Trucos de ASP.NET Generar gráficos dinámicamente

Imports System.Drawing

Imports System.Drawing.Imaging

Public Class graph

Inherits System.Web.UI.Page

#Region " Código generado por el Diseñador de Web Forms "

'El Diseñador de Web Forms requiere esta llamada.

<;System.Diagnostics.DebuggerStepThrough()>; Private Sub InitializeComponent()

End Sub

'NOTA: el Diseñador de Web Forms necesita la siguiente declaración del marcador de posición.

'No se debe eliminar o mover.

Private designerPlaceholderDeclaration As System.Object

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init

'CODEGEN: el Diseñador de Web Forms requiere esta llamada de método

'No la modifique con el editor de código.

InitializeComponent()

End Sub

#End Region

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim objBitmap As New Bitmap(700, 200)

Dim objGraphic As Graphics = Graphics.FromImage(objBitmap)

Dim orange As New SolidBrush(Color.Orange)

Dim whiteBrush As New SolidBrush(Color.White)

Dim lineColor As New Pen(Color.Blue, 2)

objGraphic.FillRectangle(whiteBrush, 0, 0, 700, 200)

objGraphic.DrawLine(lineColor, New Point(0, 190), New Point(700, 190))

objGraphic.DrawLine(lineColor, New Point(5, 5), New Point(5, 195))

Dim l_arr As New ArrayList

'inserción en el array de valores para el ejemplo

l_arr.Add("800")

l_arr.Add("01/01/07")

l_arr.Add("500")

l_arr.Add("02/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

l_arr.Add("200")

l_arr.Add("03/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

l_arr.Add("1300")

l_arr.Add("03/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

l_arr.Add("1000")

l_arr.Add("03/01/07")

Dim i As Int32 = 0

Dim pos As Int32 = 0

Dim PointValue As New PointF(-30, 0)

Dim PointDate As New PointF(-30, 190)

Dim objFont As New Font("Verdana", 10)

Dim FontDate As New Font("Verdana", 7)

Dim wb2 As New SolidBrush(Color.Black)

Dim x As Int32 = -50

Dim maxValue As Int32 = 0

'calculo del máximo valor de la gráfica

i = 0

While i <; l_arr.Count

If l_arr(i) >; maxValue Then

maxValue = l_arr(i)

End If

i += 2

End While

'creación de todos los rectángulos de la gráfica

i = 0

While i <; l_arr.Count

x += 70

Dim aux As Int32

aux = (l_arr(i) * 189) / (maxValue + 200)

objGraphic.FillRectangle(orange, x, 189 - aux, 40, aux)

PointValue.X = x

PointDate.X = x - 10

objGraphic.DrawString(l_arr(i).ToString, objFont, wb2, PointValue)

objGraphic.DrawString(l_arr(i + 1).ToString, FontDate, wb2, PointDate)

i += 2

End While

Response.ContentType = "image/gif"

objBitmap.Save(Response.OutputStream, ImageFormat.Gif)

End Sub