Zero value problem in datagridview

[sparrow1]

I've gat a datagridview bound to a datatable and I want to show Max and Min values.
The code I have is working and showing the proper decimal Max and Min value in a textbox.
The problem I have is when there is a "0" value in the column then de value is always "0".
That is not what I want.
How can I avoid this problem?

  
Dim cells = From r As DataGridViewRow In DataGridView1.Rows.Cast(Of DataGridViewRow)()
            Where Not r.IsNewRow
            Select CDec(r.Cells(3).Value)

Dim min As Decimal = cells.Min
Dim minval As New cell With {.columnIndex = 3, .rowIndex = Array.IndexOf(cells.ToArray, min)}

Dim max As Decimal = cells.Max
Dim maxval As New cell With {.columnIndex = 3, .rowIndex = Array.IndexOf(cells.ToArray, max)}

TextBox1.Text = max & " / " & min

[jmcilhinney]

That is not what I want.

So what do you want? Perhaps you could say it explicitly. Are you suggesting that negative values are being ignored when they shouldn't be or that zero values aren't being ignored when they should be? If it's the latter then you would need to add a filter to exclude zero values. It's the Where clause that does the filtering in a LINQ query and you already have one of those. You just need to add an appropriate condition to it.

[sparrow1]

What I want is that a negative (Min) or positive (Max) value will be displayed.
With that information can I do other calculations and show the results in a graphic.

I found a way to exclude zero values, but still showing -12,00 or 12,00.
It maybe not the best way, but it works.

 Dim Max As Decimal = 0
        For Each rws As DataGridViewRow In DataGridView1.Rows
            If rws.Cells(3).Value Is Nothing Or rws.Cells(3).Value = 0 Then

            Else
                If Max < rws.Cells(3).Value Then Max = rws.Cells(3).Value
            End If
        Next

        Dim Min As Decimal = Max
        For Each rws As DataGridViewRow In DataGridView1.Rows
            If rws.Cells(3).Value Is Nothing Or rws.Cells(3).Value = 0 Then

            Else
                If Min > rws.Cells(3).Value Then Min = rws.Cells(3).Value
            End If
        Next

[ChrisE]

I put your Min/Max in Function's

Option Strict On

Public Class Form1
    Private dt As New DataTable()

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        dt.Columns.AddRange(New DataColumn(3) {New DataColumn("ProductId", GetType(Integer)), _
                                            New DataColumn("P1", GetType(String)), _
                                            New DataColumn("P2", GetType(Decimal)), _
                                            New DataColumn("P3", GetType(Decimal))})

        dt.Rows.Add(1, "Apple", 45.12, 4)
        dt.Rows.Add(2, "Orange", 32, 8.5)
        dt.Rows.Add(3, "Cherry", 0, 5)
        dt.Rows.Add(4, "Plum", -3, 0)
        dt.Rows.Add(5, "Mango", 199.12, 4)

        DataGridView1.DataSource = dt

        Dim mMax As Decimal = GetMaxValue(dt, 2)
        Dim mMin As Decimal = GetMinValue(dt, 2)

        TextBox1.Text = mMax & " / " & mMin
    End Sub

    Public Function GetMaxValue(ByVal TB As DataTable, _
                               ByVal cColumn As Integer) As Decimal
        Dim SumVal As Decimal = 0
        For Each Rw As DataRow In TB.Rows
            SumVal = CDec(TB.AsEnumerable().Max(Function(x) x(cColumn)))
        Next
        Return SumVal
    End Function

    Public Function GetMinValue(ByVal TB As DataTable, _
                                ByVal cColumn As Integer) As Decimal
        Dim SumVal As Decimal = 0
        For Each Rw As DataRow In TB.Rows
            SumVal = CDec(TB.AsEnumerable().Min(Function(x) x(cColumn)))
        Next
        Return SumVal
    End Function
End Class