ASP.NET

Public Function ResizeCropImage(ByVal sFilepath As String, ByVal ext As String) As Integer
   ' sFilepath = relative path to file, including it's name;  ext = file extension
   ' this file has already been saved from File Upload control via it's usual SaveAs method
   Try
      Dim FullSizeImage As Image
      FullSizeImage = Image.FromFile(HttpContext.Current.Server.MapPath(sFilepath))

      If (FullSizeImage.Height < 200) Or (FullSizeImage.Width < 200) Then
         FullSizeImage.Dispose()
         ' image is too small
         System.IO.File.Delete(HttpContext.Current.Server.MapPath(sFilepath))
         Return 0
      End If

      Dim imf As System.Drawing.Imaging.ImageFormat
      Select Case ext
         Case ".gif"
            imf = System.Drawing.Imaging.ImageFormat.Gif
         Case ".png"
            imf = System.Drawing.Imaging.ImageFormat.Png
         Case Else '".jpg", ".jpeg"
            imf = System.Drawing.Imaging.ImageFormat.Jpeg
      End Select


      Dim tmp As Bitmap
      Dim gX As System.Drawing.Graphics

      Dim bTidy As Boolean = True

      If (FullSizeImage.Height = 200) And (FullSizeImage.Width = 200) Then
         'nothing to do
         bTidy = False
      Else
         ' resize/crop to 200 x 200
         Select Case FullSizeImage.Height / FullSizeImage.Width
            Case Is < 1 'landscape image
               Dim x1 As Integer
               tmp = New Bitmap(200, 200)
               tmp.SetResolution(FullSizeImage.HorizontalResolution, FullSizeImage.VerticalResolution)
               x1 = CInt((FullSizeImage.Width / 2) - (FullSizeImage.Height / 2))
               gX = System.Drawing.Graphics.FromImage(tmp)
               gX.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic
               gX.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality
               gX.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality
               gX.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality
               gX.DrawImage(FullSizeImage, New Rectangle(0, 0, 200, 200), New Rectangle(x1, 0, FullSizeImage.Height, FullSizeImage.Height), GraphicsUnit.Pixel)
            Case Is > 1 ' portrait image
               ' similar code for portrait images - omitted here to save space/bandwidth
            Case Else   ' square image,
               ' similar code for square images - omitted here to save space/bandwidth
         End Select
         ' save with amended filename (not to conflict with original)
         tmp.Save(HttpContext.Current.Server.MapPath(sFilepath.Replace(ext, "_c" & ext)), imf)
         tmp.Dispose()
         gX.Dispose()

      End If

      ' clean up
      FullSizeImage.Dispose()

      If bTidy Then
         ' delete original
         System.IO.File.SetAttributes(HttpContext.Current.Server.MapPath(sFilepath), FileAttributes.Normal)
         System.IO.File.Delete(HttpContext.Current.Server.MapPath(sFilepath))
         ' rename just saved amended file with filename of original
         System.IO.File.Move(HttpContext.Current.Server.MapPath(sFilepath.Replace(ext, "_c" & ext)), HttpContext.Current.Server.MapPath(sFilepath))
      End If

      Return 1
   Catch ex As Exception
      ' write error to log file
      writeLog("funcs/ResizeCropImage", ex.Message, Err.ToString)
      Return -1
   End Try
End Function

x1 = CInt((FullSizeImage.Width / 2) - (FullSizeImage.Height / 2))
y1=-x1
if x1<0 then x1=0
if y1<0 then y1=0

Xandip wrote:

NB: I'm a beginner

public static class SequentialNumbers
  {
    private static Object obj = new Object();
    private static UInt16 lastNumber = UInt16.MinValue;

    public static UInt16 GetNext()
    {
      lock (obj)
      {
        return ++lastNumber;
      }
    }
  }

/* Global.asax */
void Application_Start(object sender, EventArgs e)
{
    int id;
    int.TryParse(System.IO.File.ReadAllText(Server.MapPath("~/nextid.txt")), out id);
    Application["ID"] = id;
}

void Application_End(object sender, EventArgs e)
{
    // Delete the old file
    System.IO.File.Delete(Server.MapPath("~/nextid.txt"));
    // Write out the new one
    System.IO.File.WriteAllLines(Server.MapPath("~/nextid.txt"), new string[] { Application["ID"].ToString() });
}

/* Some publicly accessible class */
public int GetNextID()
{
    // Increase the id
    Application["ID"] = Convert.ToInt32(Application["ID"]) + 1;
    return (int)Application["ID"];
}

objDA.Fill(ds);
            DataColumn c1 = ds.Tables["category"].Columns["categoryID"];
            DataColumn c2 = ds.Tables["Item"].Columns["catID"];
            dRel = new DataRelation("categoryItem", c1, c2);
            ds.Relations.Add(dRel);
            Repeater1.DataSource = ds;
            Repeater1.DataBind();

 Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 1222:            objDA.Fill(ds);
Line 1223:
Line 1224:              DataColumn c1 = ds.Tables["category"].Columns["categoryID"];
Line 1225:           DataColumn c2 = ds.Tables["Item"].Columns["catID"];
Line 1226:            dRel = new DataRelation("categoryItem", c1, c2);

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 1222:            objDA.Fill(ds);
Line 1223:
Line 1224:            DataColumn c1 = ds.Tables["category"].Columns["ID"];
Line 1225:            DataColumn c2 = ds.Tables["item"].Columns["catID"];
Line 1226:            dRel = new DataRelation("categoryItem", c1, c2);

void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
       {
           RepeaterItem item = e.Item;
           if ((item.ItemType == ListItemType.Item) ||
               (item.ItemType == ListItemType.AlternatingItem))
           {

               Repeater2 = (Repeater)e.Item.FindControl("Repeater2");
               DataRowView drv = (DataRowView)item.DataItem;
               Repeater2.DataSource = drv.CreateChildView("categoryItem");
               Repeater2.DataBind();
           }
       }

objDA.Fill(ds);
            DataColumn c1 = ds.Tables["category"].Columns["ID"];
            DataColumn c2 = ds.Tables["Item"].Columns["catID"];
            dRel = new DataRelation("categoryItem", c1, c2);
            ds.Relations.Add(dRel);
            Repeater1.DataSource = ds;
            Repeater1.DataBind();