I can't plot the chart by array

I getpixel from my picturebox2 and save pixel data at array xx , yy and then i want to plot the chart from array xx and yy

I don't have error code but when run ,it's going to be

"An unhandled exception of type 'System.InvalidOperationException' occurred in mscorlib.dll"



"Additional information: Enumeration already finished"

My englise is not good. I am sorry for that. but I hope you will understand me.

Help me please :)

Private Sub Runbotton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Runbotton.Click

        Dim MH As Integer
        Dim MW As Integer
        MH = PictureBox2.Height
        MW = PictureBox2.Width
        ProgressBar1.Minimum = 0
        ProgressBar1.Maximum = MW

        Dim xx(MW) As Integer
        Dim yy(MH) As Integer
        Dim co As Integer = 0

        For co = 0 To MW
            xx(co) = 0
        Next

        For co = 0 To MH
            yy(co) = 0
        Next

        Dim img As Bitmap = New Bitmap(PictureBox2.Image)
        Dim c As Color

        Dim i As Integer

        For i = 0 To MW
            Dim j As Integer
            For j = 0 To MH
                c = img.GetPixel(i, j)
                Dim r As Integer = 0
                r = Convert.ToInt32(c.R)
                Dim g As Integer = 0
                g = Convert.ToInt32(c.G)
                Dim b As Integer = 0
                b = Convert.ToInt32(c.B)
                Dim ans As Integer = r + g + b
                If (ans > 50) Then
                    yy(j) = yy(j) + 1
                End If
                xx(i) = xx(i) + i
            Next
            ProgressBar1.Value = i
        Next
        MessageBox.Show("Successfully")

        Dim x() As Integer = {1, 2, 3, 4, 5}
        

        Chart1.Series(0).Points.DataBindXY(xx, yy)
       
    End Sub