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System.OutOfMemoryException when writing a csv file K.Safvi3-Nov-09 2:40 K.Safvi 3-Nov-09 2:40  Dear All, In download data module of my application(with asp.net2.0/sqlserver2005)one of the function is returning a datareader object having 7 hundererd thousands plus record. It returns the datareader without an exception but when i am iterating through the datareader to take its values to a string bulider type varible to write a csv file, it throws an 'System.OutOfMemoryException' due to huge records. I can not filter the record as it is required to write a csv file of the whole data. how can i avoide this error and improve the efficency of the system so that it takes less resources. The compilation debug is set to false. Also when there a few hundered thousand records the download is working ok. Thanks in advance for the help form any esteemed member. Thanks, Safvi Re: System.OutOfMemoryException when writing a csv file- here is my code K.Safvi3-Nov-09 2:47 K.Safvi 3-Nov-09 2:47  public static string WriteCSVFilebyDataReader(SqlDataReader SqlDataReaderObject) { StringBuilder strResult = new StringBuilder(); try { for (int i = 0; i < SqlDataReaderObject.FieldCount; i++) { strResult.Append("\" " + SqlDataReaderObject.GetName(i) + " \","); } strResult.Append("\n"); if (SqlDataReaderObject.HasRows) { while (SqlDataReaderObject.Read()) { for (int j = 0; j < SqlDataReaderObject.FieldCount; j++) { strResult.Append("\"" +SqlDataReaderObject.GetValue(j).ToString() + "\","); } strResult.Append("\n"); //SqlDataReaderObject.NextResult(); } } } catch (Exception ex) { throw ex; } return strResult.ToString(); } Re: System.OutOfMemoryException when writing a csv file Shameel3-Nov-09 2:55 Shameel 3-Nov-09 2:55  When you use a datareader, data is not fetched from the database until you use the Read() method to read the next row, therefore you may not receive an error when you open the datareader. The problem seems to be with StringBuilder. You can split the result into batches of say 10000 rows and then write them. For example, open the csv file write 10000 rows, close it, then append the next 10000 rows and so on. You could do this using a loop counter. Each batch would use a new StringBuilder instance to write to the csv file. how can i write , update and delete in xml file pramodgorityala3-Nov-09 2:20 pramodgorityala 3-Nov-09 2:20  Hi everyone, Please read the xml file below. Thanks. (1). Given id="100" and quantity=2. id="100" exists in the xml file. Then update quantity (i.e., 1+2 = 3) in the xml file. (2). Given id="300" and quantity=1. id="300" does not exist in the xml file, then insert this new record (i.e., &lt;item id="300"&gt;&lt;itemName&gt;Bike&lt;/itemName&gt;&lt;price&gt;150.99&lt;/price&gt;&lt;quantity&gt;1&lt;/quantity&gt;&lt;/item&gt;) into the xml file. (3). Given id="200". id="200" exist, then delete this record (&lt;item id="200"&gt;&lt;itemName&gt;Car&lt;/itemName&gt;&lt;price&gt;99.99&lt;/price&gt;&lt;quantity&gt;1&lt;/quantity&gt;&lt;/item&gt;) <products> <item id="100"> <itemName>Car</itemName> <price>99.99</price> <quantity>1<quantity> </item> <item id="200"> <itemName>Car</itemName&gt> <price>99.99</price> <quantity>1</quantity> </item> </products> iam writing code in vb.net but i cont please help me, Can I have some sample code Thanks, modified on Tuesday, November 3, 2009 9:26 AM Re: how can i write , update and delete in xml file Abhishek Sur3-Nov-09 3:51 Abhishek Sur 3-Nov-09 3:51  Why dont you use XDocument (LINQ to XML) to do this. This might be a good to start : Linq to XML[^] You can also see this : http://www.codeguru.com/csharp/csharp/cs_linq/article.php/c13715/[^] Cheers. Abhishek Sur Don't forget to click "Good Answer" if you like this Solution. My Latest Articles--> Microsoft Bing MAP using Javascript CLR objects in SQL Server 2005 Uncommon C# Keywords/xml> Re: how can i write , update and delete in xml file Mesut KOSUCU3-Nov-09 5:41 Mesut KOSUCU 3-Nov-09 5:41  You might be interested in this article.. http://www.devx.com/dotnet/Article/31838/0/page/3[^] Re: how can i write , update and delete in xml file Oakman3-Nov-09 5:52 Oakman 3-Nov-09 5:52  pramodgorityala wrote: Can I have some sample code Let's save you some time and trouble. Give us the email address of your teacher and we'll send the solution direct to him. Jon Rob Graham wrote: 100% subsidies are very popular among the 50% of the population that pays no income tax... Soap Box 1.0: the first, the original, reborn troll-less Re: how can i write , update and delete in xml file Christian Graus3-Nov-09 8:44 Christian Graus 3-Nov-09 8:44  Welcome to the ASP.NET forum.... Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks. Insert multiple records Member 42602703-Nov-09 1:34 Member 4260270 3-Nov-09 1:34  Hi all, I have an asp.net page ,contains 3 textboxes ,1 dropdownlis,1 button. I have written the code for inserting data to the database inn the button click event.Its working properly,and cleared the textbox datas. But after inserting the datas, I clear the texts in the textboxes and set visible=false. Afetr this I tried to refresh the page,the above textbox values are again inserted into the database. If somebody knows about this ,pls help me. Thanks and Regards Denny Re: Insert multiple records m@dhu3-Nov-09 1:47 m@dhu 3-Nov-09 1:47  TextBox.Text=""; to clear data in text box... Re: Insert multiple records Member 42602703-Nov-09 1:51 Member 4260270 3-Nov-09 1:51  I have done already but still prob Re: Insert multiple records N a v a n e e t h3-Nov-09 1:52 N a v a n e e t h 3-Nov-09 1:52  The postback data won't be cleared and when you refresh, it will be resend. To work around this, consider redirecting the page after insert. // do insert Response.Redirect("success.aspx") Best wishes, Navaneeth Re: Insert multiple records Member 42602703-Nov-09 1:55 Member 4260270 3-Nov-09 1:55  but sir,i have a grid