Asp.Net

How to handle ""Maximum request length exceeded" exception

Sglima — Tue, 20 Sep 2011 11:36:54 GMT

In global.asax:

protected void Application_BeginRequest(Object sender, EventArgs e)
{
	HttpRuntimeSection runTime = (HttpRuntimeSection)WebConfigurationManager.GetSection("system.web/httpRuntime");
	//Approx 100 Kb(for page content) size has been deducted because the maxRequestLength proprty is the page size, not only the file upload size
	int maxRequestLength = (runTime.MaxRequestLength - 100) * 1024;
 
	//This code is used to check the request length of the page and if the request length is greater than 
	//MaxRequestLength then retrun to the same page with extra query string value action=exception

	HttpContext context = ((HttpApplication)sender).Context;
	if(context.Request.ContentLength > maxRequestLength)
	{
		IServiceProvider provider = (IServiceProvider)context;
		HttpWorkerRequest workerRequest = (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
		// Check if body contains data
		if(workerRequest.HasEntityBody())
		{
			// get the total body length
			int requestLength = workerRequest.GetTotalEntityBodyLength();
			// Get the initial bytes loaded
			int initialBytes = 0;
			if(workerRequest.GetPreloadedEntityBody() != null)
				initialBytes = workerRequest.GetPreloadedEntityBody().Length;
			if(!workerRequest.IsEntireEntityBodyIsPreloaded())
			{
				byte[] buffer = new byte[512000];
				// Set the received bytes to initial bytes before start reading
				int receivedBytes = initialBytes;
				while(requestLength - receivedBytes >= initialBytes)
				{
					// Read another set of bytes
					initialBytes = workerRequest.ReadEntityBody(buffer, buffer.Length);
					// Update the received bytes
					receivedBytes += initialBytes;
				}
				initialBytes = workerRequest.ReadEntityBody(buffer, requestLength - receivedBytes);
			}
		}
		// Redirect the user to the same page with querystring action=exception. 
		context.Response.Redirect("~/Erros/FicheiroGrande.aspx");
	}
}

Source

How to execute a javascript function every time an updatepanel executes an async postback

Sglima — Tue, 20 Sep 2011 09:57:32 GMT

Sys.WebForms.PageRequestManager.getInstance().add_endRequest(refresh);

function refresh() { //Your code here; }

</script>

Source

How to: Invoke a method by name

Sglima — Mon, 31 May 2010 13:41:50 GMT

Type myType = typeof(MyClass);

string methodName = "methodNameAsString";

MethodInfo myTypeGetMethod = myType.GetMethod(methodName);

MyClass obj = new MyClass();

object[] parms = { 123, "string test"};

myTypeGetMethod.Invoke(obj, args);

How to: Change Master Page at runtine

Sglima — Wed, 03 Mar 2010 11:39:49 GMT

        protected override void OnPreInit(EventArgs e)
        {
            Page.MasterPageFile = "~/LinkToMasterPage";
            base.OnInit(e);
        }

Enjoy :)

How to use an Aspx as a proxy for a PDF file

Sglima — Fri, 05 Feb 2010 18:25:55 GMT

Response.Clear();
Response.ContentType = "application/pdf";
Response.AddHeader("Content-Disposition", "attachment;filename=\"FileName.pdf\"");

Response.BinaryWrite(yourPdfAsByteArray);

Response.Flush();

Response.End();     SourceEnjoy :)

Hidding auto generated columns in GridView

Sglima — Thu, 29 Oct 2009 14:23:58 GMT

Hello,

If you are reading this you probably have already realized that it is not possible to hide a column that was auto-generated using myGridView.Columns[index].Visible=false;
To achieve this you must:
1 - set the OnRowCreated to execute a function, something like OnRowCreated="gridRowCreated"
2 - Create your function as such:

protected void gridRowCreated(object sender, GridViewRowEventArgs e)
        {
            e.Row.Cells[yourIndexHere].Visible = false;
        }

Hope this helps ;)

Prevent Double Post

Sglima — Wed, 19 Aug 2009 17:26:09 GMT

A few days ago I got an error report to fix. Some web application that I now maintain was inserting duplicate records.

After a quick look it became obvious that the users where double clicking the submit button and that made the page post twice and so a duplicate record would appear.

A quick fix dor this problem using javascript:

<script language="javascript" type="text/javascript">
        var haveSubmitted=false;
        function FirstSubmitOnly() {
            if (haveSubmitted)
                return false;

            haveSubmitted = true;
            return true;
        }
    </script>

And at the form tag just invoke the function <form id="form1" runat="server" onsubmit="return FirstSubmitOnly();">

Enjoy :)

Keep Scroll on Postback

Sglima — Fri, 05 Jun 2009 16:30:31 GMT

I think at some point everybody had this problem... A big form with some control that forces a postback. If you have scrolled down, the page scroll will be placed at the top.

To force the aspx to keep the scroll, just place the following instrucion on the <pages> tag of your web config.

<pages maintainScrollPositionOnPostBack="true">

Enjoy :)

Asp.Net Auto refresh

Sglima — Mon, 04 May 2009 17:05:39 GMT

Simple how to refresh page every 60 seconds

<meta http-equiv="refresh" content="60">

Export Aspx to Excel

Sglima — Fri, 17 Apr 2009 22:49:31 GMT

Just a simple snippet to show how an aspx can be exported to Excel

Response.ClearContent();
Response.Buffer = true;
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("content-disposition", "attachment; filename=" + "teste" + ".xls;charset=iso-8859-1");

StreamWriter sw = new StreamWriter(Response.OutputStream, System.Text.Encoding.GetEncoding("iso-8859-1"));
HtmlTextWriter htmlTextWriter = new HtmlTextWriter(sw);
this.RenderControl(htmlTextWriter);

Response.End();