I'm Try to convert Black & White image to color image using matrixs of RGB colors

Here is my simple code but it give me nothing altho the RGB values are in the program:
'-------------------------------------Picture color change--------------------
        Dim bm As Bitmap = New Bitmap("C:\trash\Babymono100.bmp")

        Dim x

        Dim y

        For y = 0 To bm.Height - 1

            For x = 0 To bm.Width - 1

                Dim c As Color = bm.GetPixel(x, y)

                TextBox1.Text = c.R

                For i = 1 To 10000


                    If c.R = DataGridViewGray.Rows(i).Cells(1).Value Then
                        bm.SetPixel(x, y, Color.FromArgb(DataGridViewRed.Rows(i).Cells(1).Value, DataGridViewGreen.Rows(i).Cells(1).Value, DataGridViewBlue.Rows(i).Cells(1).Value))

                        Exit For
                    End If

                Next
            Next
        Next
        PictureBox1.Image = bm