in that page and i want to show the values in the grid Re: Insert multiple records Shameel3-Nov-09 2:05 Shameel 3-Nov-09 2:05  This is the way ASP.NET postback works. When you refresh, your browser submits the same page with the same postback information. The only way you can avoid it is by redirecting it to a different page. Re: Insert multiple records Member 42602703-Nov-09 2:25 Member 4260270 3-Nov-09 2:25  Thanks for you help Re: Insert multiple records Oakman3-Nov-09 5:57 Oakman 3-Nov-09 5:57  What do you mean when you say 'refresh the page?' How, exactly, are you doing that? Ignore any answers that suggest that viewstate will not contain the latest value inserted into a textbox, including string.empty. Without seeing rhe code it's hard to know, but it sounds like you may be rebinding those textboxes to your datastore. Jon Rob Graham wrote: 100% subsidies are very popular among the 50% of the population that pays no income tax... Soap Box 1.0: the first, the original, reborn troll-less Persist a dataset across postbacks tonymathewt3-Nov-09 1:22 tonymathewt 3-Nov-09 1:22  What is the best approach to persist a dataset across postbacks so that users could manipulate the data in it and could be saved(to the database) at last. Re: Persist a dataset across postbacks N a v a n e e t h3-Nov-09 1:54 N a v a n e e t h 3-Nov-09 1:54  You can put it in ViewState. Best wishes, Navaneeth Re: Persist a dataset across postbacks tonymathewt5-Nov-09 1:29 tonymathewt 5-Nov-09 1:29  I am using ViewState now but I notice the page is slower during reloads Re: Persist a dataset across postbacks Shameel3-Nov-09 2:09 Shameel 3-Nov-09 2:09  You can use viewstate, but if the size of the dataset is very large, it will bloat the request and response size and can probably kill your app. Use a DataTable object and persist it in session. You can also try serializing the object to a database and save the key in viewstate. Each approach has its own advantages and disadvantages. You should try to find out what works best for you. Re: Persist a dataset across postbacks tonymathewt5-Nov-09 0:37 tonymathewt 5-Nov-09 0:37  Hello Shameel How about persisting the DataSet(as I have more than one DataTable) in a Session variable and clearing it(using Session.Remove()) while the user navigates away from the page? Re: Persist a dataset across postbacks Abhishek Sur3-Nov-09 3:55 Abhishek Sur 3-Nov-09 3:55  The best way is not to Persist the dataset ever. Just save the changes during postbacks and show the most recent data. Remember, the user might go next page on next date. Or might be there is a session timeout. If you store everything in context, that means errors might loose everything. Abhishek Sur Don't forget to click "Good Answer" if you like this Solution. My Latest Articles--> Microsoft Bing MAP using Javascript CLR objects in SQL Server 2005 Uncommon C# Keywords/xml> Re: Persist a dataset across postbacks tonymathewt5-Nov-09 18:01 tonymathewt 5-Nov-09 18:01  Thank you Abhishek You re right. But here I am faced with a situation to reduce database hits rather than concurrency. I am having multiple tables so using DataSet. When I stored it in a ViewState variable I notice the page loading slower. Re: Persist a dataset across postbacks Abhishek Sur5-Nov-09 20:35 Abhishek Sur 5-Nov-09 20:35  Dont load such a huge data in ViewState. When you request for something, you send viewstate with it(even if it is an AJAX request). After receiving the viewstate it decrypts it using Machine key. It then modifies the viewstate according to your serverside program and then finally encrypts it... converts the encrypted string to Base64 and written over Response stream. That means for every request this huge amount of task IIS has to perform. Hence slow output. We generally place EnableViewState = false for frequently visited pages to have better performance. So according to me writing a Dataset(which serializes it and write to page) is not good. On the other hand, Server memory is very low. If there are lots of connections, there might be a huge possibility to have Session OutofMemory. But if you dont have concurrent connections, you might use Session. But dont put the dataset, as there are a lots of properties which are not required. Rather make a list of DataRows and place them in session(Improves than writing DataSet). But still, I dont like this as well. If I was there, I will always compromise Database hits than Server memory. Abhishek Sur Don't forget to click "Good Answer" if you like this Solution. My Latest Articles--> Simplify Code Using NDepend Basics of Bing Search API using .NET Microsoft Bing MAP using Javascript Exception are Generated in Database Johndas3-Nov-09 0:54 Johndas 3-Nov-09 0:54  Hi All, In my project using Ajax controls that is update panel,Modal controls and VS 2008, i am getting the Error in Log Database.But application running very fine.Why this Exception is generated?The Application is in Live.... HandlingInstanceID: 0c17cc24-7940-4807-a07e-e92170031d69 An exception of type 'System.Web.HttpException' occurred and was caught. ------------------------------------------------------------------------ 11/01/2009 04:03:55 Type : System.Web.HttpException, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a Message : The file '/4L5rpd4F.asmx' does not exist. Source : System.Web Help link : ErrorCode : -2147467259 Data : System.Collections.ListDictionaryInternal TargetSite : Void CheckVirtualFileExists(System.Web.VirtualPath) Stack Trace : at System.Web.UI.Util.CheckVirtualFileExists(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath) at System.Web.UI.WebServiceParser.GetCompiledType(String inputFile, HttpContext context) at System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext context, String Please giving me any suggestion, by that i can resolve the problem.. Thanks in Advance. JohnDas

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