Export chart to MemoryStream

[Ramunas]

HiI try to export chart image to MemoryStream object, store it to cache and show image via HTTP handler from cache. I don't know what is wrong with my code and/or chart settings but sometimes I get chart image with a missing bottom part at height 10-20 px. Moreover, if I export chart in JPEG format then both IE7 and FF shows image as it is (even with "missing" bottom part), but if I use PNG format while exporting then IE7 does not show image at all.Here is my code:chart.aspx.cs

---

public void RenderChart()

{

Chart chart = new Chart();

chart.DataSource = GetFormattedDataSource(); // just a simple datatable with data

chart.DataBind();

string chartID = Guid.NewGuid().ToString(); // used to store chart's image in cache

MemoryStream ms = new MemoryStream();

chart.ImgHeight = 600;

chart.ImgWidth = 1300;

chart.SerLegBox = true;

chart.DataType[0] = SoftwareFX.ChartFX.DataType.Label;

// I setup series here (Gallery, Pallete, etc.)

chart.RecalcScale(); //just in case

chart.Grid = ChartGrid.Horz;

chart.AxisX.LabelAngle = -90;

chart.Series[0].PointLabels = true;

chart.AxisY.LabelsFormat.CustomFormat = "#,###";

chart.Export(FileFormat.Jpeg, ms);

ms.Position = 0; // have read in forums that could be usefull

//store byte[] array from MemoryStream to cache

Cache.Add(chartID, ms.ToArray(), null, System.Web.Caching.Cache.NoAbsoluteExpiration, TimeSpan.FromMinutes(5), System.Web.Caching.CacheItemPriority.NotRemovable, null);

ms.Dispose();

// set image control's ImageUrl property to a handler to return image from cache

this.imageChart.ImageUrl = "~/Charts/GetChart.ashx?ChartID=" + chartID;

}GetChart.ashx

---

private const string QUERY_STRING_KEY = "ChartID";

public void ProcessRequest(HttpContext context)

{

if (string.IsNullOrEmpty(context.Request.QueryString[QUERY_STRING_KEY]))

{

return;

}

string chartID = context.Request.QueryString[QUERY_STRING_KEY];

 

byte[] chart;

chart = (byte[])context.Cache.Get(chartID);

 

context.Response.ClearHeaders();

context.Response.ClearContent();

 

context.Response.ContentType = "image/jpeg";

context.Response.Buffer = true;

context.Response.StatusCode = 200;

context.Response.OutputStream.Write(chart, 0, chart.GetUpperBound(0));

context.Response.Flush();

context.Response.End();

}I just don't know if/what I am doing wrong that I get (i suspect) corrupted images.Thanks in advanceRamunas

[Ramunas]

Never mind. I found a bug.In case someone else has the same problem....I miss-interpreted the context.Response.OutputStream.Write() method. Last argument is not last item of array but count.So in GetChart.ashx handler instead of callingcontext.Response.OutputStream.Write(chart, 0, chart.GetUpperBound(0));I called context.Response.OutputStream.Write(chart, 0, chart.GetUpperBound(0) + 1);and all image formats (jpeg, png) are shown on page correctly.

[Young]

Can you let me know how your code in chart.aspx, please? How RenderChart() attached to it? Thanks.