Question

I have a list of specific class.
In this list , a position class is included.
And that position class includes X and Y coordinates.
I have Current Coordinates and the coordinates in list .
I want to calculate the distance for each item in List and find which item has minimal distance.
Here is my code :

  For Each item As ITEMX In xHandle.ItemList

        Dim CurrX As Integer = txt_TrainX.Text
        Dim CurrY As Integer = txt_TrainY.Text
        Dim NextX As Integer = item.Position.x
        Dim NextY As Integer = item.Position.y

        Dim distance As Integer = DistanceBetween(CurrX, CurrY, NextX, NextY)


    Next

so distance is the distance between my coordinates and the item.
I calculate it for each item in list but how do i find the minimal one ?

Thank you.

Answer 1

Create a variable for the minimal value, and check it against each value in the loop.

You should parse the text from the controls outside the loop, it’s a waste to do that over and over again inside the loop. You should also turn on strict mode so that you don’t do implicit conversions that shouldn’t be implicit.

Dim minimal As Nullable(Of Integer) = Nothing

Dim CurrX As Integer = Int32.Parse(txt_TrainX.Text)
Dim CurrY As Integer = Int32.Parse(txt_TrainY.Text)

For Each item As ITEMX In xHandle.ItemList

  Dim NextX As Integer = item.Position.x
  Dim NextY As Integer = item.Position.y

  Dim distance As Integer = DistanceBetween(CurrX, CurrY, NextX, NextY)

  If Not minimal.HasValue or distance < minimal.Value Then
    minimal.Value = distance
  End If

Next