Points.AddXY((xcoord(a2, b2)), ((ycoord(a2, b2))))
Chart1.Series("Drawing").Points.Item(targetpoint).Label = "2"
End If
Dim a3 As Double = inches(aft3.Text, ain3.Text)
Dim b3 As Double = inches(bft3.Text, bin3.Text)
If a3 <> 0 And b3 <> 0 Then
Dim targetpoint As Int32
targetpoint = Chart1.Series("Drawing").Points.AddXY((xcoord(a3, b3)), ((ycoord(a3, b3))))
Chart1.Series("Drawing").Points.Item(targetpoint).Label = "3"
End If

Answer 1

If I understand you correctly, this code can be easily generalized by creating a Sub and calling it with your inches calculation and Label text,:oord are reachable (in scope) Functions:
Triangulate(inches(aft1.Text, ain1.Text), inches(bft1.Text, bin1.Text), 1)
Triangulate(inches(aft2.Text, ain2.Text), inches(bft2.Text, bin2.Text), 2)
Triangulate(inches(aft3.Text, ain3.Text), inches(bft3.Text, bin3.Text), 3)
EDIT-2
Although I have tested the following up to a point, since I do not have your chart properties nor the inches, xcoord and ycoord functions I could not test it completely, so try it out and let me know how it goes.
Sub TriangulateAll()
Try
Dim aft As New SortedList(Of String, TextBox)
Dim ain As New SortedList(Of String, TextBox)
Dim bft As New SortedList(Of String, TextBox)
Dim bin As New SortedList(Of String, TextBox)
For Each ctl As Control In Controls
If TypeOf (ctl) Is TextBox Then
Select Case ctl.Name.Substring(0, 3)
Case "aft"
aft.Add(ctl.Name, ctl)
Case "ain"
ain.Add(ctl.Name, ctl)
Case "bft"
bft.Add(ctl.Name, ctl)
Case "bin"
bin.Add(ctl.Name, ctl)
End Select
End If
Next
Dim a As New List(Of Double)
Dim b As New List(Of Double)
For Each kvp_aft As KeyValuePair(Of String, TextBox) In aft
For Each kvp_ain As KeyValuePair(Of String, TextBox) In ain
a.Add(inches(kvp_aft.Value.Text, kvp_ain.Value.Text))
Next
Next
For Each kvp_bft As KeyValuePair(Of String, TextBox) In bft
For Each kvp_bin As KeyValuePair(Of String, TextBox) In bin
b.Add(inches(kvp_bft.Value.Text, kvp_bin.Value.Text))
Next
Next
For i As Int16 = 0 To aft.Count - 1
Triangulate(a(i), b(i), i.ToString())
Next
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
EDIT
Replace the 3 calls to Triangulate with the following code to completely generalize the Triangulation routine. Note that this routine expects there to be an equal number of each of the TextBox controls: aft, ain, bft, bin. I haven't tested this but it should work.
Dim aft As List(Of TextBox) = Nothing
Dim ain As List(Of TextBox) = Nothing
Dim bft As List(Of TextBox) = Nothing
Dim bin As List(Of TextBox) = Nothing
For Each ctl As Control In Controls
If TypeOf (ctl) Is TextBox Then
Select Case ctl.Name.Substring(0, 2)
Case "aft"
aft.Add(ctl)
Case "ain"
ain.Add(ctl)
Case "bft"
bft.Add(ctl)
Case "bin"
bin.Add(ctl)
End Select
End If
Next
aft.Sort()
ain.Sort()
bft.Sort()
bin.Sort()
For i As Int16 = 0 To aft.Count - 1
Dim a As Double = inches(aft.Item(i).Text, ain.Item(i).Text)
Dim b As Double = inches(bft.Item(i).Text, bin.Item(i).Text)
Triangulate(a, b, i.ToString())
Next
Sub Triangulate(a As Double, b As Double, LabelValue As String)
If a <> 0 And b <> 0 Then
Dim targetpoint As Int32
targetpoint = Chart1.Series("Drawing").Points.AddXY((xcoord(a, b)), ((ycoord(a, b))))
Chart1.Series("Drawing").Points.Item(targetpoint).Label = LabelValue
End If
End Sub